AGW Observer

Observations of anthropogenic global warming

Archive for August, 2018

Global warming hiatus paper list, version 1.0 (224 papers), part 2

Posted by Ari Jokimäki on August 6, 2018

Continued from part 1.

Papers 100 – 225

NR – 100
TY – JOUR
AU – Thorne, Peter
AU – Outten, Stephen
AU – Bethke, Ingo
AU – Seland, Øyvind
TI – Investigating the recent apparent hiatus in surface temperature increases: 2. Comparison of model ensembles to observational estimates
JO – Journal of Geophysical Research: Atmospheres
VL – 120
IS – 17
UR – http://dx.doi.org/10.1002/2014JD022805
DO – 10.1002/2014JD022805
SP – 8597
EP – 8620
PY – 2015
AB – To assess published hypotheses surrounding the recent slowdown in surface warming (hiatus), we compare five available global observational surface temperature estimates to two 30-member ensembles from the Norwegian Earth System Model (NorESM). Model ensembles are initialized in 1980 from the transient historical runs and driven with forcings used in the CMIP5 experiments and updated forcings based upon current observational understanding, described in Part 1. The ensembles’ surface temperature trends are statistically indistinguishable over 1998–2012 despite differences in the prescribed forcings. There is thus no evidence that forcing errors play a significant role in explaining the hiatus according to NorESM. The observations fall either toward the lower portion of the ensembles or, for some observational estimates and regions, outside. The exception is the Arctic where the observations fall toward the upper ensemble bounds. Observational data set choices can make a large difference to findings of consistency or otherwise. Those NorESM ensemble members that exhibit Nino3.4 Sea Surface Temperature (SST) trends similar to observed also exhibit comparable tropical and to some extent global mean trends, supporting a role for El Nino Southern Oscillation in explaining the hiatus. Several ensemble members capture the marked seasonality observed in Northern Hemisphere midlatitude trends, with cooling in the wintertime and warming in the remaining seasons. Overall, we find that we cannot falsify NorESM as being capable of explaining the observed hiatus behavior. Importantly, this is not equivalent to concluding NorESM could simultaneously capture all important facets of the hiatus. Similar experiments with further, distinct, Earth System Models are required to verify our findings.
ER –

NR – 101
TY – JOUR
AU – Fyfe, John C.
AU – Meehl, Gerald A.
AU – England, Matthew H.
AU – Mann, Michael E.
AU – Santer, Benjamin D.
AU – Flato, Gregory M.
AU – Hawkins, Ed
AU – Gillett, Nathan P.
AU – Xie, Shang-Ping
AU – Kosaka, Yu
AU – Swart, Neil C.
TI – Making sense of the early-2000s warming slowdown
JF – Nature Climate Change
PY – 2016
VL – 6
SP – 224
UR – http://dx.doi.org/10.1038/nclimate2938
DO – 10.1038/nclimate2938
AB – It has been claimed that the early-2000s global warming slowdown or hiatus, characterized by a reduced rate of global surface warming, has been overstated, lacks sound scientific basis, or is unsupported by observations. The evidence presented here contradicts these claims.
ER –

NR – 102
TY – JOUR
AU – Boykoff, Maxwell T.
TI – Media discourse on the climate slowdown
JF – Nature Climate Change
PY – 2014
VL – 4
SP – 156
UR – http://dx.doi.org/10.1038/nclimate2156
DO – 10.1038/nclimate2156
AB – We must not fall victim to decontextualized and ahistorical media accounting of climate trends.
ER –

NR – 103
TY – JOUR
AU – Somavilla, R.
AU – González-Pola, C.
AU – Schauer, U.
AU – Budéus, G.
TI – Mid-2000s North Atlantic shift: Heat budget and circulation changes
JO – Geophysical Research Letters
VL – 43
IS – 5
UR – http://dx.doi.org/10.1002/2015GL067254
DO – 10.1002/2015GL067254
SP – 2059
EP – 2068
PY – 2016
AB – Prior to the 2000s, the North Atlantic was the basin showing the greatest warming. However, since the mid-2000s during the so-called global warming hiatus, large amounts of heat were transferred in this basin from upper to deeper levels while the dominance in terms of atmospheric heat capture moved into the Indo-Pacific. Here we show that a large transformation of modal waters in the eastern North Atlantic (ENA) played a crucial role in such contrasting behavior. First, strong winter mixing in 2005 transformed ENA modal waters into a much saltier, warmer, and denser variety, transferring upper ocean heat and salt gained slowly over time to deeper layers. The new denser waters also altered the zonal dynamic height gradient reversing the southward regional flow and enhancing the access of saltier southern waters to higher latitudes. Then, the excess salinity in northern regions favored additional heat injection through deep convection events in later years.
ER –

NR – 104
TY – JOUR
T1 – Periodicities in mean sea-level fluctuations and climate change proxies: Lessons from the modelling for coastal management
AU – Baker, R.G.V.
AU – McGowan, S.A.
JO – Ocean & Coastal Management
VL – 98
SP – 187
EP – 201
PY – 2014
DO – https://doi.org/10.1016/j.ocecoaman.2014.05.027
UR – http://www.sciencedirect.com/science/article/pii/S0964569114001781
AB – The question of whether sea levels and global temperatures are accelerating or decelerating is a major source of current debate. Single taper and multi-taper spectral analysis from seventeen globally distributed tidal stations and twenty climate proxies show aggregate significant common periodicities in mean sea level fluctuations and the climate proxies of approximately 7 yr, 13 yr, 23 yr, 32 yr, 41 yr, 53 yr, 66 yr, 88 yr, 105 yr and 132 yr, respectively. These periods are shown to strongly correlate with an harmonic sequence of n, m = n + n/4 and p = n + n/2n for n = 5.5 yr and this synchronicity allows for a climate state function to be defined by Lotka–Volterra limit cycles. Such a model can include both anthropogenic warming and complex natural cycles, based on past evidence, and these cycles can form or bifurcate into extreme events close to critical values. The model suggests that accelerating sea levels can be in-phase, but lag decelerating global temperatures or vice versa, so a ‘pause’ in global warming should not be surprising. Further, the model can simulate the uneven regional effect of climate responses and replicate the chaos apparent in monthly sea-level records. The approach poses ‘a planner’s dilemma’ whereby the likelihood of a present 1 in 100 yr positive extreme event can either be caused by anthropogenic warming within shorter cycles or by a stationary mean in a longer cycle. We simply show that for rising average temperatures in a double period cascading model, there would be a three-fold increase in the likelihood of an equivalent 1 in 100 yr positive extreme event relative to present over a 20 yr period. A consequence to the ‘planner’s dilemma’ is the ‘manager’s risk imperative’ where risk cycles can be quantified into strategic GIS maps of potential future inundations: identifying vulnerability, defining possible economic impacts and underpinning response strategies that are legally defensible and transparent to a range of stakeholders.
ER –

NR – 105
TY – JOUR
AU – Morrison, Kyle W.
AU – Battley, Phil F.
AU – Sagar, Paul M.
AU – Thompson, David R.
PY – 2015
TI – Population dynamics of Eastern Rockhopper Penguins on Campbell Island in relation to sea surface temperature 1942–2012: current warming hiatus pauses a long-term decline
JO – Polar Biology
SP – 163
EP – 177
VL – 38
IS – 2
AB – Major population changes of marine mega-fauna are ongoing as global warming, and other anthropogenic drivers affect prey availability. The historical stronghold of the Eastern Rockhopper Penguin (Eudyptes chrysocome filholi) was New Zealand’s sub-Antarctic Campbell Island, but the population declined by 94 % between 1942 and 1984. The apparent mechanism of collapse was warm ocean temperatures causing an inadequate food supply. Eudyptes penguin population declines are ongoing at some breeding sites, highlighting the need to investigate the population trend on Campbell Island since 1984. We estimated the Eastern Rockhopper Penguin breeding population size through physical and photo-counts of birds and nests in 2012, and changes in colony area relative to 1984 and 1996 photographs. We estimated the 2012 population size at 33,239 breeding pairs, a 21.8 % decrease from an (adjusted) estimate of 42,528 pairs in 1984. Although substantial, the recent 1984–2012 decline occurred at a much slower rate (? = 0.991) than the 1942–1984 decline (? = 0.940). Despite great variation in trends between colonies ostensibly linked to differences in predation rates, the recent decline occurred primarily between 1984 and 1996, and thereafter the overall population grew. A 100-year time series of extended reconstructed sea surface temperatures (ERSST) confirmed that the population declined during warm periods and increased during cool periods, but that the initial decline began before increases in regional ERSST. Population growth after 1996 appears related to the current global warming hiatus, lower ERSST, and increased abundance of a key prey species. We predict a continuation of the long-term population decline after warming resumes.
UR – https://doi.org/10.1007/s00300-014-1575-x
DO – 10.1007/s00300-014-1575-x
ER –

NR – 106
TY – JOUR
AU – An, Wenling
AU – Hou, Shugui
AU – Zhang, Wangbin
AU – Wu, Shuangye
AU – Xu, Hao
AU – Pang, Hongxi
AU – Wang, Yetang
AU – Liu, Yaping
T1 – Possible recent warming hiatus on the northwestern Tibetan Plateau derived from ice core records
PY – 2016
AB – Many studies have reported enhanced warming trend on the Tibetan Plateau (TP), even during the warming hiatus period. However, most of these studies are based on instrumental data largely collected from the eastern TP, whereas the temperature trend over the extensive northwestern TP remains uncertain due to few meteorological stations. Here we combined the stable isotopic d(18)O record of an ice core recovered in 2012 from the Chongce glacier with the d(18)O records of two other ice cores (i.e., Muztagata and Zangser Kangri) in the same region to establish a regional temperature series for the northwestern TP. The reconstruction shows a significant warming trend with a rate of 0.74?±?0.12?°C/decade for the period 1970–2000, but a decreasing trend from 2001 to 2012. This is consistent with the reduction of warming rates during the recent decade observed at the only two meteorological stations on the northwestern TP, even though most stations on the eastern TP have shown persistent warming during the same period. Our results suggest a possible recent warming hiatus on the northwestern TP. This could have contributed to the relatively stable status of glaciers in this region.
SP – 32813
VL – 6
DO – 10.1038/srep32813
UR – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5017263/
JF – Scientific Reports
ER –

NR – 107
TY – JOUR
T1 – Present contributions to sea level rise by thermal expansion and ice melting and implication on coastal management
AU – Parker, Albert
JO – Ocean & Coastal Management
VL – 98
SP – 202
EP – 211
PY – 2014
DO – https://doi.org/10.1016/j.ocecoaman.2014.05.026
UR – http://www.sciencedirect.com/science/article/pii/S0964569114001744
AB – Increasing ocean heat content has been suggested on the basis of theories. Reconstructions (modelling results based on selected scattered measurements) and simulations (modelling results not based on observations) have both shown a significant warming since the year 1970 that increased at an ever faster rate over the 14 years this century. It is shown here that, contrary to this claim, the detailed measurements of the ocean temperature and salinity by the sampling buoys of the ARGO project show only minor changes of temperature and salinity since the early 2000s. The ARGO results cover the ocean layers 0–2000m except for the North and South Poles. The satellite NSSTC surface air temperature measurements over the world oceans show a global cooling over the last 11 years, and the satellite NSDIC sea ice extent measurements show globally increasing ice coverage over the North and South Poles. The North Pole sea ice is certainly reducing, but over the last 11 years the growth of the South Pole sea ice has more than compensated that loss. The true measurements are in marked contrast to theoretical reconstructions and simulations. This result has a huge implication on coastal management that should be based on observationally derived forecasts rather than “projections” of models lacking validation.
ER –

NR – 108
TY – JOUR
T1 – Recent hiatus caused by decadal shift in Indo-Pacific heating
JF – Science
SP – 532
LP – 535
DO – 10.1126/science.aaa4521
VL – 349
IS – 6247
AU – Nieves, Veronica
AU – Willis, Josh K.
AU – Patzert, William C.
UR – http://science.sciencemag.org/content/349/6247/532.abstract
AB – Global warming apparently slowed, or even stopped, during the first decade of the 21st century. This pause is commonly called the “hiatus.” We know, however, that Earth's climate system is accumulating excess solar energy owing to the build-up of greenhouse gases in the atmosphere. Where, then, has this energy gone if not into the air? Nieves et al. find that over this period, the surface Pacific Ocean has cooled but the upper Indian and Southern Oceans have warmed. Thus, the decade-long hiatus that began in 2003 would appear to be the result of a redistribution of heat within the ocean, rather than a change in the whole-Earth warming rate.Science, this issue p. 532Recent modeling studies have proposed different scenarios to explain the slowdown in surface temperature warming in the most recent decade. Some of these studies seem to support the idea of internal variability and/or rearrangement of heat between the surface and the ocean interior. Others suggest that radiative forcing might also play a role. Our examination of observational data over the past two decades shows some significant differences when compared to model results from reanalyses and provides the most definitive explanation of how the heat was redistributed. We find that cooling in the top 100-meter layer of the Pacific Ocean was mainly compensated for by warming in the 100- to 300-meter layer of the Indian and Pacific Oceans in the past decade since 2003.
ER –

NR – 109
TY – JOUR
AU – Gonzalez-Hidalgo, José Carlos
AU – Peña-Angulo, Dhais
AU – Brunetti, Michele
AU – Cortesi, Nicola
TI – Recent trend in temperature evolution in Spanish mainland (1951–2010): from warming to hiatus
JO – International Journal of Climatology
VL – 36
IS – 6
UR – http://dx.doi.org/10.1002/joc.4519
DO – 10.1002/joc.4519
SP – 2405
EP – 2416
PY – 2016
AB – The most recent debate on global warming focuses on the hiatus in global temperature, for which several explanations have been proposed. On the other hand, spatial variability and nonlinearity in temperature evolution has been recognized as a key point in global change analyses. In this study, we analyse the evolution of the warming rate in the Spanish mainland using the MOTEDAS data set for the last 60 years (1951–2010). Our special emphasis is on the last decades to detect and identify a possible hiatus, and to determine the effects of daytime (Tmax) and night-time (Tmin) records at annual and seasonal scale on the hiatus. Moving windows running trend analyses were applied to calculate temperature trend and significance for any temporal window from the beginning to the end of the series, ranging from 20 years to the whole series length (60 years) The results suggest that the warming rate in the Spanish mainland reached a maximum between 1970 and 1990, followed by a decrease in intensity in both Tmax and Tmin until the present. Furthermore, the decrease in the warming rate in Tmax has been higher than in Tmin for the last three decades; therefore, recent annual warming rates appears to depend more on Tmin than on Tmax. Significant trends disappear from the middle of the 1980s at any temporal window length in both Tmax and Tmin at annual and seasonal scales except in spring Tmin. Some differences among seasons are evident and, during the last few decades, the highest rates of warming are found in spring and summer, with Tmax and Tmin behaving in different ways. This study highlights how the warming rate is highly dependent on the length of the period analysed.
ER –

NR – 110
TY – JOUR
AU – Zhang, Yuanjie
AU – Gao, Zhiqiu
AU – Pan, Zaitao
AU – Li, Dan
AU – Wan, Bingcheng
TI – Record-breaking temperatures in China during the warming and recent hiatus periods
JO – Journal of Geophysical Research: Atmospheres
VL – 121
IS – 1
UR – http://dx.doi.org/10.1002/2015JD023886
DO – 10.1002/2015JD023886
SP – 241
EP – 258
PY – 2016
AB – The observed and modeled record-breaking temperature (RBT) frequency in China is analyzed for different segments of the period 1961–2050 including the hiatus period. It is found that significant changes in the RBT frequency occurred earlier, with greater amplitude, for daily minimum temperatures (TN) compared to maximum temperatures (TX) during the past five decades. Changes in the RBT frequency can be mostly explained by the mean warming trend, especially for TN, while in summer also slightly by variance. Moreover, mean climate change affects more the multiday mean RBT than the single-day counterpart as RBT occurrence is inversely proportional to variance that is smaller for multiday means. In the hiatus period (1998–2013), the ratios of record highs to lows in summer continue to increase in southern China primarily due to the lower frequency of record lows, since the decreasing temperature variance suppressed the increase in record highs under the summer warming. While the winter ratios decreased significantly across most of the country due to the winter cooling. Model simulations show a much smaller asymmetry of the RBT frequency between TX and TN as compared to the observations. The 28-model median overestimates the ratios for TX owning to missing the relative cooling in the “warming hole” region and is unable to reproduce the RBT characteristics in the hiatus period. Under a high-emission scenario, increasing rates of future temperature extremes are projected to accelerate with almost doubling ratio trends in the first half of 21st century compared to the historical results.
ER –

NR – 111
TY – JOUR
T1 – Revisiting the Relationship between Observed Warming and Surface Pressure in the Tibetan Plateau
AU – You, Qinglong
AU – Jiang, Zhihong
AU – Moore, G. W. K.
AU – Bao, Yuntao
AU – Kong, Lei
AU – Kang, Shichang
PY – 2016
DO – 10.1175/JCLI-D-15-0834.1
JF – Journal of Climate
SP – 1721
EP – 1737
VL – 30
IS – 5
AB – The Tibetan Plateau (TP) has an average elevation of over 4000 m and with its surrounding mountains is regarded as Earth?s ?third pole.? As a result of its size and height, climate change in the TP has its own unique characteristics that include a proposed positive correlation between the surface temperature and pressure. This study examines the trends and relationships between the surface pressure and temperature in the TP through the examination of monthly mean data from 71 stations during 1961?2013. On annual, seasonal, and monthly time scales, the TP exhibits a statistically significant warming trend that attains a rate of 0.30°C decade?1 for annual means over the period 1961?2013. The most pronounced warming occurs in winter, in agreement with previous studies, with evidence of acceleration in the rate after the mid-1980s and the global warming slowdown period. For the entire period of 1961?2013, the surface pressure in the TP has a positive trend of 0.08 hPa decade?1 on an annual basis, again with the largest trends occurring in winter. However, unlike what occurred with the surface temperature, the trend in surface pressure, in most cases, reversed sign after the mid-1980s. The trend in the geopotential height at 500 hPa from the National Centers for Environmental Prediction?National Center for Atmospheric Research (NCEP?NCAR) reanalysis is consistent with the observed surface pressure trends. Over the period 1961?2013, there is a seasonal shift in the nature of the relationship between the surface temperature and pressure with a negative correlation during summer and autumn, and a positive correlation during winter. This suggests that the nature of the relationship between these two climate elements reflects the changing nature of the seasonal snow cover (land surface property) and cloud in the region.
UR – https://doi.org/10.1175/JCLI-D-15-0834.1
ER –

NR – 112
TY – JOUR
T1 – Revisiting Whether Recent Surface Temperature Trends Agree with the CMIP5 Ensemble
AU – Lin, Marena
AU – Huybers, Peter
PY – 2016
DO – 10.1175/JCLI-D-16-0123.1
JF – Journal of Climate
SP – 8673
EP – 8687
VL – 29
IS – 24
AB – In an earlier study, a weaker trend in global mean temperature over the past 15 years relative to the preceding decades was characterized as significantly lower than those contained within the phase 5 of the Coupled Model Intercomparison Project (CMIP5) ensemble. In this study, divergence between model simulations and observations is estimated using a fixed-intercept linear trend with a slope estimator that has one-third the noise variance compared to simple linear regression. Following the approach of the earlier study, where intermodel spread is used to assess the distribution of trends, but using the fixed-intercept trend metric demonstrates that recently observed trends in global mean temperature are consistent with the CMIP5 ensemble for all 15-yr intervals of observation?model divergence since 1970. Significant clustering of global trends according to modeling center indicates that the spread in CMIP5 trends is better characterized using ensemble members drawn across models as opposed to using ensemble members from a single model. Despite model?observation consistency at the global level, substantial regional discrepancies in surface temperature trends remain.
UR – https://doi.org/10.1175/JCLI-D-16-0123.1
ER –

NR – 113
TY – JOUR
T1 – Role of Changes in Mean Temperatures versus Temperature Gradients in the Recent Widening of the Hadley Circulation
AU – Adam, Ori
AU – Schneider, Tapio
AU – Harnik, Nili
PY – 2014
DO – 10.1175/JCLI-D-14-00140.1
JF – Journal of Climate
SP – 7450
EP – 7461
VL – 27
IS – 19
AB – The Hadley circulation (HC) has widened in recent decades, and it widens as the climate warms in simulations. But the mechanisms responsible for the widening remain unclear, and the widening in simulations is generally smaller than observed.To identify mechanisms responsible for the HC widening and for model?observation discrepancies, this study analyzes how interannual variations of tropical-mean temperatures and meridional temperature gradients influence the HC width. Changes in mean temperatures are part of any global warming signal, whereas changes in temperature gradients are primarily associated with ENSO. Within this study, 6 reanalysis datasets, 22 Atmospheric Modeling Intercomparison Project (AMIP) simulations, and 11 historical simulations from phase 5 of the Climate Modeling Intercomparison Project (CMIP5) are analyzed, covering the years 1979?2012. It is found that the HC widens as mean temperatures increase or as temperature gradients weaken in most reanalyses and climate models. On average, climate models exhibit a smaller sensitivity of HC width to changes in mean temperatures and temperature gradients than do reanalyses. However, the sensitivities differ substantially among reanalyses, rendering the HC response to mean temperatures in climate models not statistically different from that in reanalyses.While global-mean temperatures did not increase substantially between 1997 and 2012, the HC continued to widen in most reanalyses. The analysis here suggests that the HC widening from 1979 to 1997 is primarily the result of global warming, whereas the widening of the HC from 1997 to 2012 is associated with increased midlatitude temperatures and hence reduced temperature gradients during this period.
UR – https://doi.org/10.1175/JCLI-D-14-00140.1
ER –

NR – 114
TY – JOUR
AU – Wei, Meng
AU – Qiao, FangLi
PY – 2017
TI – Attribution analysis for the failure of CMIP5 climate models to simulate the recent global warming hiatus
JO – Science China Earth Sciences
SP – 397
EP – 408
VL – 60
IS – 2
AB – The Coupled Model Inter-comparison Project Phase 5 (CMIP5) contains a group of state-of-the-art climate models and represents the highest level of climate simulation thus far. However, these models significantly overestimated global mean surface temperature (GMST) during 2006–2014. Based on the ensemble empirical mode decomposition (EEMD) method, the long term change of the observed GMST time series of HadCRUT4 records during 1850–2014 was analyzed, then the simulated GMST by 33 CMIP5 climate models was assessed. The possible reason that climate models failed to project the recent global warming hiatus was revealed. Results show that during 1850–2014 the GMST on a centennial timescale rose with fluctuation, dominated by the secular trend and the multi-decadal variability (MDV). The secular trend was relatively steady beginning in the early 20th century, with an average warming rate of 0.0883°C/decade over the last 50 years. While the MDV (with a ~65-year cycle) showed 2.5 multi-decadal waves during 1850–2014, which deepened and steepened with time, the alarming warming over the last quarter of the 20th century was a result of the concurrence of the secular warming trend and the warming phase of the MDV, both of which accounted one third of the temperature increase during 1975–1998. Recently the slowdown of global warming emerged as the MDV approached its third peak, leading to a reduction in the warming rate. A comparative analysis between the GMST time series derived from HadCRUT4 records and 33 CMIP5 model outputs reveals that the GMSTs during the historical simulation period of 1850–2005 can be reproduced well by models, especially on the accelerated global warming over the last quarter of 20th century. However, the projected GMSTs and their linear trends during 2006–2014 under the RCP4.5 scenario were significantly higher than observed. This is because the CMIP5 models confused the MDV with secular trend underlying the GMST time series, which results in a fast secular trend and an improper MDV with irregular phases and small amplitudes. This implies that the role of atmospheric CO2 in global warming may be overestimated, while the MDV which is an interior oscillation of the climate system may be underestimated, which should be related to insufficient understanding of key climatic internal dynamic processes. Our study puts forward an important criterion for the new generation of climate models: they should be able to simulate both the secular trend and the MDV of GMST.
UR – https://doi.org/10.1007/s11430-015-5465-y
DO – 10.1007/s11430-015-5465-y
ER –

NR – 115
TY – JOUR
AU – Zhou, Chunlüe
AU – Wang, Kaicun
T1 – Coldest Temperature Extreme Monotonically Increased and Hottest Extreme Oscillated over Northern Hemisphere Land during Last 114 Years
PY – 2016
AB – Most studies on global warming rely on global mean surface temperature, whose change is jointly determined by anthropogenic greenhouse gases (GHGs) and natural variability. This introduces a heated debate on whether there is a recent warming hiatus and what caused the hiatus. Here, we presented a novel method and applied it to a 5°?×?5° grid of Northern Hemisphere land for the period 1900 to 2013. Our results show that the coldest 5% of minimum temperature anomalies (the coldest deviation) have increased monotonically by 0.22?°C/decade, which reflects well the elevated anthropogenic GHG effect. The warmest 5% of maximum temperature anomalies (the warmest deviation), however, display a significant oscillation following the Atlantic Multidecadal Oscillation (AMO), with a warming rate of 0.07?°C/decade from 1900 to 2013. The warmest (0.34?°C/decade) and coldest deviations (0.25? °C/decade) increased at much higher rates over the most recent decade than last century mean values, indicating the hiatus should not be interpreted as a general slowing of climate change. The significant oscillation of the warmest deviation provides an extension of previous study reporting no pause in the hottest temperature extremes since 1979, and first uncovers its increase from 1900 to 1939 and decrease from 1940 to 1969.
SP – 25721
VL – 6
DO – 10.1038/srep25721
UR – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4865736/
JF – Scientific Reports
ER –

NR – 116
TY – JOUR
AU – Dai, Aiguo
AU – Fyfe, John C.
AU – Xie, Shang-Ping
AU – Dai, Xingang
TI – Decadal modulation of global surface temperature by internal climate variability
JF – Nature Climate Change
PY – 2015
VL – 5
SP – 555
UR – http://dx.doi.org/10.1038/nclimate2605
DO – 10.1038/nclimate2605
AB – Despite a steady increase in atmospheric greenhouse gases (GHGs), global-mean surface temperature (T) has shown no discernible warming since about 2000, in sharp contrast to model simulations, which on average project strong warming1,2,3. The recent slowdown in observed surface warming has been attributed to decadal cooling in the tropical Pacific1,4,5, intensifying trade winds5, changes in El Niño activity6,7, increasing volcanic activity8,9,10 and decreasing solar irradiance7. Earlier periods of arrested warming have been observed but received much less attention than the recent period, and their causes are poorly understood. Here we analyse observed and model-simulated global T fields to quantify the contributions of internal climate variability (ICV) to decadal changes in global-mean T since 1920. We show that the Interdecadal Pacific Oscillation (IPO) has been associated with large T anomalies over both ocean and land. Combined with another leading mode of ICV, the IPO explains most of the difference between observed and model-simulated rates of decadal change in global-mean T since 1920, and particularly over the so-called ‘hiatus’ period since about 2000. We conclude that ICV, mainly through the IPO, was largely responsible for the recent slowdown, as well as for earlier slowdowns and accelerations in global-mean T since 1920, with preferred spatial patterns different from those associated with GHG-induced warming or aerosol-induced cooling. Recent history suggests that the IPO could reverse course and lead to accelerated global warming in the coming decades.
ER –

NR – 117
TY – JOUR
AU – Lin, Yong
AU – Franzke, Christian L. E.
TI – Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming
JF – Scientific Reports
PY – 2015
VL – 5
SP – 12971
UR – http://dx.doi.org/10.1038/srep12971
DO – 10.1038/srep12971
AB – Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary.
ER –

NR – 118
TY – JOUR
T1 – Does the NMME Capture a Recent Decadal Shift toward Increasing Drought Occurrence in the Southwestern United States?
AU – Barnston, Anthony G.
AU – Lyon, Bradfield
PY – 2015
DO – 10.1175/JCLI-D-15-0311.1
JF – Journal of Climate
SP – 561
EP – 581
VL – 29
IS – 2
AB – A global-scale decadal climate shift, beginning in 1998/99 and enduring through 2013, has been documented in recent studies, with associated precipitation shifts in key regions throughout the world. These precipitation shifts are most easily detected during March?May when ENSO effects are weak. Analyses have linked this climate shift to a shift in the Pacific decadal variability (PDV) pattern to its negative phase. Here the authors evaluate the predictive skill of the North American Multimodel Ensemble (NMME), and the CFSv2 model alone, in maintaining the observed precipitation shifts in seasonal forecasts, emphasizing the southwestern United States where deficient precipitation has tended to prevail since the late 1990s.The NMME hindcasts out to 6 months lead are found to maintain the observed decadal precipitation shifts in key locations qualitatively correctly, but with increasingly underestimated amplitude with increasing lead time. This finding holds in the separate CFSv2 model hindcasts. The decadal precipitation shift is relatively well reproduced in the southwestern United States. The general underestimation of the precipitation shift is suggested to be related to a muted reproduction of the observed shift in Pacific sea surface temperature (SST). This conclusion is supported by runs from a different (but overlapping) set of atmospheric models, which when forced with observed SST reproduce the decadal shifts quite well. Overall, the capability of the NMME model hindcasts to reflect the observed decadal rainfall pattern shift, but with weakened amplitude (especially at longer leads), underscores the broader challenge of retaining decadal signals in predictions of droughts and pluvials at seasonal-to-interannual time scales.
UR – https://doi.org/10.1175/JCLI-D-15-0311.1
ER –

NR – 119
TY – JOUR
AU – Knutson, Thomas R.
AU – Ploshay, Jeffrey J.
PY – 2016
TI – Detection of anthropogenic influence on a summertime heat stress index
JO – Climatic Change
SP – 25
EP – 39
VL – 138
IS – 1
AB – One of the most consequential impacts of anthropogenic warming on humans may be increased heat stress, combining temperature and humidity effects. Here we examine whether there are now detectable changes in summertime heat stress over land regions. As a heat stress metric we use a simplified wet bulb globe temperature (WBGT) index. Observed trends in WBGT (1973–2012) are compared to trends from CMIP5 historical simulations (eight-model ensemble) using either anthropogenic and natural forcing agents combined or natural forcings alone. Our analysis suggests that there has been a detectable anthropogenic increase in mean summertime heat stress since 1973, both globally and in most land regions analyzed. A detectable increase is found over a larger fraction of land for WBGT than for temperature, as WBGT summertime means have lower interannual variability than surface temperature at gridbox scales. Notably, summertime WBGT over land has continued increasing in recent years–consistent with climate models–despite the apparent ‘hiatus’ in global warming and despite a decreasing tendency in observed relative humidity over land since the late 1990s.
UR – https://doi.org/10.1007/s10584-016-1708-z
DO – 10.1007/s10584-016-1708-z
ER –

NR – 120
TY – JOUR
AU – Dong, Lu
AU – Zhou, Tianjun
AU – Dai, Aiguo
AU – Song, Fengfei
AU – Wu, Bo
AU – Chen, Xiaolong
TI – The Footprint of the Inter-decadal Pacific Oscillation in Indian Ocean Sea Surface Temperatures
JO – Scientific Reports
PY – 2016
VL – 6
SP – 21251
UR – http://dx.doi.org/10.1038/srep21251
DO – 10.1038/srep21251
AB – Superimposed on a pronounced warming trend, the Indian Ocean (IO) sea surface temperatures (SSTs) also show considerable decadal variations that can cause regional climate oscillations around the IO. However, the mechanisms of the IO decadal variability remain unclear. Here we perform numerical experiments using a state-of-the-art, fully coupled climate model in which the external forcings with or without the observed SSTs in the tropical eastern Pacific Ocean (TEP) are applied for 1871–2012. Both the observed timing and magnitude of the IO decadal variations are well reproduced in those experiments with the TEP SSTs prescribed to observations. Although the external forcings account for most of the warming trend, the decadal variability in IO SSTs is dominated by internal variability that is induced by the TEP SSTs, especially the Inter-decadal Pacific Oscillation (IPO). The IPO weakens (enhances) the warming of the external forcings by about 50% over the IO during IPO’s cold (warm) phase, which contributes about 10% to the recent global warming hiatus since 1999. The decadal variability in IO SSTs is modulated by the IPO-induced atmospheric adjustment through changing surface heat fluxes, sea surface height and thermocline depth.
ER –

NR – 121
TY – JOUR
AU – Blanchette, Jeanne
AU – Huang, Yi
TI – Earth Infrared Radiation Spectra During Global Warming Hiatus
JO – McGill Science Undergraduate Research Journal
PY – 2015
VL – 10
IS – 1
SP – 14
EP – 17
UR – http://msurj.mcgill.ca/vol10/iss1/MSURJ2015.pdf#page=14
AB – Background: Since 1997-98, observations of annual mean surface temperature have shown a slowdown of global temperature increases, suggesting a hiatus in global warming. Given this finding, we are interested in diagnosing trends in the Earth’s outgoing longwave radiation (OLR) spectrum throughout the last decade. Methods: We calculated the trend in OLR measured by the Atmospheric Infrared Sounder (AIRS) aboard NASA’s Aqua satellite between 2003 and 2013, and compared these results with the trend in atmospheric and surface temperature and tropospheric absolute humidity, obtained from AIRS retrieval product and from the ECMWF (European Center for Medium range Weather Forecasting) Re-Analysis (ERA) interim product. We also isolated the greenhouse effect from the OLR trend by subtracting the amount of surface radiation emitted from the total radiation received by the sounder. Results: The OLR trend is negative in the CO2 absorption band, negative in the window spectral region, and positive in the water vapor band. The trend in surface and tropospheric temperature is negative, as is the trend in tropospheric absolute humidity. The greenhouse effect is increasing in the CO2 band, generally slightly increasing in the window region, and decreasing in the H2O band. Conclusion: Our results show that the CO2 forcing was still present globally through the last decade, with steadily increasing effects. Contributors to the negative trend in OLR in the window region are a small decrease in surface temperature and a strong decrease in tropospheric temperature, where tropospheric H2O emit radiation to space. The decreasing effect of water vapor in the H2O band is due to decreasing tropospheric humidity. This analysis will allow us to detect the changes in greenhouse gas forcing, to examine the correlated surface temperature response, and to study changes and effects in tropospheric water vapor concentration.
ER –

NR – 122
TY – JOUR
AU – Zhou, Chunlüe
AU – Wang, Kaicun
TI – Spatiotemporal Divergence of the Warming Hiatus over Land Based on Different Definitions of Mean Temperature
JO – Scientific Reports
PY – 2016
VL – 6
SP – 31789
UR – http://dx.doi.org/10.1038/srep31789
DO – 10.1038/srep31789
AB – Existing studies of the recent warming hiatus over land are primarily based on the average of daily minimum and maximum temperatures (T2). This study compared regional warming rates of mean temperature based on T2 and T24 calculated from hourly observations available from 1998 to 2013. Both T2 and T24 show that the warming hiatus over land is apparent in the mid-latitudes of North America and Eurasia, especially in cold seasons, which is closely associated with the negative North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) and cold air propagation by the Arctic-original northerly wind anomaly into mid-latitudes. However, the warming rates of T2 and T24 are significantly different at regional and seasonal scales because T2 only samples air temperature twice daily and cannot accurately reflect land-atmosphere and incoming radiation variations in the temperature diurnal cycle. The trend has a standard deviation of 0.43?°C/decade for T2 and 0.41?°C/decade for T24, and 0.38?°C/decade for their trend difference in 5°?×?5° grids. The use of T2 amplifies the regional contrasts of the warming rate, i.e., the trend underestimation in the US and overestimation at high latitudes by T2.
ER –

NR – 123
TY – JOUR
AU – Urabe, Yusuke
AU – Maeda, Shuhei
TI – The Relationship between Japans Recent Temperature and Decadal Variability
JO – SOLA
PY – 2014
DA – 2014
VL – 10
SP – 176-179
UR – https://ci.nii.ac.jp/naid/130004704543/en/
DO – 10.2151/sola.2014-037
AB – Since the late 1990s, surface temperature has been higher than (near or lower than) normal for summer/autumn (winter/spring) over Japan, indicating that the seasonal temperature contrast has become enhanced. In order to relate this to global-scale variability on decadal timescale, atmospheric re-analysis and ocean assimilation datasets were analyzed. It is suggested that the La Niña-like conditions which have been frequently observed in the tropical Pacific oceanic and atmospheric fields in the last decade have contributed to these temperature tendencies observed in Japan. These global characteristics are consistent with the global warming hiatus. The results presented here indicate that not only interannual variability and century-scale long-term trends but also decadal variability in global oceanic and atmospheric fields significantly affect Japans temperature.
ER –

NR – 124
TY – JOUR
AU – He, Haozhe
AU – Yang, Jing
AU – Wu, Liguang
AU – Gong, Daoyi
AU – Wang, Bin
AU – Gao, Miaoni
PY – 2017
TI – Unusual growth in intense typhoon occurrences over the Philippine Sea in September after the mid-2000s
JO – Climate Dynamics
SP – 1893
EP – 1910
VL – 48
IS – 5
AB – During the global warming hiatus period (1998–present), a pronounced increase in the number of intense typhoon occurrences was identified over the Philippine Sea (PS: 5°–25°N, 125°–140°E) in September after the mid-2000s. Comparing two periods before and after the mid-2000s indicates that intense typhoons rarely occurred over the PS in September before the mid-2000s, with a frequency of fewer than 0.4 per year, but reached up to nearly 1.5 per year after the mid-2000s. The abrupt increase in intense typhoon occurrences over the PS was primarily attributed to increased tropical cyclone (TC) genesis and favorable large-scale conditions for TC intensification. The increase in TC genesis number over the PS was caused by contributory dynamical conditions, including positive low-level relative vorticity anomalies and anomalous ascents, which corresponded to a southwestward shift and strengthening of the monsoon trough. In addition, among the favorable large-scale conditions, the increased relative humidity that resulted from intensified moisture flux convergence exerted essential effect on the TC intensification. These changes in atmospheric environmental conditions favoring intense typhoon occurrences over the PS were primarily associated with the change in the tropical Indo-Pacific sea surface temperature (SST) around the mid-2000s. Besides that, the positive feedback TCs exerted on the circulation was also conducive to the unusual growth in intense typhoon occurrences over the PS. And note that the role of SST anomalies in the air–sea interaction is the key to interpret why the unique phenomenon only occurred in September.
UR – https://doi.org/10.1007/s00382-016-3181-9
DO – 10.1007/s00382-016-3181-9
ER –

NR – 125
TY – JOUR
AU – Lovejoy, S.
TI – Using scaling for macroweather forecasting including the pause
JO – Geophysical Research Letters
VL – 42
IS – 17
UR – http://dx.doi.org/10.1002/2015GL065665
DO – 10.1002/2015GL065665
SP – 7148
EP – 7155
PY – 2015
AB – The ScaLIng Macroweather model (SLIMM) is a new class of stochastic atmospheric model. It exploits the large system memory to overcome the biases of conventional numerical climate models, it makes hindcasts and forecasts over macroweather forecast horizons (˜10?days to decades). Using the simplest (scalar), SLIMM model with only two parameters, we present various twentieth century hindcasts including several of the slowdown (“pause”) in the warming since 1998. The 1999–2013 hindcast is accurate to within ±0.11?K, with all the 2002–2013 anomalies hindcast to within ±0.02?K. In comparison, the Climate Model Intercomparison Project Phase 3 hindcasts were on average about 0.2?K too warm.
ER –

NR – 126
TY – JOUR
AU – Guan, Xiaodan
AU – Huang, Jianping
AU – Guo, Ruixia
AU – Lin, Pu
TI – The role of dynamically induced variability in the recent warming trend slowdown over the Northern Hemisphere
JO – Scientific Reports
PY – 2015
VL – 5
SP – 12669
UR – http://dx.doi.org/10.1038/srep12669
DO – 10.1038/srep12669
AB – Since the slowing of the trend of increasing surface air temperature (SAT) in the late 1990?s, intense interest and debate have arisen concerning the contribution of human activities to the warming observed in previous decades. Although several explanations have been proposed for the warming-trend slowdown (WTS), none has been generally accepted. We investigate the WTS using a recently developed methodology that can successfully identify and separate the dynamically induced and radiatively forced SAT changes from raw SAT data. The dynamically induced SAT changes exhibited an obvious cooling effect relative to the warming effect of the adjusted SAT in the hiatus process. A correlation analysis suggests that the changes are dominated primarily by the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO). Our results confirm that dynamically induced variability caused the WTS. The radiatively forced SAT changes are determined mainly by anthropogenic forcing, indicating the warming influence of greenhouse gases (GHGs), which reached levels of 400?ppm during the hiatus period. Therefore, the global SAT will not remain permanently neutral. The increased radiatively forced SAT will be amplified by increased dynamically induced SAT when the natural mode returns to a warming phase in the next period.
ER –

NR – 127
TY – JOUR
AU – Pasini, Antonello
AU – Triacca, Umberto
AU – Attanasio, Alessandro
PY – 2017
TI – Evidence for the role of the Atlantic multidecadal oscillation and the ocean heat uptake in hiatus prediction
JO – Theoretical and Applied Climatology
SP – 873
EP – 880
VL – 129
IS – 3
AB – The recent hiatus in global temperature at the surface has been analysed by several studies, mainly using global climate models. The common accepted picture is that since the late 1990s, the increase in anthropogenic radiative forcings has been counterbalanced by other factors, e.g., a decrease in natural forcings, augmented ocean heat storage and negative phases of ocean–atmosphere-coupled oscillation patterns. Here, simple vector autoregressive models are used for forecasting the temperature hiatus in the period 2001–2014. This gives new insight into the problem of understanding the ocean contribution (in terms of heat uptake and atmosphere–ocean-coupled oscillations) to the appearance of this recent hiatus. In particular, considering data about the ocean heat content until a depth of 700 m and the Atlantic multidecadal oscillation is necessary for correctly forecasting the hiatus, so catching both trend and interannual variability. Our models also show that the ocean heat uptake is substantially driven by the natural component of the total radiative forcing at a decadal time scale, confining the importance of the anthropogenic influences to a longer range warming of the ocean.
UR – https://doi.org/10.1007/s00704-016-1818-6
DO – 10.1007/s00704-016-1818-6
ER –

NR – 128
TY – JOUR
T1 – Extreme North America Winter Storm Season of 2013/14: Roles of Radiative Forcing and the Global Warming Hiatus
AU – Yang, Xiaosong
AU – Vecchi, G. A.
AU – Delworth, T. L.
AU – Paffendorf, K.
AU – Jia, L.
AU – Gudgel, R.
AU – Zeng, F.
AU – Underwood, Seth D.
PY – 2015
DO – 10.1175/BAMS-D-15-00133.1
JF – Bulletin of the American Meteorological Society
SP – S25
EP – S28
VL – 96
IS – 12
UR – https://doi.org/10.1175/BAMS-D-15-00133.1
AB – The extreme 2013/14 winter storm season over much of North America was made more likely by the multiyear anomalous tropical Pacific winds associated with the recent global warming hiatus.
ER –

NR – 129
TY – JOUR
AU – Huang, Rui Xin
PY – 2015
TI – Heaving modes in the world oceans
JO – Climate Dynamics
SP – 3563
EP – 3591
VL – 45
IS – 11
AB – Part of climate changes on decadal time scales can be interpreted as the result of adiabatic motions associated with the adjustment of wind-driven circulation, i.e., the heaving of the isopycnal surfaces. Heat content changes in the ocean, including hiatus of global surface temperature and other phenomena, can be interpreted in terms of heaving associated with adjustment of wind-driven circulation induced by decadal variability of wind. A simple reduced gravity model is used to examine the consequence of adiabatic adjustment of the wind-driven circulation. Decadal changes in wind stress forcing can induce three-dimensional redistribution of warm water in the upper ocean. In particular, wind stress change can generate baroclinic modes of heat content anomaly in the vertical direction; in fact, changes in stratification observed in the ocean may be induced by wind stress change at local or in the remote parts of the world oceans. Intensification of the equatorial easterly can induce cooling in the upper layer and warming in the subsurface layer. The combination of this kind of heat content anomaly with the general trend of warming of the whole water column under the increasing greenhouse effect may offer an explanation for the hiatus of global surface temperature and the accelerating subsurface warming over the past 10–15 years. Furthermore, the meridional transport of warm water in the upper ocean can lead to sizeable transient meridional overturning circulation, poleward heat flux and vertical heat flux. Thus, heaving plays a key role in the oceanic circulation and climate.
UR – https://doi.org/10.1007/s00382-015-2557-6
DO – 10.1007/s00382-015-2557-6
ER –

NR – 130
TY – JOUR
AU – Zhou, Chen
AU – Zelinka, Mark D.
AU – Klein, Stephen A.
TI – Impact of decadal cloud variations on the Earth’s energy budget
JO – Nature Geoscience
PY – 2016
VL – 9
SP – 871
UR – http://dx.doi.org/10.1038/ngeo2828
DO – 10.1038/ngeo2828
AB – Feedbacks of clouds on climate change strongly influence the magnitude of global warming1,2,3. Cloud feedbacks, in turn, depend on the spatial patterns of surface warming4,5,6,7,8,9, which vary on decadal timescales. Therefore, the magnitude of the decadal cloud feedback could deviate from the long-term cloud feedback4. Here we present climate model simulations to show that the global mean cloud feedback in response to decadal temperature fluctuations varies dramatically due to time variations in the spatial pattern of sea surface temperature. We find that cloud anomalies associated with these patterns significantly modify the Earth’s energy budget. Specifically, the decadal cloud feedback between the 1980s and 2000s is substantially more negative than the long-term cloud feedback. This is a result of cooling in tropical regions where air descends, relative to warming in tropical ascent regions, which strengthens low-level atmospheric stability. Under these conditions, low-level cloud cover and its reflection of solar radiation increase, despite an increase in global mean surface temperature. These results suggest that sea surface temperature pattern-induced low cloud anomalies could have contributed to the period of reduced warming between 1998 and 2013, and offer a physical explanation of why climate sensitivities estimated from recently observed trends are probably biased low4.
ER –

NR – 131
TY – JOUR
AU – Wang, Linying
AU – Yuan, Xing
AU – Xie, Zhenghui
AU – Wu, Peili
AU – Li, Yaohui
TI – Increasing flash droughts over China during the recent global warming hiatus
JO – Scientific Reports
PY – 2016
VL – 6
SP – 30571
UR – http://dx.doi.org/10.1038/srep30571
DO – 10.1038/srep30571
AB – The recent global warming slowdown or hiatus after the big El Niño event in 1997/98 raises the questions of whether terrestrial hydrological cycle is being decelerated and how do the hydrological extremes respond to the hiatus. However, the rapidly developing drought events that are termed as “flash droughts” accompanied by extreme heat, low soil moisture and high evapotranspiration (ET), occurred frequently around the world, and caused devastating impacts on crop yields and water supply. Here, we investigate the long-term trend and variability of flash droughts over China. Flash droughts are most likely to occur over humid and semi-humid regions, such as southern and northeastern China. Flash drought averaged over China increased by 109% from 1979 to 2010, and the increase was mainly due to a long term warming of temperature (50%), followed by the contributions from decreasing soil moisture and increasing ET. There was a slight drop in temperature after 1997, but the increasing trend of flash droughts was tripled. Further results indicate that the decreasing temperature was compensated by the accelerated drying trends of soil moisture and enhanced ET, leading to an acceleration of flash droughts during the warming hiatus. The anthropogenic warming in the next few decades may exacerbate future flash drought conditions in China.
ER –

NR – 132
TY – JOUR
TI – Investigation on the Tendencies of the Land–Ocean Warming Contrast in the Recent Decades
SP – 1522
EP – 1526
AU – L. Zhao
AU – J. Xu
AU – A. Powell
AU – D. Guo
AU – C. Shi
AU – M. Shao
AU – D. Wang
PY – 2016
DO – 10.1109/LGRS.2016.2594954
JO – IEEE Geoscience and Remote Sensing Letters
IS – 10
VL – 13
AB – In this letter, the surface climate temperature trends for the land and the oceans (land-ocean warming contrast) have been examined and compared based on five data sets. The five data sets included three reconstructed data sets of surface temperature observations and two data sets derived using the satellite microwave sounding unit retrieval products in the lower troposphere (LT) for the period from January 1980 to December 2014. Unlike previous studies, the current study shows that the warming trends significantly decreased over both the land and ocean since 1992 and reached their minimum (near zero) in the early 2000s, which is consistent with the occurrence of the warming hiatus. However, due to the sharp decrease in the surface warming trend over the land (1992 to 2007) in conjunction with an increase in the ocean surface warming trend after 2002, the combined trend carries an overall positive sign (between 2005 and 2007) due to the greater ocean warming trend. The rate of warming increase in the ocean, which began in 2002, is surprisingly fast and is approaching the highest warming trends observed over the land since 1980. These basic land and ocean trend results are confirmed by all five data sets with slightly different values due to the various techniques used in compiling the data sets. However, there is consistency in the overall trend pattern results.
ER –

NR – 133
TY – JOUR
AU – Santer, Benjamin D.
AU – Solomon, Susan
AU – Bonfils, Céline
AU – Zelinka, Mark D.
AU – Painter, Jeffrey F.
AU – Beltran, Francisco
AU – Fyfe, John C.
AU – Johannesson, Gardar
AU – Mears, Carl
AU – Ridley, David A.
AU – Vernier, Jean-Paul
AU – Wentz, Frank J.
TI – Observed multivariable signals of late 20th and early 21st century volcanic activity
JO – Geophysical Research Letters
VL – 42
IS – 2
UR – http://dx.doi.org/10.1002/2014GL062366
DO – 10.1002/2014GL062366
SP – 500
EP – 509
PY – 2015
AB – The relatively muted warming of the surface and lower troposphere since 1998 has attracted considerable attention. One contributory factor to this “warming hiatus” is an increase in volcanically induced cooling over the early 21st century. Here we identify the signals of late 20th and early 21st century volcanic activity in multiple observed climate variables. Volcanic signals are statistically discernible in spatial averages of tropical and near-global SST, tropospheric temperature, net clear-sky short-wave radiation, and atmospheric water vapor. Signals of late 20th and early 21st century volcanic eruptions are also detectable in near-global averages of rainfall. In tropical average rainfall, however, only a Pinatubo-caused drying signal is identifiable. Successful volcanic signal detection is critically dependent on removal of variability induced by the El Niño–Southern Oscillation.
ER –

NR – 134
TY – JOUR
AU – Peyser, Cheryl E.
AU – Yin, Jianjun
AU – Landerer, Felix W.
AU – Cole, Julia E.
TI – Pacific sea level rise patterns and global surface temperature variability
JO – Geophysical Research Letters
VL – 43
IS – 16
UR – http://dx.doi.org/10.1002/2016GL069401
DO – 10.1002/2016GL069401
SP – 8662
EP – 8669
PY – 2016
AB – During 1998–2012, climate change and sea level rise (SLR) exhibit two notable features: a slowdown of global surface warming (hiatus) and a rapid SLR in the tropical western Pacific. To quantify their relationship, we analyze the long-term control simulations of 38 climate models. We find a significant and robust correlation between the east-west contrast of dynamic sea level (DSL) in the Pacific and global mean surface temperature (GST) variability on both interannual and decadal time scales. Based on linear regression of the multimodel ensemble mean, the anomalously fast SLR in the western tropical Pacific observed during 1998–2012 indicates suppression of a potential global surface warming of 0.16°?±?0.06°C. In contrast, the Pacific contributed 0.29°?±?0.10°C to the significant interannual GST increase in 1997/1998. The Pacific DSL anomalies observed in 2015 suggest that the strong El Niño in 2015/2016 could lead to a 0.21°?±?0.07°C GST jump.
ER –

NR – 135
TY – JOUR
AU – Chikamoto, Y.
AU – Mochizuki, T.
AU – Timmermann, A.
AU – Kimoto, M.
AU – Watanabe, M.
TI – Potential tropical Atlantic impacts on Pacific decadal climate trends
JO – Geophysical Research Letters
VL – 43
IS – 13
UR – http://dx.doi.org/10.1002/2016GL069544
DO – 10.1002/2016GL069544
SP – 7143
EP – 7151
PY – 2016
AB – The tropical Pacific cooling from the early 1990s to 2013 has contributed to the slowdown of globally averaged sea surface temperatures (SSTs). The origin of this regional cooling trend still remains elusive. Here we demonstrate that the remote impact of Atlantic SST anomalies, as well as local atmosphere-ocean interactions, contributed to the eastern Pacific cooling during this period. By assimilating observed three-dimensional Atlantic temperature and salinity anomalies into a coupled general circulation model, we are able to qualitatively reproduce the observed Pacific decadal trends of SST and sea level pressure (SLP), albeit with reduced amplitude. Although a major part of the Pacific SLP trend can be explained by equatorial Pacific SST forcing only, the origin of this low-frequency variability can be traced back further to the remote impacts of equatorial Atlantic and South Atlantic SST trends. Atlantic SST impacts on the atmospheric circulation can also be detected for the Northeastern Pacific, thus providing a linkage between Atlantic climate and Western North American drought conditions.
ER –

NR – 136
TY – JOUR
AU – Ramesh, Nandini
AU – Cane, Mark A.
AU – Seager, Richard
AU – Lee, Dong Eun
PY – 2017
TI – Predictability and prediction of persistent cool states of the Tropical Pacific Ocean
JO – Climate Dynamics
SP – 2291
EP – 2307
VL – 49
IS – 7
AB – The Tropical Pacific Ocean displays persistently cool sea surface temperature (SST) anomalies that last several years to a decade, with either no El Niño events or a few weak El Niño events. These cause large-scale droughts in the extratropics, including major North American droughts such as the 1930s Dust Bowl, and also modulate the global mean surface temperature. Here we show that two models with different levels of complexity—the Zebiak–Cane intermediate model and the Geophysical Fluid Dynamics Laboratory Coupled Model version 2.1—are able to produce such periods in a realistic manner. We then test the predictability of these periods in the Zebiak–Cane model using an ensemble of experiments with perturbed initial states. Our results show that in most cases the cool mean state is predictable. We then apply this method to make retrospective forecasts of shifts in the decadal mean state and to forecast the mean state of the Tropical Pacific Ocean for the upcoming decade. Our results suggest that the Pacific will undergo a shift to a warmer mean state after the 2015–2016 El Niño. This could imply the cessation of the drier than normal conditions that have generally afflicted southwest North America since the 1997–1998 El Niño, as well as the twenty-first-century pause in global warming. Implications for our understanding of the origins of such persistent cool states and the possibility of improving predictions of large-scale droughts are discussed.
UR – https://doi.org/10.1007/s00382-016-3446-3
DO – 10.1007/s00382-016-3446-3
ER –

NR – 137
TY – JOUR
AU – Knutson, Thomas R.
AU – Zhang, Rong
AU – Horowitz, Larry W.
TI – Prospects for a prolonged slowdown in global warming in the early 21st century
JO – Nature Communications
PY – 2016
VL – 7
SP – 13676
UR – http://dx.doi.org/10.1038/ncomms13676
DO – 10.1038/ncomms13676
AB – Global mean temperature over 1998 to 2015 increased at a slower rate (0.1?K decade-1) compared with the ensemble mean (forced) warming rate projected by Coupled Model Intercomparison Project 5 (CMIP5) models (0.2?K decade-1). Here we investigate the prospects for this slower rate to persist for a decade or more. The slower rate could persist if the transient climate response is overestimated by CMIP5 models by a factor of two, as suggested by recent low-end estimates. Alternatively, using CMIP5 models’ warming rate, the slower rate could still persist due to strong multidecadal internal variability cooling. Combining the CMIP5 ensemble warming rate with internal variability episodes from a single climate model—having the strongest multidecadal variability among CMIP5 models—we estimate that the warming slowdown (<0.1?K decade-1 trend beginning in 1998) could persist, due to internal variability cooling, through 2020, 2025 or 2030 with probabilities 16%, 11% and 6%, respectively.
ER –

NR – 138
TY – JOUR
AU – Gleisner, Hans
AU – Thejll, Peter
AU – Christiansen, Bo
AU – Nielsen, Johannes K.
TI – Recent global warming hiatus dominated by low-latitude temperature trends in surface and troposphere data
JO – Geophysical Research Letters
VL – 42
IS – 2
UR – http://dx.doi.org/10.1002/2014GL062596
DO – 10.1002/2014GL062596
SP – 510
EP – 517
PY – 2015
AB – Over the last 15 years, global mean surface temperatures exhibit only weak trends. Recent studies have attempted to attribute this so called temperature hiatus to several causes, amongst them incomplete sampling of the rapidly warming Arctic region. We here examine zonal mean temperature trends in satellite-based tropospheric data sets (based on data from (Advanced) Microwave Sounding Unit and Global Navigation Satellite System Radio Occultation instruments) and in global surface temperatures (HadCRUT4). Omission of successively larger polar regions from the global mean temperature calculations, in both tropospheric and surface data sets, shows that data gaps at high latitudes cannot explain the observed differences between the hiatus and the prehiatus period. Instead, the dominating causes of the global temperature hiatus are found at low latitudes. The combined use of several independent data sets, representing completely different measurement techniques and sampling characteristics, strengthens the conclusions.
ER –

NR – 139
TY – JOUR
AU – England, Matthew H.
AU – Kajtar, Jules B.
AU – Maher, Nicola
TI – Robust warming projections despite the recent hiatus
JO – Nature Climate Change
PY – 2015
VL – 5
SP – 394
UR – http://dx.doi.org/10.1038/nclimate2575
DO – 10.1038/nclimate2575
AB – The hiatus in warming has led to questions about the reliability of long-term projections, yet here we show they are statistically unchanged when considering only ensemble members that capture the recent hiatus. This demonstrates the robust nature of twenty-first century warming projections.
ER –

NR – 140
TY – JOUR
T1 – Role of Indian Ocean SST variability on the recent global warming hiatus
AU – Arora, Anika
AU – Rao, Suryachandra A.
AU – Chattopadhyay, R.
AU – Goswami, Tanmoy
AU – George, Gibies
AU – Sabeerali, C.T.
JO – Global and Planetary Change
VL – 143
SP – 21
EP – 30
PY – 2016
DO – https://doi.org/10.1016/j.gloplacha.2016.05.009
UR – http://www.sciencedirect.com/science/article/pii/S0921818115300412
AB – Previous studies have shown a slowdown in the warming rate of the annual mean global surface temperature in the recent decade and it is referred to as the hiatus in global warming. Some recent studies have suggested that the hiatus in global warming is possibly due to strong cooling in the tropical Pacific. This study investigates the possible role of the Indian Ocean warming on the tropical Pacific cooling. Despite the continued rise in sea surface temperature (SST) over the tropical Indian Ocean, SST over the tropical Pacific has shown a cooling trend in the recent decade (2002 – 2012). It is well known fact that the Indian Ocean and the Pacific Ocean are strongly coupled to each other and the Indian Ocean basin wide warming is triggered by El Niño on interannual time scale. However, in the recent decade, this relationship is weakening. The recent Indian Ocean warming is triggering a Matsuno-Gill type response in the atmosphere by generating anomalous cyclonic circulations on either side of equator over the tropical Indian Ocean and anomalous easterlies along the tropical Pacific Ocean. These anomalous easterlies result in Ekman divergence in the equatorial Pacific and produce upwelling Kelvin waves, cools the tropical Pacific and therefore indirectly contributes to the hiatus in global warming.
ER –

NR – 141
TY – JOUR
T1 – A Significant Component of Unforced Multidecadal Variability in the Recent Acceleration of Global Warming
AU – DelSole, Timothy
AU – Tippett, Michael K.
AU – Shukla, Jagadish
PY – 2010
DO – 10.1175/2010JCLI3659.1
JF – Journal of Climate
SP – 909
EP – 926
VL – 24
IS – 3
AB – The problem of separating variations due to natural and anthropogenic forcing from those due to unforced internal dynamics during the twentieth century is addressed using state-of-the-art climate simulations and observations. An unforced internal component that varies on multidecadal time scales is identified by a new statistical method that maximizes integral time scale. This component, called the internal multidecadal pattern (IMP), is stochastic and hence does not contribute to trends on long time scales; however, it can contribute significantly to short-term trends. Observational estimates indicate that the trend in the spatially averaged ?well observed? sea surface temperature (SST) due to the forced component has an approximately constant value of 0.1 K decade?1, while the IMP can contribute about ±0.08 K decade?1 for a 30-yr trend. The warming and cooling of the IMP matches that of the Atlantic multidecadal oscillation and is of sufficient amplitude to explain the acceleration in warming during 1977?2008 as compared to 1946?77, despite the forced component increasing at the same rate during these two periods. The amplitude and time scale of the IMP are such that its contribution to the trend dominates that of the forced component on time scales shorter than 16 yr, implying that the lack of warming trend during the past 10 yr is not statistically significant. Furthermore, since the IMP varies naturally on multidecadal time scales, it is potentially predictable on decadal time scales, providing a scientific rationale for decadal predictions. While the IMP can contribute significantly to trends for periods of 30 yr or shorter, it cannot account for the 0.8°C warming that has been observed in the twentieth-century spatially averaged SST.
UR – https://doi.org/10.1175/2010JCLI3659.1
ER –

NR – 142
TY – JOUR
T1 – Changes in Aridity in Response to Warming Hiatus
AU – Guan, Xiaodan
AU – Huang, Jianping
AU – Guo, Ruixia
PY – 2016
JF – Journal of Meteorological Research
VL – 31
SP – 117
EP – 125
DO – 10.1007/s13351-017-6038-1
AB – The global warming trend slowdown or warming hiatus began around the year 2000 and has persisted for nearly 15 years. Most studies have focused on the interpretation underlying this temperature change. In this study, changes in the global aridity index (AI) were analyzed using a newly developed dynamical adjustment method that can successfully identify and separate dynamically induced and radiatively-forced aridity changes in the raw data. The AI and Palmer Drought Severity Index (PDSI) appeared a wetting zone over the mid-to-high latitudes of the Northern Hemisphere in recent decades. The dynamical adjustment analysis suggests that this wetting zone occurred in response to the global warming hiatus. The dynamically-induced AI (DAI) played a major role in the AI changes during the hiatus period, and its relationships with the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO) and Atlantic Multi-decadal Oscillation (AMO) also indicate that different phases of the NAO, PDO, and AMO contributed to different performance of the DAI over the Northern Hemisphere. Although the aridity wetting over the mid-to-high latitudes may relieve long-term drying in certain regions, the hiatus is temporary, and so is the relief. Accelerated global warming will return when the NAO, PDO, and AMO revert to their opposite phases in the future, and the wetting zone is likely to disappear.
ER –

NR – 143
TY – JOUR
AU – Tan, Ming
PY – 2016
TI – Circulation background of climate patterns in the past millennium: Uncertainty analysis and re-reconstruction of ENSO-like state
JO – Science China Earth Sciences
SP – 1225
EP – 1241
VL – 59
IS – 6
AB – The question of whether or not global warming has paused since more than ten years ago, namely “warming hiatus”, has attracted the attention of climate science community including the IPCC. Some authors have attributed the “warming hiatus” to the internal changes in the climate system, i.e., the recombination of ocean-atmosphere circulations. Therefore, it is necessary to propose higher requirements on reconstructing circulation background of climate change for the past millennium. However, the analyses of changes in atmospheric circulation over the last millennium as well as the conclusions of related regional climate patterns are so widely different and contradictory, bringing uncertainties to our understanding of regional even global climate change to a great extent. On the other hand, in the last 10 years the high-precision U/Th-dated stalagmite oxygen isotope ratio (d18O) sequences provided an accurate chronological frame for the paleoclimate study of the middle and late Pleistocene, in which all authors from China took the Chinese stalagmite d18O as the summer monsoon index without exception. However, this point of view misleads the climate scientists into thinking that the stalagmite d18O can be as the proxy of precipitation amount. Nevertheless, it is well known that all of these records have a lot in common in the low frequency trend. However, most sequences cannot be calibrated by instrumental precipitation records, and thus the uncertainty of the climate research framework of China and even of the world has increased. Therefore, it is imperative for climatology to clarify the origin of contradiction and to reduce the uncertainty as early as possible. On the basis of analyzing the significance of stalagmite d18O in the monsoon regions of China, the author tries to propose a new circulation proxy in this paper: integrating the Chinese stalagmite oxygen isotope sequence to reconstruct the tropical Pacific sea surface temperature gradient, i.e., the large-scale ENSO-like state over the past millennium. Furthermore, the author speculates that it was warm in the modern times and the Medieval Period, but the circulation recombination was different in both periods. And this inference could be supported by the longer record since Last Glacial Maximum. In other words, the attribution analysis of the identical low-frequency trends of Chinese stalagmite d18O on a large scale shows that the ENSO-like state controls the climate change in the monsoon regions of China at different time scales (from interannual to century or even longer time scales). Wherein the important connection of circulations is the western Pacific subtropical high (WPSH), that is to say, besides the interannual and decadal time scales, the WPSH would possess the circulation mode on longer timescales. For example, we may discuss the change of the WPSH in the whole Holocene epoch, i.e., the half precession period. These discussions could make sense to the study of not only the paleoclimate but also the modern climate.
UR – https://doi.org/10.1007/s11430-015-5256-6
DO – 10.1007/s11430-015-5256-6
ER –

NR – 144
TY – JOUR
AU – Cheng, Lijing
AU – Zheng, Fei
AU – Zhu, Jiang
T1 – Distinctive ocean interior changes during the recent warming slowdown
PY – 2015
AB – The earth system experiences continuous heat input, but a “climate hiatus” of upper ocean waters has been observed in this century. This leads to a question: where is the extra heat going? Using four in situ observation datasets, we explore the ocean subsurface temperature changes from 2004 to 2013. The observations all show that the ocean has continued to gain heat in this century, which is indicative of anthropogenic global warming. However, a distinctive pattern of change in the interior ocean is observed. The sea surface (1–100?m) temperature has decreased in this century, accompanied by warming in the 101–300?m layer. This pattern is due to the changes in the frequency of El Niño and La Niña events (ENSO characteristics), according to both observations and CMIP5 model simulations. In addition, we show for the first time that the ocean subsurface within 301–700?m experienced a net cooling, indicative of another instance of variability in the natural ocean. Furthermore, the ocean layer of 701–1500?m has experienced significant warming.
SP – 14346
VL – 5
DO – 10.1038/srep14346
UR – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4585812/
JF – Scientific Reports
ER –

NR – 145
TY – JOUR
AU – Jochner, Susanne
AU – Menzel, Annette
TI – Does flower phenology mirror the slowdown of global warming?
JO – Ecology and Evolution
VL – 5
IS – 11
UR – http://dx.doi.org/10.1002/ece3.1503
DO – 10.1002/ece3.1503
SP – 2284
EP – 2295
PY – 2015
AB – Although recent global warming trends in air temperature are not as pronounced as those observed only one decade ago, global mean temperature is still at a very high level. Does plant phenology – which is believed to be a suitable indicator of climate change – respond in a similar way, that is, does it still mirror recent temperature variations? We explored in detail long-term flowering onset dates of snowdrop, cherry, and lime tree and relevant spring temperatures at three sites in Germany (1901–2012) using the Bayesian multiple change-point approach. We investigated whether mean spring temperature changes were amplified or slowed down in the past decade and how plant phenology responded to the most recent temperature changes. Incorporating records with different end points (i.e., 2002 and 2012), we compared differences in trends and inferred possible differences caused by extrapolating phenological and meteorological data. The new multiple-change point approach is characterized by an enhanced structure and greater flexibility compared to the one change point model. However, the highest model probabilities for phenological (meteorological) records were still obtained for the one change point (linear) model. Marked warming trends in the recent decade were only revealed for mean temperatures of March to May, here better described with one or two change point models. In the majority of cases analyzed, changes in temperatures were well mirrored by phenological changes. However, temperatures in March to May were linked to less strongly advancing onset dates for lime tree flowering during the period 1901-2012, pointing to the likely influence of photoperiodic constraints or unfulfilled chilling requirements. Due to the slowdown of temperature increase, analyses conducted on records ending in 2002 demonstrated distinct differences when compared with records ending in 2012. Extrapolation of trends could therefore (along with the choice of the statistical method) lead to distinctly different results and most recent data should be integrated in order not to over- or underestimate future phenological changes.
ER –

NR – 146
TY – JOUR
AU – Dieng, Habib B.
AU – Palanisamy, Hindumathi
AU – Cazenave, Anny
AU – Meyssignac, Benoit
AU – von Schuckmann, Karina
PY – 2015
TI – The Sea Level Budget Since 2003: Inference on the Deep Ocean Heat Content
JO – Surveys in Geophysics
SP – 209
EP – 229
VL – 36
IS – 2
AB – This study provides an overview of the various components of the global mean sea level evolution over two time spans: (1) 2005–2012 (corresponding to the full deployment of the Argo program) and (2) 2003–2012. Using a sea level budget approach, we compare altimetry-based global mean sea level, global ocean mass from GRACE space gravimetry and steric sea level from Argo and other in situ measurements. One goal of this study is to investigate whether it is possible to constrain the deep ocean contribution to the global mean sea level rise over the last decade. This question is particularly relevant, considering the current debate about the ‘hiatus,’ i.e., the observed recent pause of the global mean air and sea surface temperature evolution while the planet is still in thermal imbalance. We consider a total of 16 different data sets. Differences are noticed between data sets related to each variable (sea level, ocean mass and steric sea level), mostly due to data processing issues. Therefore, we perform the analysis using averages of the available data sets. For each period, we find that, when removing from the global mean sea level, the contributions of the global mean ocean mass and steric sea level (estimated for the 0–1,500 m ocean layer), there remains a residual signal displaying a positive slope of 0.3 ± 0.6 and 0.55 ± 0.6 mm/year over 2005–2012 and 2003–2012, respectively. Comparing with an ocean reanalysis and according to direct (but sparse) ocean temperature measurements below 1,500 m, it seems unlikely that the observed residual signal can be attributed to deep (below 1,500 m) ocean warming, in agreement with other recently published results. We estimate that it possibly reflects, at least partly, the signature of a missing upper ocean steric signal in regions uncovered by current observing systems. Our study also shows a steady warming increase since 2003 of the 700–1,500 m ocean layer (amounting ~0.2 mm/year in steric sea level equivalent), confirming previous findings, but seen in our study in each of the eight different steric data sets considered.
UR – https://doi.org/10.1007/s10712-015-9314-6
DO – 10.1007/s10712-015-9314-6
ER –

NR – 147
TY – JOUR
AU – Ying, Lingxiao
AU – Shen, Zehao
AU – Piao, Shilong
TI – The recent hiatus in global warming of the land surface: Scale-dependent breakpoint occurrences in space and time
JO – Geophysical Research Letters
VL – 42
IS – 15
UR – http://dx.doi.org/10.1002/2015GL064884
DO – 10.1002/2015GL064884
SP – 6471
EP – 6478
PY – 2015
AB – The spatial and temporal variability of the recent land warming hiatus have seldom been explored, despite their importance for understanding the mechanisms underlying the phenomenon. In this study, we applied piecewise linear regression to investigate the spatiotemporal patterns of the breakpoint time of warming over 40?years (1974–2013). Our results showed that at the global scale, mean annual temperature (MAT) over the land increased significantly until 2005 and that the warming trend then stalled. However, the breakpoint time of the warming varied greatly among different seasons and continents. We found no statistically significant breakpoint in MAT over the Northern Hemisphere, but MAT over the Southern Hemisphere showed a significant breakpoint (P? 0.5), with root mean squared error 1500m. The Hilbert spectrum from the OHC in the Labrador Sea interior reveals two important components at frequencies of 0.8-1.2cycleyr-1 (T=0.8–1.25 years) and 0.1-0.3cycleyr-1 (T=3.3–10 years), respectively, superimposed on the warming trends. The former corresponds to the dominant seasonal cycle due to surface heating, while the latter is concomitant with the timing of the reoccurrence of convective events. We also found that the cumulative North Atlantic Oscillation (NAO) index significantly correlates to the low-frequency OHC variations. Therefore, the interannual signals in the Labrador Sea at especially the intermediate layers are attributed to changes in the deep convective processes and the atmospheric conditions. By comparing with an extended OHC record (1945–2010), it was further shown that the warming trends obtained from the 10-year Argo record are part of multi-decadal variations that presumably reflect the Atlantic Multi-decadal Oscillation (AMO). In addition, the recent OHC changes in the Labrador Sea (i.e., increased heat in the deeper layers) may be related to the current global warming hiatus, suggesting the potential contributions from the Atlantic Meridional Overturning Circulation (AMOC) to the low-frequency OHC in the Labrador Sea.
ER –

NR – 148
TY – JOUR
AU – Regayre, L. A.
AU – Pringle, K. J.
AU – Booth, B. B. B.
AU – Lee, L. A.
AU – Mann, G. W.
AU – Browse, J.
AU – Woodhouse, M. T.
AU – Rap, A.
AU – Reddington, C. L.
AU – Carslaw, K. S.
TI – Uncertainty in the magnitude of aerosol-cloud radiative forcing over recent decades
JO – Geophysical Research Letters
VL – 41
IS – 24
UR – http://dx.doi.org/10.1002/2014GL062029
DO – 10.1002/2014GL062029
SP – 9040
EP – 9049
PY – 2014
AB – Aerosols and their effect on the radiative properties of clouds are one of the largest sources of uncertainty in calculations of the Earth’s energy budget. Here the sensitivity of aerosol-cloud albedo effect forcing to 31 aerosol parameters is quantified. Sensitivities are compared over three periods; 1850–2008, 1978–2008, and 1998–2008. Despite declining global anthropogenic SO2 emissions during 1978–2008, a cancelation of regional positive and negative forcings leads to a near-zero global mean cloud albedo effect forcing. In contrast to existing negative estimates, our results suggest that the aerosol-cloud albedo effect was likely positive (0.006 to 0.028Wm-2) in the recent decade, making it harder to explain the temperature hiatus as a forced response. Proportional contributions to forcing variance from aerosol processes and natural and anthropogenic emissions are found to be period dependent. To better constrain forcing estimates, the processes that dominate uncertainty on the timescale of interest must be better understood.
ER –

NR – 149
TY – JOUR
AU – Sévellec, F.
AU – Sinha, B.
AU – Skliris, N.
TI – The rogue nature of hiatuses in a global warming climate
JO – Geophysical Research Letters
VL – 43
IS – 15
UR – http://dx.doi.org/10.1002/2016GL068950
DO – 10.1002/2016GL068950
SP – 8169
EP – 8177
PY – 2016
AB – The nature of rogue events is their unlikelihood and the recent unpredicted decade-long slowdown in surface warming, the so-called hiatus, may be such an event. However, given decadal variability in climate, global surface temperatures were never expected to increase monotonically with increasing radiative forcing. Here surface air temperature from 20 climate models is analyzed to estimate the historical and future likelihood of hiatuses and “surges” (faster than expected warming), showing that the global hiatus of the early 21st century was extremely unlikely. A novel analysis of future climate scenarios suggests that hiatuses will almost vanish and surges will strongly intensify by 2100 under a “business as usual” scenario. For “CO2 stabilisation” scenarios, hiatus, and surge characteristics revert to typical 1940s values. These results suggest to study the hiatus of the early 21st century and future reoccurrences as rogue events, at the limit of the variability of current climate modelling capability.
ER –

NR – 150
TY – JOUR
T1 – Variations of the Global Net Air–Sea Heat Flux during the “Hiatus” Period (2001–10)
AU – Liang, Xinfeng
AU – Yu, Lisan
PY – 2016
DO – 10.1175/JCLI-D-15-0626.1
JF – Journal of Climate
SP – 3647
EP – 3660
VL – 29
IS – 10
AB – An assessment is made of the mean and variability of the net air?sea heat flux, Qnet, from four products (ECCO, OAFlux?CERES, ERA-Interim, and NCEP1) over the global ice-free ocean from January 2001 to December 2010. For the 10-yr ?hiatus? period, all products agree on an overall net heat gain over the global ice-free ocean, but the magnitude varies from 1.7 to 9.5 W m?2. The differences among products are particularly large in the Southern Ocean, where they cannot even agree on whether the region gains or loses heat on the annual mean basis. Decadal trends of Qnet differ significantly between products. ECCO and OAFlux?CERES show almost no trend, whereas ERA-Interim suggests a downward trend and NCEP1 shows an upward trend. Therefore, numerical simulations utilizing different surface flux forcing products will likely produce diverged trends of the ocean heat content during this period. The downward trend in ERA-Interim started from 2006, driven by a peculiar pattern change in the tropical regions. ECCO, which used ERA-Interim as initial surface forcings and is constrained by ocean dynamics and ocean observations, corrected the pattern. Among the four products, ECCO and OAFlux?CERES show great similarities in the examined spatial and temporal patterns. Given that the two estimates were obtained using different approaches and based on largely independent observations, these similarities are encouraging and instructive. It is more likely that the global net air?sea heat flux does not change much during the so-called hiatus period.
UR – https://doi.org/10.1175/JCLI-D-15-0626.1
ER –

NR – 151
TY – JOUR
AU – Wang, You-Lin
AU – Wu, Chau-Ron
AU – Chao, Shenn-Yu
TI – Warming and weakening trends of the Kuroshio during 1993–2013
JO – Geophysical Research Letters
VL – 43
IS – 17
UR – http://dx.doi.org/10.1002/2016GL069432
DO – 10.1002/2016GL069432
SP – 9200
EP – 9207
PY – 2016
AB – Global warming seems leveling off somewhat during 1993–2013 despite increasing atmospheric greenhouse gases. What has happened to the Kuroshio Current system concurrently? Available independent data sets from 1993 to 2013 point to a single answer. Here we show a systemwide weakened Kuroshio during the period despite enhanced warming along its path. The Pacific warm pool upstream of the Kuroshio is still becoming warmer during the period. It injects more heat into the Current despite the weakened Kuroshio, which is associated with weakened westerlies and cyclonic trends of basin-scale wind stress curl. The weakened Kuroshio will modulate heat and mass exchanges between the tropics and extratropics, impacting the energy balance of climate system. It will also significantly influence mass, heat, salinity, and nutrient exchanges between the Pacific and adjacent marginal seas, which in turn impacts the regional weather, fisheries, and environments.
ER –

NR – 152
TY – JOUR
AU – Pretis, Felix
AU – Mann, Michael L.
AU – Kaufmann, Robert K.
PY – 2015
TI – Testing competing models of the temperature hiatus: assessing the effects of conditioning variables and temporal uncertainties through sample-wide break detection
JO – Climatic Change
SP – 705
EP – 718
VL – 131
IS – 4
AB – Explaining the recent slowdown in the rise of global mean surface temperature (the hiatus in warming) has become a major focus of climate research. Efforts to identify the causes of the hiatus that compare simulations from experiments run by climate models raise several statistical issues. Specifically, it is necessary to identify whether an experiment’s inability to simulate the hiatus is unique to this period or reflects a more systematic failure throughout the sample period. Furthermore, efforts to attribute the hiatus to a particular factor by including that mechanism in an experimental treatment must improve the model’s performance in a statistically significant manner at the time of the hiatus. Sample-wide assessments of simulation errors can provide an accurate assessment of whether or not the control experiment uniquely fails at the hiatus, and can identify its causes using experimental treatments. We use this approach to determine if the hiatus constitutes a unique failure in simulated climate models and to re- examine the conclusion that the hiatus is uniquely linked to episodes of La Niña-like cooling (Kosaka and Xie 2013). Using statistical techniques that do not define the hiatus a priori, we find no evidence that the slowdown in temperature increases are uniquely tied to episodes of La Niña-like cooling.
UR – https://doi.org/10.1007/s10584-015-1391-5
DO – 10.1007/s10584-015-1391-5
ER –

NR – 153
TY – JOUR
TI – Weakening of the Kuroshio Intrusion Into the South China Sea Under the Global Warming Hiatus
SP – 5064
EP – 5070
AU – C. R. Wu
AU – Y. L. Wang
AU – Y. F. Lin
AU – T. L. Chiang
AU – C. C. Wu
PY – 2016
DO – 10.1109/JSTARS.2016.2574941
JO – IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
IS – 11
VL – 9
AB – We analyze a 22-year (1993-2014) record of the Kuroshio intrusion (KI) index defined from maps of mean absolute dynamic topography west of Luzon Island in the Philippines to investigate the long-term trend of the KI into the South China Sea (SCS). The monotonically increasing trend of the KI index extracted by empirical mode decomposition implies a slight decreasing trend of the meridional pressure gradient across the Luzon Strait, suggesting a weakening of the KI into the SCS based on the geostrophy. This weakening is largely due to an intensification of the upstream Kuroshio east of Luzon, which is closely correlated with the latitude of the North Equatorial Current (NEC) bifurcation off the Philippines. We also find that the latitude of the NEC bifurcation has tended to migrate southward in recent years, coincident with the strengthening of the Kuroshio east of Luzon. The forcing of the trends of low-latitude circulation is attributable to changing surface wind fields in the tropical Pacific. The trade winds have intensified in response to the recent global warming hiatus, and an anomalous cyclonic wind field has appeared over the Philippine Sea. Both of these phenomena have contributed to the southward migration of the NEC bifurcation latitude in recent years. This has led to enhance the Kuroshio transport east of Luzon, and the Kuroshio has tended to bypass the Luzon Strait without significant westward encroachment.
ER –

NR – 154
TY – JOUR
AU – Vuille, Mathias
AU – Franquist, Eric
AU – Garreaud, René
AU – Lavado Casimiro, Waldo Sven
AU – Cáceres, Bolivar
TI – Impact of the global warming hiatus on Andean temperature
JO – Journal of Geophysical Research: Atmospheres
VL – 120
IS – 9
UR – http://dx.doi.org/10.1002/2015JD023126
DO – 10.1002/2015JD023126
SP – 3745
EP – 3757
PY – 2015
AB – The recent hiatus in global warming is likely to be reflected in Andean temperature, given its close dependence on tropical Pacific sea surface temperature (SST). While recent work in the subtropical Andes has indeed documented a cooling along coastal areas, trends in the tropical Andes show continued warming. Here we analyze spatiotemporal temperature variability along the western side of the Andes with a dense station network updated to 2010 and investigate its linkages to tropical Pacific modes of variability. Results indicate that the warming in tropical latitudes has come to a halt and that the subtropical regions continue to experience cooling. Trends, however, are highly dependent on elevation. While coastal regions experience cooling, higher elevations continue to warm. The coastal cooling is consistent with the observed Pacific Decadal Oscillation (PDO) fingerprint and can be accurately simulated using a simple PDO-analog model. Much of the PDO imprint is modulated and transmitted through adjustments in coastal SST off western South America. At inland and higher-elevation locations, however, temperature trends start to diverge from this PDO-analog model in the late 1980s and have by now emerged above the 1s model spread. Future warming at higher elevation is likely and will contribute to further vertical stratification of atmospheric temperature trends. In coastal locations, future warming or cooling will depend on the potential future intensification of the South Pacific anticyclone but also on continued temperature dependence on the state of the PDO.
ER –

NR – 155
TY – JOUR
AU – Gu, Guojun
AU – Adler, Robert F.
AU – Huffman, George J.
PY – 2016
TI – Long-term changes/trends in surface temperature and precipitation during the satellite era (1979–2012)
JO – Climate Dynamics
SP – 1091
EP – 1105
VL – 46
IS – 3
AB – During the post-1979 period in which the satellite-based precipitation measurements with global coverage are available, global mean surface temperature rapidly increased up to late 1990s, followed by a period of temperature hiatus after about 1998/1999. Comparing observed surface temperature trends against the simulated ones by the CMIP5 historical experiments especially in the zonal mean context suggests that although the anthropogenic greenhouse-gases (GHG) forcing has played a major role, in addition to the anthropogenic aerosols and various natural forcings, the effects from decadal-to-interdecadal-scale internal modes specifically the Pacific Decadal Oscillation (PDO) are also very strong. Evident temperature changes associated with the PDO’s phase shift are seen in the Pacific basin, with decadal-scale cooling in the tropical central-eastern Pacific and most of the east basin and concurrent warming in the subtropics of both hemispheres, even though the PDO’s net effect on global mean temperature is relatively weak. The Atlantic Multidecadal Oscillation (AMO) also changed its phase in the mid-1990s, and hence its possible impact is estimated and assessed as well. However, comparisons with CMIP5 simulations suggest that the AMO may have not contributed as significantly as the PDO in terms of the changes/trends in global surface temperature, even though the data analysis technique used here suggests otherwise. Long-term precipitation changes or trends during the post-1979 period are further shown to have been modulated by the two major factors: anthropogenic GHG and PDO, in addition to the relatively weak effects from aerosols and natural forcings. The spatial patterns of observed precipitation trends in the Pacific, including reductions in the tropical central-eastern Pacific and increases in the tropical western Pacific and along the South Pacific Convergence Zone, manifest the PDO’s contributions. Removing the PDO effect from the total precipitation trends makes the spatial structures of precipitation trends more similar to those simulated by CMIP5 historical full forcing experiments particularly in the context of zonal-mean results. This also confirms that in spite of the PDO effect specifically on regional scales, the anthropogenic GHG signals are still discernible in observed precipitation during the time period. Following the increase of GHG, precipitation tends to increase roughly along the climatological ITCZ and decrease south of the equator and in the subtropics of both hemispheres.
UR – https://doi.org/10.1007/s00382-015-2634-x
DO – 10.1007/s00382-015-2634-x
ER –

NR – 156
TY – JOUR
AU – Lee, Sang-Ki
AU – Park, Wonsun
AU – Baringer, Molly O.
AU – Gordon, Arnold L.
AU – Huber, Bruce
AU – Liu, Yanyun
TI – Pacific origin of the abrupt increase in Indian Ocean heat content during the warming hiatus
JA – Nature Geoscience
PY – 2015
VL – 8
SP – 445
UR – http://dx.doi.org/10.1038/ngeo2438
DO – 10.1038/ngeo2438
AB – Global mean surface warming has stalled since the end of the twentieth century1,2, but the net radiation imbalance at the top of the atmosphere continues to suggest an increasingly warming planet. This apparent contradiction has been reconciled by an anomalous heat flux into the ocean3,4,5,6,7,8, induced by a shift towards a La Niña-like state with cold sea surface temperatures in the eastern tropical Pacific over the past decade or so. A significant portion of the heat missing from the atmosphere is therefore expected to be stored in the Pacific Ocean. However, in situ hydrographic records indicate that Pacific Ocean heat content has been decreasing9. Here, we analyse observations along with simulations from a global ocean–sea ice model to track the pathway of heat. We find that the enhanced heat uptake by the Pacific Ocean has been compensated by an increased heat transport from the Pacific Ocean to the Indian Ocean, carried by the Indonesian throughflow. As a result, Indian Ocean heat content has increased abruptly, which accounts for more than 70% of the global ocean heat gain in the upper 700 m during the past decade. We conclude that the Indian Ocean has become increasingly important in modulating global climate variability.
ER –

NR – 157
TY – JOUR
AU – Roberts, C. D.
AU – Palmer, M. D.
AU – McNeall, D.
AU – Collins, M.
TI – Quantifying the likelihood of a continued hiatus in global warming
JF – Nature Climate Change
PY – 2015
VL – 5
SP – 337
UR – http://dx.doi.org/10.1038/nclimate2531
DO – 10.1038/nclimate2531
AB – Since the end of the twentieth century, global mean surface temperature has not risen as rapidly as predicted by global climate models1,2,3 (GCMs). This discrepancy has become known as the global warming ‘hiatus’ and a variety of mechanisms1,4,5,6,7,8,9,10,11,12,13,14,15,16,17 have been proposed to explain the observed slowdown in warming. Focusing on internally generated variability, we use pre-industrial control simulations from an observationally constrained ensemble of GCMs and a statistical approach to evaluate the expected frequency and characteristics of variability-driven hiatus periods and their likelihood of future continuation. Given an expected forced warming trend of ~0.2 K per decade, our constrained ensemble of GCMs implies that the probability of a variability-driven 10-year hiatus is ~10%, but less than 1% for a 20-year hiatus. Although the absolute probability of a 20-year hiatus is small, the probability that an existing 15-year hiatus will continue another five years is much higher (up to 25%). Therefore, given the recognized contribution of internal climate variability to the reduced rate of global warming during the past 15 years, we should not be surprised if the current hiatus continues until the end of the decade. Following the termination of a variability-driven hiatus, we also show that there is an increased likelihood of accelerated global warming associated with release of heat from the sub-surface ocean and a reversal of the phase of decadal variability in the Pacific Ocean.
ER –

NR – 158
TY – JOUR
AU – Notaro, Michael
AU – Yu, Yan
AU – Kalashnikova, Olga V.
TI – Regime shift in Arabian dust activity, triggered by persistent Fertile Crescent drought
JO – Journal of Geophysical Research: Atmospheres
VL – 120
IS – 19
UR – http://dx.doi.org/10.1002/2015JD023855
DO – 10.1002/2015JD023855
SP – 10,229
EP – 10,249
PY – 2015
AB – The Arabian Peninsula has experienced pronounced interannual to decadal variability in dust activity, including an abrupt regime shift around 2006 from an inactive dust period during 1998–2005 to an active period during 2007–2013. Corresponding in time to the onset of this regime shift, the climate state transitioned into a combined La Niña and negative phase of the Pacific Decadal Oscillation, which incited a hiatus in global warming in the 2000s. Superimposed upon a long-term regional drying trend, synergistic interactions between these teleconnection modes triggered the establishment of a devastating and prolonged drought, which engulfed the Fertile Crescent, namely, Iraq and Syria, and led to crop failure and civil unrest. Dried soils and diminished vegetation cover in the Fertile Crescent, as evident through remotely sensed enhanced vegetation indices, supported greater dust generation and transport to the Arabian Peninsula in 2007–2013, as identified both in increased dust days observed at weather stations and enhanced remotely sensed aerosol optical depth. According to backward trajectory analysis of dust days on the Arabian Peninsula, increased dust lifting and atmospheric dust concentration in the Fertile Crescent during this recent, prolonged drought episode supported a greater frequency of dust events across the peninsula with associated northerly trajectories and led to the dust regime shift. These findings are particularly concerning, considering projections of warming and drying for the eastern Mediterranean region and potential collapse of the Fertile Crescent during this century.
ER –

NR – 159
TY – JOUR
AU – Meehl, Gerald A.
AU – Teng, Haiyan
TI – Regional precipitation simulations for the mid-1970s shift and early-2000s hiatus
JO – Geophysical Research Letters
VL – 41
IS – 21
UR – http://dx.doi.org/10.1002/2014GL061778
DO – 10.1002/2014GL061778
SP – 7658
EP – 7665
PY – 2014
AB – It has been demonstrated that climate models initialized with observations produce better simulations of Pacific sea surface temperature (SST) patterns than uninitialized simulations for the two major climate regime changes of the last 40?years, the mid-1970s climate shift and early-2000s hiatus. A fundamental feature of these hindcasts is the simulation of the SST anomalies associated with the phase of the Interdecadal Pacific Oscillation (IPO). Since regional precipitation patterns over selected land areas in south Asia, Australia, and North America are known to be affected by SST patterns over the Pacific, it is shown that the initialized climate model simulations produce qualitatively better agreement with observations for regional precipitation anomalies in those regions compared to uninitialized climate models. Though the signals are small, the anomalies are consistent with our physical process-based understanding of precipitation responses over certain land areas during different IPO phases.
ER –

NR – 160
TY – JOUR
AU – Zhu, Yali
AU – Wang, Tao
AU – Wang, Huijun
PY – 2016
TI – Relative contribution of the anthropogenic forcing and natural variability to the interdecadal shift of climate during the late 1970s and 1990s
JO – Science Bulletin
SP – 416
EP – 424
VL – 61
IS – 5
AB – Global warming accelerated after the late 1970s and slowed down after the late 1990s, accompanying the significant interdecadal changes in the regional climate. We hypothesized that the interdecadal changes linearly consisted of two independent components, anthropogenic forcing and natural decadal variability, which can be represented simply by the radiative forcing effect of carbon dioxide (RF CO 2 ) (RFCO2) and the Pacific Decadal Oscillation (PDO), respectively. The combined effect of the RF CO 2 RFCO2 and PDO could explain the majority of the surface temperature changes during the late 1970s and 1990s, but the magnitudes of the relative contribution of the RF CO 2 RFCO2 and the PDO are inconsistent in different regions. For both the surface temperature and geopotential height, the RF CO 2 RFCO2 could induce significantly positive anomalies over almost the entire globe for these two shifts, exhibiting a larger magnitude in the mid–high latitudes and in the late 1990s shift. The PDO could induce opposite anomalies for the two interdecadal shifts due to its phase transitions (negative-positive–negative). Furthermore, for the shift in the late 1970s, both the RF CO 2 RFCO2 (53.7 %–66.7 %) and the PDO (33.3 %–46.3 %) were important in regulating the tropical geopotential height, whereas the RF CO 2 RFCO2 dominated the changes in the mid-latitudes. For the western Pacific subtropical high, the RF CO 2 RFCO2 (PDO) could explain 52.3 %–62.1 % (37.9 %–47.7 %) of the change. The negative effect of the PDO counteracted most of the RF CO 2 RFCO2 effects for the late 1990s shift.
UR – https://doi.org/10.1007/s11434-016-1012-3
DO – 10.1007/s11434-016-1012-3
ER –

NR – 161
TY – JOUR
AU – Song, Jinjie
AU – Wang, Yuan
AU – Tang, Jianping
TI – A Hiatus of the Greenhouse Effect
JF – Scientific Reports
PY – 2016
VL – 6
SP – 33315
UR – http://dx.doi.org/10.1038/srep33315
DO – 10.1038/srep33315
AB – The rate at which the global average surface temperature is increasing has slowed down since the end of the last century. This study investigates whether this warming hiatus results from a change in the well-known greenhouse effect. Using long-term, reliable, and consistent observational data from the Earth’s surface and the top of the atmosphere (TOA), two monthly gridded atmospheric and surface greenhouse effect parameters (Ga and Gs) are estimated to represent the radiative warming effects of the atmosphere and the surface in the infrared range from 1979 to 2014. The atmospheric and surface greenhouse effect over the tropical monsoon-prone regions is found to contribute substantially to the global total. Furthermore, the downward tendency of cloud activity leads to a greenhouse effect hiatus after the early 1990?s, prior to the warming pause. Additionally, this pause in the greenhouse effect is mostly caused by the high number of La Niña events between 1991 and 2014. A strong La Niña indicates suppressed convection in the tropical central Pacific that reduces atmospheric water vapor content and cloud volume. This significantly weakened regional greenhouse effect offsets the enhanced warming influence in other places and decelerates the rising global greenhouse effect. This work suggests that the greenhouse effect hiatus can be served as an additional factor to cause the recent global warming slowdown.
ER –

NR – 162
TY – JOUR
AU – Meehl, Gerald A.
AU – Arblaster, Julie M.
AU – Bitz, Cecilia M.
AU – Chung, Christine T. Y.
AU – Teng, Haiyan
TI – Antarctic sea-ice expansion between 2000 and 2014 driven by tropical Pacific decadal climate variability
JA – Nature Geoscience
PY – 2016
VL – 9
SP – 590
UR – http://dx.doi.org/10.1038/ngeo2751
DO – 10.1038/ngeo2751
AB – Antarctic sea-ice extent has been slowly increasing in the satellite record that began in 19791,2. Since the late 1990s, the increase has accelerated, but the average of all climate models shows a decline3. Meanwhile, the Interdecadal Pacific Oscillation, an internally generated mode of climate variability4, transitioned from positive to negative5, with an average cooling of tropical Pacific sea surface temperatures5, a slowdown of the global warming trend6,7,8 and a deepening of the Amundsen Sea Low near Antarctica1,9,10,11,12 that has contributed to regional circulation changes in the Ross Sea region and expansion of sea ice10. Here we show that the negative phase of the Interdecadal Pacific Oscillation in global coupled climate models is characterized by anomalies similar to the observed sea-level pressure and near-surface 850?hPa wind changes near Antarctica since 2000 that are conducive to expanding Antarctic sea-ice extent, particularly in the Ross Sea region in all seasons, involving a deepening of the Amundsen Sea Low. These atmospheric circulation changes are shown to be mainly driven by precipitation and convective heating anomalies related to the Interdecadal Pacific Oscillation in the equatorial eastern Pacific, with additional contributions from convective heating anomalies in the South Pacific convergence zone and tropical Atlantic regions.
ER –

NR – 163
TY – JOUR
T1 – Atlantic and Pacific multidecadal oscillations and Northern Hemisphere temperatures
JF – Science
SP – 988
LP – 991
DO – 10.1126/science.1257856
VL – 347
IS – 6225
AU – Steinman, Byron A.
AU – Mann, Michael E.
AU – Miller, Sonya K.
PY – 2015
UR – http://science.sciencemag.org/content/347/6225/988.abstract
AB – Which recent climate changes have been forced by greenhouse gas emissions, and which have been natural fluctuations of the climate system? Steinman et al. combined observational data and a large collection of climate models to assess the Northern Hemisphere climate over the past 150 years (see the Perspective by Booth). At various points in time, the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation have played particularly large roles in producing temperature trends. Their effects have combined to cause the apparent pause in warming at the beginning of the 21st century, known as the warming “hiatus.” This pause is projected to end in the near future as temperatures resume their upward climb.Science, this issue p. 988; see also p. 952 The recent slowdown in global warming has brought into question the reliability of climate model projections of future temperature change and has led to a vigorous debate over whether this slowdown is the result of naturally occurring, internal variability or forcing external to Earth’s climate system. To address these issues, we applied a semi-empirical approach that combines climate observations and model simulations to estimate Atlantic- and Pacific-based internal multidecadal variability (termed “AMO” and “PMO,” respectively). Using this method, the AMO and PMO are found to explain a large proportion of internal variability in Northern Hemisphere mean temperatures. Competition between a modest positive peak in the AMO and a substantially negative-trending PMO are seen to produce a slowdown or “false pause” in warming of the past decade.
ER –

NR – 164
TY – JOUR
AU – Visbeck, Martin
TI – Bumpy path to a warmer world
JA – Nature Geoscience
PY – 2014
VL – 7
SP – 160
UR – http://dx.doi.org/10.1038/ngeo2104
DO – 10.1038/ngeo2104
AB – Decadal climate variability has long received limited attention. With the slow-down in surface warming since the late 1990s, the decadal scale has rightly become a focus of attention: for assessing climate change and its impacts, it is of critical importance.
ER –

NR – 165
TY – JOUR
AU – Meehl, Gerald A.
AU – Hu, Aixue
AU – Santer, Benjamin D.
AU – Xie, Shang-Ping
TI – Contribution of the Interdecadal Pacific Oscillation to twentieth-century global surface temperature trends
JF – Nature Climate Change
PY – 2016
VL – 6
SP – 1005
UR – http://dx.doi.org/10.1038/nclimate3107
DO – 10.1038/nclimate3107
AB – Longer-term externally forced trends in global mean surface temperatures (GMSTs) are embedded in the background noise of internally generated multidecadal variability1. A key mode of internal variability is the Interdecadal Pacific Oscillation (IPO), which contributed to a reduced GMST trend during the early 2000s1,2,3. We use a novel, physical phenomenon-based approach to quantify the contribution from a source of internally generated multidecadal variability—the IPO—to multidecadal GMST trends. Here we show that the largest IPO contributions occurred in its positive phase during the rapid warming periods from 1910–1941 and 1971–1995, with the IPO contributing 71% and 75%, respectively, to the difference between the median values of the externally forced trends and observed trends. The IPO transition from positive to negative in the late-1990s contributed 27% of the discrepancy between model median estimates of the forced part of the GMST trend and the observed trend from 1995 to 2013, with additional contributions that are probably due to internal variability outside of the Pacific4 and an externally forced response from small volcanic eruptions5. Understanding and quantifying the contribution of a specific source of internally generated variability—the IPO—to GMST trends is necessary to improve decadal climate prediction skill.
ER –

NR – 166
TY – JOUR
AU – Balmaseda, Magdalena A.
AU – Trenberth, Kevin E.
AU – Källén, Erland
TI – Distinctive climate signals in reanalysis of global ocean heat content
JO – Geophysical Research Letters
VL – 40
IS – 9
UR – http://dx.doi.org/10.1002/grl.50382
DO – 10.1002/grl.50382
SP – 1754
EP – 1759
PY – 2013
AB – The elusive nature of the post-2004 upper ocean warming has exposed uncertainties in the ocean’s role in the Earth’s energy budget and transient climate sensitivity. Here we present the time evolution of the global ocean heat content for 1958 through 2009 from a new observation-based reanalysis of the ocean. Volcanic eruptions and El Niño events are identified as sharp cooling events punctuating a long-term ocean warming trend, while heating continues during the recent upper-ocean-warming hiatus, but the heat is absorbed in the deeper ocean. In the last decade, about 30% of the warming has occurred below 700 m, contributing significantly to an acceleration of the warming trend. The warming below 700 m remains even when the Argo observing system is withdrawn although the trends are reduced. Sensitivity experiments illustrate that surface wind variability is largely responsible for the changing ocean heat vertical distribution.
ER –

NR – 167
TY – JOUR
AU – Johansson, Daniel J. A.
AU – O’Neill, Brian C.
AU – Tebaldi, Claudia
AU – Häggström, Olle
TI – Equilibrium climate sensitivity in light of observations over the warming hiatus
JF – Nature Climate Change
PY – 2015
VL – 5
SP – 449
UR – http://dx.doi.org/10.1038/nclimate2573
DO – 10.1038/nclimate2573
AB – A key uncertainty in projecting future climate change is the magnitude of equilibrium climate sensitivity (ECS), that is, the eventual increase in global annual average surface temperature in response to a doubling of atmospheric CO2 concentration. The lower bound of the likely range for ECS given in the IPCC Fifth Assessment Report (AR5; refs 1, 2) was revised downwards to 1.5 °C, from 2 °C in its previous report3, mainly as an effect of considering observations over the warming hiatus—the period of slowdown of global average temperature increase since the early 2000s. Here we analyse how estimates of ECS change as observations accumulate over time and estimate the contribution of potential causes to the hiatus. We find that including observations over the hiatus reduces the most likely value for ECS from 2.8 °C to 2.5 °C, but that the lower bound of the 90% range remains stable around 2 °C. We also find that the hiatus is primarily attributable to El Niño/Southern Oscillation-related variability and reduced solar forcing.
ER –

NR – 168
TY – JOUR
A1 – Schleussner, C. F.
A1 – Runge, J.
A1 – Lehmann, J.
A1 – Levermann, A.
T1 – The role of the North Atlantic overturning and deep ocean for multi-decadal global-mean-temperature variability
JA – Earth Syst. Dynam.
VL – 5
IS – 1
SP – 103
EP – 115
PY – 2014
UR – https://www.earth-syst-dynam.net/5/103/2014/
DO – 10.5194/esd-5-103-2014
AB – Earth’s climate exhibits internal modes of variability on various timescales. Here we investigate multi-decadal variability of the Atlantic meridional overturning circulation (AMOC), Northern Hemisphere sea-ice extent and global mean temperature (GMT) in an ensemble of CMIP5 models under control conditions. We report an inter-annual GMT variability of about ±0.1° C originating solely from natural variability in the model ensemble. By decomposing the GMT variance into contributions of the AMOC and Northern Hemisphere sea-ice extent using a graph-theoretical statistical approach, we find the AMOC to contribute 8% to GMT variability in the ensemble mean. Our results highlight the importance of AMOC sea-ice feedbacks that explain 5% of the GMT variance, while the contribution solely related to the AMOC is found to be about 3%. As a consequence of multi-decadal AMOC variability, we report substantial variations in North Atlantic deep-ocean heat content with trends of up to 0.7 × 1022 J decade-1 that are of the order of observed changes over the last decade and consistent with the reduced GMT warming trend over this period. Although these temperature anomalies are largely density-compensated by salinity changes, we find a robust negative correlation between the AMOC and North Atlantic deep-ocean density with density lagging the AMOC by 5 to 11 yr in most models. While this would in principle allow for a self-sustained oscillatory behavior of the coupled AMOC–deep- ocean system, our results are inconclusive about the role of this feedback in the model ensemble.
ER –

NR – 169
TY – JOUR
T1 – Extratropical Ocean Warming and Winter Arctic Sea Ice Cover since the 1990s
AU – Li, Fei
AU – Wang, Huijun
AU – Gao, Yongqi
PY – 2015
DO – 10.1175/JCLI-D-14-00629.1
JF – Journal of Climate
SP – 5510
EP – 5522
VL – 28
IS – 14
AB – Despite the fact that the Arctic Oscillation (AO) has reached a more neutral state and a global-warming hiatus has occurred in winter since the late 1990s, the Arctic sea ice cover (ASIC) still shows a pronounced decrease. This study reveals a close connection (R = 0.5) between the extratropical sea surface temperature (ET-SST) and ASIC in winter from 1994 to 2013. In response to one positive (negative) unit of deviation in the ET-SST pattern, the ASIC decreases (increases) in the Barents?Kara Seas and Hudson Bay (the Baffin Bay and Bering Sea) by 100?400 km2. This relationship might be maintained because of the impact of warming extratropical oceans on the polar vortex. Positive SST anomalies in the midlatitudes of the North Pacific and Atlantic (around 40°N) strengthen the equatorward planetary wave propagation, whereas negative SST anomalies in the high latitudes weaken the upward planetary wave propagation from the lower troposphere to the stratosphere. The former indicates a strengthening of the poleward meridional eddy momentum flux, and the latter implies a weakening of the poleward eddy heat flux, which favors an intensified upper-level polar night jet and a colder polar vortex, implying a stronger-than-normal polar vortex. Consequently, an anomalous cyclone emerges over the eastern Arctic, limiting or encouraging the ASIC by modulating the mean meridional heat flux. A possible reason for the long-term changes in the relationship between the ET-SST and ASIC is also discussed.
M3 – doi: 10.1175/JCLI-D-14-00629.1
UR – https://doi.org/10.1175/JCLI-D-14-00629.1
ER –

NR – 170
TY – JOUR
AU – Zhou, Yu
AU – Luo, Ming
AU – Leung, Yee
TI – On the detection of precipitation dependence on temperature
JO – Geophysical Research Letters
VL – 43
IS – 9
UR – http://dx.doi.org/10.1002/2016GL068811
DO – 10.1002/2016GL068811
SP – 4555
EP – 4565
PY – 2016
AB – Employing their newly proposed interannual difference method (IADM), Liu et al. (2009) and Shiu et al. (2012) reported a shocking increase of around 100% K-1 in heavy precipitation with warming global temperature in 1979–2007. Such increase is alarming and prompts us to probe into the IADM. In this study, both analytical derivations and numerical analyses demonstrate that IADM provides no additional information to that of the conventional linear regression, and also, it may give a false indication of dependence. For clarity and simplicity, we therefore recommend linear regression analysis over the IADM for the detection of dependence. We also find that heavy precipitation decreased during the global warming hiatus, and the precipitation dependence on temperature drops by almost 50% when the study period is extended to 1979–2014 and it may keep dropping in the near future. The risk of having heavy precipitation under warming global temperature may have been overestimated.
ER –

NR – 171
TY – JOUR
AU – Mann, Michael E.
AU – Steinman, Byron A.
AU – Miller, Sonya K.
AU – Frankcombe, Leela M.
AU – England, Matthew H.
AU – Cheung, Anson H.
TI – Predictability of the recent slowdown and subsequent recovery of large-scale surface warming using statistical methods
JO – Geophysical Research Letters
VL – 43
IS – 7
UR – http://dx.doi.org/10.1002/2016GL068159
DO – 10.1002/2016GL068159
SP – 3459
EP – 3467
PY – 2016
AB – The temporary slowdown in large-scale surface warming during the early 2000s has been attributed to both external and internal sources of climate variability. Using semiempirical estimates of the internal low-frequency variability component in Northern Hemisphere, Atlantic, and Pacific surface temperatures in concert with statistical hindcast experiments, we investigate whether the slowdown and its recent recovery were predictable. We conclude that the internal variability of the North Pacific, which played a critical role in the slowdown, does not appear to have been predictable using statistical forecast methods. An additional minor contribution from the North Atlantic, by contrast, appears to exhibit some predictability. While our analyses focus on combining semiempirical estimates of internal climatic variability with statistical hindcast experiments, possible implications for initialized model predictions are also discussed.
ER –

NR – 172
TY – JOUR
AU – You, Qinglong
AU – Min, Jinzhong
AU – Kang, Shichang
TI – Rapid warming in the Tibetan Plateau from observations and CMIP5 models in recent decades
JO – International Journal of Climatology
VL – 36
IS – 6
UR – http://dx.doi.org/10.1002/joc.4520
DO – 10.1002/joc.4520
SP – 2660
EP – 2670
PY – 2016
AB – On the basis of mean temperature, maximum temperature and minimum temperature from the updated China Homogenized Historical Temperature Data Sets, the recent warming in the Tibetan Plateau (TP) during 1961–2005 and global warming hiatus period are examined. During 1961–2005, the mean temperature, maximum temperature and minimum temperature in the whole TP show a statistically increasing trend especially after the 1980s, with the annual rates of 0.27, 0.19 and 0.36 °C decade-1, respectively. The performance of 26 general circulation models (GCMs) available in the fifth phase of the Coupled Model Intercomparison Project (CMIP5) is evaluated in the TP by comparison with the observations during 1961–2005. Most CMIP5 GCMs can capture the decadal variations of the observed mean temperature, maximum temperature and minimum temperature, and have significant positive correlations with observations (R > 0.5), with root mean squared error 1500m. The Hilbert spectrum from the OHC in the Labrador Sea interior reveals two important components at frequencies of 0.8-1.2cycleyr-1 (T=0.8–1.25 years) and 0.1-0.3cycleyr-1 (T=3.3–10 years), respectively, superimposed on the warming trends. The former corresponds to the dominant seasonal cycle due to surface heating, while the latter is concomitant with the timing of the reoccurrence of convective events. We also found that the cumulative North Atlantic Oscillation (NAO) index significantly correlates to the low-frequency OHC variations. Therefore, the interannual signals in the Labrador Sea at especially the intermediate layers are attributed to changes in the deep convective processes and the atmospheric conditions. By comparing with an extended OHC record (1945–2010), it was further shown that the warming trends obtained from the 10-year Argo record are part of multi-decadal variations that presumably reflect the Atlantic Multi-decadal Oscillation (AMO). In addition, the recent OHC changes in the Labrador Sea (i.e., increased heat in the deeper layers) may be related to the current global warming hiatus, suggesting the potential contributions from the Atlantic Meridional Overturning Circulation (AMOC) to the low-frequency OHC in the Labrador Sea.
ER –

NR – 173
TY – JOUR
AU – Beniston, Martin
PY – 2015
TI – Ratios of record high to record low temperatures in Europe exhibit sharp increases since 2000 despite a slowdown in the rise of mean temperatures
JO – Climatic Change
SP – 225
EP – 237
VL – 129
IS – 1
AB – A study has been undertaken to analyze the behavior of record high and low values of temperature since the early 1950s for 30 locations spread across Europe. When establishing the ratios of the number of record Tmax to record Tmin values in each year, it is seen that there is a sharp increase in these ratios in the most recent decade. This seems to be an apparent paradox in view of the slow-down in atmospheric temperatures that has been observed since the early 2000s at both the hemispheric and European scales, but closer analysis suggests that the relationship between the record high:low ratios and mean annual temperatures is not linear but rather a square relationship. It is suggested that the record high to record low ratios in both the Mediterranean region and beyond 60° latitude north, observed in the most recent decade, may be related to an amplification of low-level atmospheric temperatures resulting from shorter snow seasons in the north and enhanced summer dryness in the south.
UR – https://doi.org/10.1007/s10584-015-1325-2
DO – 10.1007/s10584-015-1325-2
ER –

NR – 174
TY – JOUR
T1 – Decadal Climate Prediction: An Update from the Trenches
AU – Meehl, Gerald A.
AU – Goddard, Lisa
AU – Boer, George
AU – Burgman, Robert
AU – Branstator, Grant
AU – Cassou, Christophe
AU – Corti, Susanna
AU – Danabasoglu, Gokhan
AU – Doblas-Reyes, Francisco
AU – Hawkins, Ed
AU – Karspeck, Alicia
AU – Kimoto, Masahide
AU – Kumar, Arun
AU – Matei, Daniela
AU – Mignot, Juliette
AU – Msadek, Rym
AU – Navarra, Antonio
AU – Pohlmann, Holger
AU – Rienecker, Michele
AU – Rosati, Tony
AU – Schneider, Edwin
AU – Smith, Doug
AU – Sutton, Rowan
AU – Teng, Haiyan
AU – van Oldenborgh, Geert Jan
AU – Vecchi, Gabriel
AU – Yeager, Stephen
PY – 2013
DO – 10.1175/BAMS-D-12-00241.1
JF – Bulletin of the American Meteorological Society
SP – 243
EP – 267
VL – 95
IS – 2
AB – This paper provides an update on research in the relatively new and fast-moving field of decadal climate prediction, and addresses the use of decadal climate predictions not only for potential users of such information but also for improving our understanding of processes in the climate system. External forcing influences the predictions throughout, but their contributions to predictive skill become dominant after most of the improved skill from initialization with observations vanishes after about 6?9 years. Recent multimodel results suggest that there is relatively more decadal predictive skill in the North Atlantic, western Pacific, and Indian Oceans than in other regions of the world oceans. Aspects of decadal variability of SSTs, like the mid-1970s shift in the Pacific, the mid-1990s shift in the northern North Atlantic and western Pacific, and the early-2000s hiatus, are better represented in initialized hindcasts compared to uninitialized simulations. There is evidence of higher skill in initialized multimodel ensemble decadal hindcasts than in single model results, with multimodel initialized predictions for near-term climate showing somewhat less global warming than uninitialized simulations. Some decadal hindcasts have shown statistically reliable predictions of surface temperature over various land and ocean regions for lead times of up to 6?9 years, but this needs to be investigated in a wider set of models. As in the early days of El Niño?Southern Oscillation (ENSO) prediction, improvements to models will reduce the need for bias adjustment, and increase the reliability, and thus usefulness, of decadal climate predictions in the future.
M3 – doi: 10.1175/BAMS-D-12-00241.1
UR – https://doi.org/10.1175/BAMS-D-12-00241.1
ER –

NR – 175
TY – JOUR
AU – Thoma, Malte
AU – Greatbatch, Richard J.
AU – Kadow, Christopher
AU – Gerdes, Ruediger
TI – Decadal hindcasts initialized using observed surface wind stress: Evaluation and prediction out to 2024
JO – Geophysical Research Letters
VL – 42
IS – 15
UR – http://dx.doi.org/10.1002/2015GL064833
DO – 10.1002/2015GL064833
SP – 6454
EP – 6461
PY – 2015
AB – We use surface air temperature to evaluate the decadal forecast skill of the fully coupled Max Planck Institut Earth System Model (MPI-ESM) initialized using only surface wind stress applied to the ocean component of the model (Modini: Model initialization by partially coupled spin-up). Our analysis shows that the greenhouse gas forcing alone results in a significant forecast skill on the 2–5 and 6–9 year range even for uninitialized hindcasts. For the first forecast year, the forecast skill of Modini is generally comparable with previous initialization procedures applied to MPI-ESM. But only Modini is able to generate a significant skill (correlation) in the tropical Pacific for a 2–5 year (and to a lesser extent for a 6–9 year) hindcast. Modini is also better able to capture the observed hiatus in global warming in hindcast mode than the other methods. Finally, we present forecasts for 2015 and the average of years 2016–2019 and 2020–2024, predicting an end to the hiatus.
ER –

NR – 176
TY – JOUR
A1 – Boer, G. J.
A1 – Smith, D. M.
A1 – Cassou, C.
A1 – Doblas-Reyes, F.
A1 – Danabasoglu, G.
A1 – Kirtman, B.
A1 – Kushnir, Y.
A1 – Kimoto, M.
A1 – Meehl, G. A.
A1 – Msadek, R.
A1 – Mueller, W. A.
A1 – Taylor, K. E.
A1 – Zwiers, F.
A1 – Rixen, M.
A1 – Ruprich-Robert, Y.
A1 – Eade, R.
T1 – The Decadal Climate Prediction Project (DCPP) contribution to CMIP6
JA – Geosci. Model Dev.
VL – 9
IS – 10
SP – 3751
EP – 3777
PY – 2016
UR – https://www.geosci-model-dev.net/9/3751/2016/
DO – 10.5194/gmd-9-3751-2016
AB – The Decadal Climate Prediction Project (DCPP) is a coordinated multi-model investigation into decadal climate prediction, predictability, and variability. The DCPP makes use of past experience in simulating and predicting decadal variability and forced climate change gained from the fifth Coupled Model Intercomparison Project (CMIP5) and elsewhere. It builds on recent improvements in models, in the reanalysis of climate data, in methods of initialization and ensemble generation, and in data treatment and analysis to propose an extended comprehensive decadal prediction investigation as a contribution to CMIP6 (Eyring et al., 2016) and to the WCRP Grand Challenge on Near Term Climate Prediction (Kushnir et al., 2016). The DCPP consists of three components. Component A comprises the production and analysis of an extensive archive of retrospective forecasts to be used to assess and understand historical decadal prediction skill, as a basis for improvements in all aspects of end-to-end decadal prediction, and as a basis for forecasting on annual to decadal timescales. Component B undertakes ongoing production, analysis and dissemination of experimental quasi-real-time multi-model forecasts as a basis for potential operational forecast production. Component C involves the organization and coordination of case studies of particular climate shifts and variations, both natural and naturally forced (e.g. the “hiatus”, volcanoes), including the study of the mechanisms that determine these behaviours. Groups are invited to participate in as many or as few of the components of the DCPP, each of which are separately prioritized, as are of interest to them. The Decadal Climate Prediction Project addresses a range of scientific issues involving the ability of the climate system to be predicted on annual to decadal timescales, the skill that is currently and potentially available, the mechanisms involved in long timescale variability, and the production of forecasts of benefit to both science and society.
ER –

NR – 177
TY – JOUR
AU – Smith, Doug M.
AU – Allan, Richard P.
AU – Coward, Andrew C.
AU – Eade, Rosie
AU – Hyder, Patrick
AU – Liu, Chunlei
AU – Loeb, Norman G.
AU – Palmer, Matthew D.
AU – Roberts, Chris D.
AU – Scaife, Adam A.
TI – Earth’s energy imbalance since 1960 in observations and CMIP5 models
JO – Geophysical Research Letters
VL – 42
IS – 4
UR – http://dx.doi.org/10.1002/2014GL062669
DO – 10.1002/2014GL062669
SP – 1205
EP – 1213
PY – 2015
AB – Observational analyses of running 5 year ocean heat content trends (Ht) and net downward top of atmosphere radiation (N) are significantly correlated (r?~?0.6) from 1960 to 1999, but a spike in Ht in the early 2000s is likely spurious since it is inconsistent with estimates of N from both satellite observations and climate model simulations. Variations in N between 1960 and 2000 were dominated by volcanic eruptions and are well simulated by the ensemble mean of coupled models from the Fifth Coupled Model Intercomparison Project (CMIP5). We find an observation-based reduction in N of -? 0.31?±?0.21?W?m-2 between 1999 and 2005 that potentially contributed to the recent warming slowdown, but the relative roles of external forcing and internal variability remain unclear. While present-day anomalies of N in the CMIP5 ensemble mean and observations agree, this may be due to a cancelation of errors in outgoing longwave and absorbed solar radiation.
ER –

NR – 178
TY – JOUR
A1 – Piecuch, C. G.
A1 – Quinn, K. J.
T1 – El Niño, La Niña, and the global sea level budget
JA – Ocean Sci.
VL – 12
IS – 6
SP – 1165
EP – 1177
PY – 2016
UR – https://www.ocean-sci.net/12/1165/2016/
DO – 10.5194/os-12-1165-2016
AB – Previous studies show that nonseasonal variations in global-mean sea level (GMSL) are significantly correlated with El Niño–Southern Oscillation (ENSO). However, it has remained unclear to what extent these ENSO-related GMSL fluctuations correspond to steric (i.e., density) or barystatic (mass) effects. Here we diagnose the GMSL budget for ENSO events observationally using data from profiling floats, satellite gravimetry, and radar altimetry during 2005–2015. Steric and barystatic effects make comparable contributions to the GMSL budget during ENSO, in contrast to previous interpretations based largely on hydrological models, which emphasize the barystatic component. The steric contributions reflect changes in global ocean heat content, centered on the Pacific. Distributions of ocean heat storage in the Pacific arise from a mix of diabatic and adiabatic effects. Results have implications for understanding the surface warming slowdown and demonstrate the usefulness of the Global Ocean Observing System for constraining Earth’s hydrological cycle and radiation imbalance.
ER –

NR – 179
TY – JOUR
T1 – Varying temperature and heat content signatures in the central Labrador Sea at different layers and timescales
AU – Li, Feili
AU – Jo, Young-Heon
AU – Yan, Xiao-Hai
AU – Timothy Liu, W.
JO – Deep Sea Research Part I: Oceanographic Research Papers
VL – 103
SP – 114
EP – 124
PY – 2015
DO – https://doi.org/10.1016/j.dsr.2015.04.012
UR – http://www.sciencedirect.com/science/article/pii/S0967063715000862
AB – The dominant modes of variability in the temperature and ocean heat content (OHC; 0–1000m) of the central Labrador Sea were investigated using the Hilbert–Huang Transform (HHT) based on Argo profiles collected during 2003–2012. Warming trends of approximately 0.03°Cyr-1 were observed in the upper 2000m of the water column. A strong annual temperature cycle exists and dominates at the 500m depth, while signals at the interannual timescales can explain most of the temperature variability at the 1000m and 1500m depths. These interannual signals are closely correlated to the variability of deep convection in the Labrador Sea, which has intermittent enhancement of mixed layer depth (MLD)>1500m. The Hilbert spectrum from the OHC in the Labrador Sea interior reveals two important components at frequencies of 0.8-1.2cycleyr-1 (T=0.8–1.25 years) and 0.1-0.3cycleyr-1 (T=3.3–10 years), respectively, superimposed on the warming trends. The former corresponds to the dominant seasonal cycle due to surface heating, while the latter is concomitant with the timing of the reoccurrence of convective events. We also found that the cumulative North Atlantic Oscillation (NAO) index significantly correlates to the low-frequency OHC variations. Therefore, the interannual signals in the Labrador Sea at especially the intermediate layers are attributed to changes in the deep convective processes and the atmospheric conditions. By comparing with an extended OHC record (1945–2010), it was further shown that the warming trends obtained from the 10-year Argo record are part of multi-decadal variations that presumably reflect the Atlantic Multi-decadal Oscillation (AMO). In addition, the recent OHC changes in the Labrador Sea (i.e., increased heat in the deeper layers) may be related to the current global warming hiatus, suggesting the potential contributions from the Atlantic Meridional Overturning Circulation (AMOC) to the low-frequency OHC in the Labrador Sea.
ER –

NR – 180
TY – JOUR
T1 – Very early warning of next El Niño
JF – Proceedings of the National Academy of Sciences
SP – 2064
LP – 2066
DO – 10.1073/pnas.1323058111
VL – 111
IS – 6
AU – Ludescher, Josef
AU – Gozolchiani, Avi
AU – Bogachev, Mikhail I.
AU – Bunde, Armin
AU – Havlin, Shlomo
AU – Schellnhuber, Hans Joachim
PY – 2014
UR – http://www.pnas.org/content/111/6/2064.abstract
AB – The most important driver of climate variability is the El Niño Southern Oscillation, which can trigger disasters in various parts of the globe. Despite its importance, conventional forecasting is still limited to 6 mo ahead. Recently, we developed an approach based on network analysis, which allows projection of an El Niño event about 1 y ahead. Here we show that our method correctly predicted the absence of El Niño events in 2012 and 2013 and now announce that our approach indicated (in September 2013 already) the return of El Niño in late 2014 with a 3-in-4 likelihood. We also discuss the relevance of the next El Niño to the question of global warming and the present hiatus in the global mean surface temperature.
ER –

NR – 181
TY – JOUR
AU – Laepple, T.
AU – Huybers, P.
TI – Global and regional variability in marine surface temperatures
JO – Geophysical Research Letters
VL – 41
IS – 7
UR – http://dx.doi.org/10.1002/2014GL059345
DO – 10.1002/2014GL059345
SP – 2528
EP – 2534
PY – 2014
AB – The temperature variability simulated by climate models is generally consistent with that observed in instrumental records at the scale of global averages, but further insight can also be obtained from regional analysis of the marine temperature record. A protocol is developed for comparing model simulations to observations that account for observational noise and missing data. General consistency between Coupled Model Intercomparison Project Phase 5 model simulations and regional sea surface temperature variability is demonstrated at interannual timescales. At interdecadal timescales, however, the variability diagnosed from observations is significantly greater. Discrepancies are greatest at low latitudes, with none of the 41 models showing equal or greater interdecadal variability. The pattern of suppressed variability at longer timescales and smaller spatial scales appears consistent with models generally being too diffusive. Suppressed variability of low-latitude marine temperatures points to underestimation of intrinsic variability and may help explain why few models reproduce the observed temperature trends during the last 15?years.
ER –

NR – 182
TY – JOUR
AU – de Boisséson, E.
AU – Balmaseda, M. A.
AU – Abdalla, S.
AU – Källén, E.
AU – Janssen, P. A. E. M.
TI – How robust is the recent strengthening of the Tropical Pacific trade winds?
JO – Geophysical Research Letters
VL – 41
IS – 12
UR – http://dx.doi.org/10.1002/2014GL060257
DO – 10.1002/2014GL060257
SP – 4398
EP – 4405
PY – 2014
AB – The persistent strengthening of the trade winds over the Pacific Ocean over the past 20 years has recently been proposed as a driver for the increase of ocean heat uptake linked to the hiatus in surface global warming. Crucial aspects in this argument are the reliability of the wind signal, usually derived from atmospheric reanalyses, and the ability of models to represent it. This study addresses these two aspects by comparing various observations with reanalyses and model integrations from the European Centre for Medium-Range Weather Forecasts system. We show that the strengthening of trades over the Pacific is a robust feature in several observational data sets as well as in the reanalyses based on full and limited sets of observations. The wind trend is also reproduced in an atmospheric model integration forced by sea surface temperature analysis, a result that opens the doors to further investigation on the nature of the changes.
ER –

NR – 183
TY – JOUR
AU – Gleckler, Peter J.
AU – Durack, Paul J.
AU – Stouffer, Ronald J.
AU – Johnson, Gregory C.
AU – Forest, Chris E.
TI – Industrial-era global ocean heat uptake doubles in recent decades
JF – Nature Climate Change
PY – 2016
VL – 6
SP – 394
UR – http://dx.doi.org/10.1038/nclimate2915
DO – 10.1038/nclimate2915
AB – Formal detection and attribution studies have used observations and climate models to identify an anthropogenic warming signature in the upper (0–700?m) ocean1,2,3,4. Recently, as a result of the so-called surface warming hiatus, there has been considerable interest in global ocean heat content (OHC) changes in the deeper ocean, including natural and anthropogenically forced changes identified in observational5,6,7, modelling8,9 and data re- analysis10,11 studies. Here, we examine OHC changes in the context of the Earth’s global energy budget since early in the industrial era (circa 1865– 2015) for a range of depths. We rely on OHC change estimates from a diverse collection of measurement systems including data from the nineteenth-century Challenger expedition12, a multi-decadal record of ship-based in situ mostly upper-ocean measurements, the more recent near-global Argo floats profiling to intermediate (2,000?m) depths13, and full-depth repeated transoceanic sections5. We show that the multi-model mean constructed from the current generation of historically forced climate models is consistent with the OHC changes from this diverse collection of observational systems. Our model- based analysis suggests that nearly half of the industrial-era increases in global OHC have occurred in recent decades, with over a third of the accumulated heat occurring below 700?m and steadily rising.
ER –

NR – 184
TY – JOUR
AU – Liu, Qin-Yan
AU – Feng, Ming
AU – Wang, Dongxiao
AU – Wijffels, Susan
TI – Interannual variability of the Indonesian Throughflow transport: A revisit based on 30 year expendable bathythermograph data
JO – Journal of Geophysical Research: Oceans
VL – 120
IS – 12
UR – http://dx.doi.org/10.1002/2015JC011351
DO – 10.1002/2015JC011351
SP – 8270
EP – 8282
PY – 2015
AB – Based on 30 year repeated expendable bathythermograph (XBT) deployments between Fremantle, Western Australia, and the Sunda Strait, Indonesia, from 1984 to 2013, interannual variability of geostrophic transport of the Indonesian Throughflow (ITF) and its relationships with El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) are investigated. The IOD induced coastal Kelvin waves propagate along the Sumatra-Java coast of Indonesia, and ENSO induced coastal Kelvin waves propagate along the northwest coast of Australia, both influencing interannual variations of the ITF transport. The ITF geostrophic transport is stronger during La Niña phase and weaker during El Niño phase, with the Niño3.4 index leading the ITF variability by 7 months. The Indian Ocean wind variability associated with the IOD to a certain extent offset the Pacific ENSO influences on the ITF geostrophic transport during the developing and mature phases of El Niño and La Niña, due to the covarying IOD variability with ENSO. The ITF geostrophic transport experiences a strengthening trend of about 1 Sv every 10 years over the study period, which is mostly due to a response to the strengthening of the trade winds in the Pacific during the climate change hiatus period. Decadal variations of the temperature-salinity relationships need to be considered when estimating the geostrophic transport of the ITF using XBT data.
ER –

NR – 185
TY – JOUR
AU – Li, Jianping
AU – Sun, Cheng
AU – Jin, Fei-Fei
TI – NAO implicated as a predictor of Northern Hemisphere mean temperature multidecadal variability
JO – Geophysical Research Letters
VL – 40
IS – 20
UR – http://dx.doi.org/10.1002/2013GL057877
DO – 10.1002/2013GL057877
SP – 5497
EP – 5502
PY – 2013
AB – The twentieth century Northern Hemisphere mean surface temperature (NHT) is characterized by a multidecadal warming-cooling-warming pattern followed by a flat trend since about 2000 (recent warming hiatus). Here we demonstrate that the North Atlantic Oscillation (NAO) is implicated as a useful predictor of NHT multidecadal variability. Observational analysis shows that the NAO leads both the detrended NHT and oceanic Atlantic Multidecadal Oscillation (AMO) by 15–20?years. Theoretical analysis illuminates that the NAO precedes NHT multidecadal variability through its delayed effect on the AMO due to the large thermal inertia associated with slow oceanic processes. An NAO-based linear model is therefore established to predict the NHT, which gives an excellent hindcast for NHT in 1971–2011 with the recent flat trend well predicted. NHT in 2012–2027 is predicted to fall slightly over the next decades, due to the recent NAO decadal weakening that temporarily offsets the anthropogenically induced warming.
ER –

NR – 186
TY – JOUR
T1 – Northwestern Pacific typhoon intensity controlled by changes in ocean temperatures
JF – Science Advances
DO – 10.1126/sciadv.1500014
VL – 1
IS – 4
AU – Mei, Wei
AU – Xie, Shang-Ping
AU – Primeau, François
AU – McWilliams, James C.
AU – Pasquero, Claudia
PY – 2015
UR – http://advances.sciencemag.org/content/1/4/e1500014.abstract
AB – Dominant climatic factors controlling the lifetime peak intensity of typhoons are determined from six decades of Pacific typhoon data. We find that upper ocean temperatures in the low-latitude northwestern Pacific (LLNWP) and sea surface temperatures in the central equatorial Pacific control the seasonal average lifetime peak intensity by setting the rate and duration of typhoon intensification, respectively. An anomalously strong LLNWP upper ocean warming has favored increased intensification rates and led to unprecedentedly high average typhoon intensity during the recent global warming hiatus period, despite a reduction in intensification duration tied to the central equatorial Pacific surface cooling. Continued LLNWP upper ocean warming as predicted under a moderate [that is, Representative Concentration Pathway (RCP) 4.5] climate change scenario is expected to further increase the average typhoon intensity by an additional 14% by 2100.
ER –

NR – 187
TY – JOUR
AU – Takahashi, Chiharu
AU – Watanabe, Masahiro
TI – Pacific trade winds accelerated by aerosol forcing over the past two decades
JF – Nature Climate Change
PY – 2016
VL – 6
SP – 768
UR – http://dx.doi.org/10.1038/nclimate2996
DO – 10.1038/nclimate2996
AB – The Pacific trade winds, coupled with the zonal sea surface temperature gradient in the equatorial Pacific Ocean, control regional sea levels1, and therefore their trend is a great concern in the Pacific Rim. Over the past two decades, easterly winds have been accelerated in association with eastern tropical Pacific cooling2. They may represent natural interdecadal variability in the Pacific3 and possibly explain the recent global warming hiatus4,5,6,7. However, the intensification of the winds has been the strongest ever observed in the past century2,5,8, the reason for which is still unclear. Here we show, using multiple climate simulations for 1921–2014 by a global climate model, that approximately one-third of the trade-wind intensification for 1991–2010 can be attributed to changes in sulfate aerosols. The multidecadal sea surface temperature anomaly induced mostly by volcanic aerosols dominates in the western North Pacific, and its sign changed rapidly from negative to positive in the 1990s, coherently with Atlantic multidecadal variability9,10,11. The western North Pacific warming resulted in intensification of trade winds to the west of the dateline. These trends have not contributed much to the global warming hiatus, but have greatly impacted rainfall over the western Pacific islands.
ER –

NR – 188
TY – JOUR
AU – Li, Xichen
AU – Xie, Shang-Ping
AU – Gille, Sarah T.
AU – Yoo, Changhyun
TI – Atlantic-induced pan-tropical climate change over the past three decades
JF – Nature Climate Change
PY – 2015
VL – 6
SP – 275
UR – http://dx.doi.org/10.1038/nclimate2840
DO – 10.1038/nclimate2840
AB – During the past three decades, tropical sea surface temperature (SST) has shown dipole-like trends, with warming over the tropical Atlantic and Indo-western Pacific but cooling over the eastern Pacific. Competing hypotheses relate this cooling, identified as a driver of the global warming hiatus1,2, to the warming trends in either the Atlantic3,4 or Indian Ocean5. However, the mechanisms, the relative importance and the interactions between these teleconnections remain unclear. Using a state-of-the-art climate model, we show that the Atlantic plays a key role in initiating the tropical-wide teleconnection, and the Atlantic-induced anomalies contribute ~55–75% of the tropical SST and circulation changes during the satellite era. The Atlantic warming drives easterly wind anomalies over the Indo-western Pacific as Kelvin waves and westerly anomalies over the eastern Pacific as Rossby waves. The wind changes induce an Indo-western Pacific warming through the wind–evaporation–SST effect6,7, and this warming intensifies the La Niña-type response in the tropical Pacific by enhancing the easterly trade winds and through the Bjerknes ocean dynamical processes8. The teleconnection develops into a tropical-wide SST dipole pattern. This mechanism, supported by observations and a hierarchy of climate models, reveals that the tropical ocean basins are more tightly connected than previously thought.
ER –

NR – 189
TY – JOUR
T1 – Climate Signals in the Mid- to High-Latitude North Atlantic from Altimeter Observations
AU – Li, Feili
AU – Jo, Young-Heon
AU – Yan, Xiao-Hai
AU – Liu, W. Timothy
PY – 2015
DO – 10.1175/JCLI-D-12-00670.1
JF – Journal of Climate
SP – 4905
EP – 4925
VL – 29
IS – 13
AB – The variability of the sea surface height anomaly (SSHA) in the mid- to high-latitude North Atlantic for the period of 1993?2010 was investigated using the ensemble empirical mode decomposition to identify the dominant time scales. Sea level variations in the North Atlantic subpolar gyre (SPG) are dominated by the annual cycle and the long-term increasing trend. In comparison, the SSHA along the Gulf Stream (GS) is dominated by variability at intraseasonal and annual time scales. Moreover, the sea level rise in the SPG developed at a reduced rate in the 2000s compared to rates in the 1990s, which was accompanied by a rebound in SSHA variability following a period of lower variability in the system. These changes in both apparent trend and low-frequency SSHA oscillations reveal the importance of low-frequency variability in the SPG. To identify the possible contributing factors for these changes, the heat content balance (equivalent variations in the sea level) in the subpolar region was examined. The results indicate that horizontal circulations may primarily contribute to the interannual to decadal variations, while the air?sea heat flux is not negligible at annual time scale. Furthermore, the low-frequency variability in the SPG relates to the propagation of Atlantic meridional overturning circulation (AMOC) variations from the deep-water formation region to midlatitudes in the North Atlantic, which might have the implications for recent global surface warming hiatus.
UR – https://doi.org/10.1175/JCLI-D-12-00670.1
ER –

NR – 190
TY – JOUR
TI – How Long will the Pause of Global Warming Stay Again?
AU – Bin, Huang Jian
AU – Yong, Luo
AU – Wu, Wang Shao
AU – Yu, Wen Xin
AU – Ci, Zhao Zong
PY – 2014
JO – Progressus Inquisitiones De Mutatione Climatis
VL – 10
IS – 6
SP – 465
EP – 468
DO – 10.3969/j.issn.1673-1719.2014.06.011
ER –

NR – 191
TY – JOUR
AU – Veettil, Bijeesh Kozhikkodan
AU – Pereira, Sebastián Felipe Ruiz
AU – Wang, Shanshan
AU – Valente, Pedro Teixeira
AU – Grondona, Atilio Efrain Bica
AU – Rondón, Adriana Coromoto Becerra Rondón
AU – Rekowsky, Isabel Cristiane
AU – de Souza, Sergio Florêncio
AU – Bianchini, Nilceia
AU – Bremer, Ulisses Franz
AU – Simões, Jefferson Cardia
TI – Un análisis comparativo del comportamiento diferencial de los glaciares en los Andes Tropicales usando teledetección
T2 – A comparative analysis of glacier retreat in the Tropical Andes using remote sensing
PY – 2016
JO – Investigaciones Geográficas
VL – 51
SP – 3
EP – 36
DO – 10.5354/0719-5370.2016.41215
UR – https://investigacionesgeograficas.uchile.cl/index.php/IG/article/view/41215
AB – In this research paper, we analysed the behaviour of Tropical Andean glaciers in a changing climate. We used multi-source satellite images as well as meteorological datasets to achieve this objective. Representative glaciers in four different climatic zones, namely the inner tropics, northern wet outer tropics, southern wet outer tropics and dry outer tropics, were considered in this study. Changes in annual maximum snowline during 1985 – 2015 and also the decadal changes in the area between 1975 and 2015 of these glaciers were calculated. Furthermore, we analysed the rate of glacier retreat during the occurrence of El Niño–Southern Oscillation and Pacific Decadal Oscillation. It is observed that the glaciers in both the inner and outer tropics underwent retreat during the study period and most of this retreat occurred during 1975 – 1997 which is parallel with the so-called Pacific shift. Exceptional variations in snowline altitude were observed when an El Niño event occurs during the warm phase of the Pacific Decadal Oscillation. No significant signals of the recent hiatus in global warming were observed, except in the dry outer tropics which are situated near the subtropical region.
ER –

NR – 192
TY – JOUR
TI – The Global Warming Hiatus Simulated in HadGEM2-AO Based on RCP8.5
AU – Wie, Jieun
AU – Moon, Byung-Kwon
AU – Kim, Ki-Young
AU – Lee, Johan
PY – 2014
JO – Journal of the Korean earth science society
VL – 35
IS – 4
SP – 249
EP – 258
DO – 10.5467/JKESS.2014.35.4.249
UR – http://www.koreascience.or.kr/article/ArticleFullRecord.jsp?cn=JGGHBA_2014_v35n4_249
AB – Despite the greenhouse gases like carbon dioxide have steadily increased in atmosphere, the overall trend of the global average surface air temperature has stalled during the last decade (2002-present). This phenomenon is often called hiatus or warming pause, which is challenging the prevailing view that anthropogenic forcing causes warming environment. Our study characterized the hiatus by analyzing the HadGEM2-AO (95 yrs) simulation data based on RCP8.5 scenario. The PC2 time series from the EOF of the zonal mean vertical ocean temperature has been defined as the index that represents the warming pause. The relationship between the hiatus, ENSO and the changes in climate system are identified by utilizing the newly defined PC2. Since the La Nina index (defined as the negative of NINO3 index) leads PC2 by about 11 months, it may be possible that the La Nina causes the warming to be interrupted. We also show that the cooling of the climate system closed tied to the heat penetration into the deep ocean, indicating the weakening the warming rate is due to the oceanic heat uptake. Finally, the global warming hiatus is characterized by the anomalous warming in Arctic region as well as the intensification of the trade wind in the equatorial Pacific.
ER –

NR – 193
TY – JOUR
TI – Linear and Nonlinear Trends of Extreme Temperatures in Korea
AU – Kim, Sang-Wook
AU – Song, Kanghyun
AU – Kim, Seo-Yeon
AU – Son, Seok-Woo
AU – Franzke, C.
JO – Atmosphere
VL – 24
IS – 3
SP – 379
EP – 390
PY – 2014
UR – http://www.dbpia.co.kr/Article/NODE02486406
AB – This study explores the long-term trends of surface air temperatures in 11 KMA stations over the period of 1960~2012. Both linear and nonlinear trends are examined for the 95th, 50th, and 5th percentiles of daily maximum (Tmax) and minimum temperatures (Tmin) by using quantile regression method. It is found that in most stations linear trends of Tmax and Tmin are generally stronger in winter than in summer, and warming trend of the 5th percentile temperature (cold extreme) is stronger than that of the 95th percentile temperature (warm extreme) in both seasons. The nonlinear trends, which are evaluated by the second order polynomial fitting, show a strong nonlinearity in winter. Specifically, winter temperatures have increased until 2000s but slightly decreased afterward in all percentiles. This contrasts with the 95th and 50th percentiles of summer Tmin that show a decreasing trend until 1980s then an increasing trend. While this result is consistent with a seasonal dependence of the recent global warming hiatus, most of the nonlinear trends are statistically insignificant, making a quantitative attribution of nonlinear temperature trends challenging.
ER –

NR – 194
TY – JOUR
TI – Enhanced Responses of Sea Surface Temperature over Offshore China to Global Warming and Hiatus
AU – Tan, Hongjian
AU – Cai, Rongshuo
AU – Huang, Ronghui
PY – 2016
JO – Advances in Climate Change Research
VL – 12
IS – 6
SP – 500
EP – 507
DO – 10.12006/j.issn.1673-1719.2016.038
UR – http://www.climatechange.cn/CN/abstract/abstract9266.shtml
AB – In this study, we assessed and compared the sea surface temperature (SST) trends between offshore China and other sea regions of interest as well as global mean surface temperature based on four SST datasets. The results revealed an enhanced SST response over offshore China during different periods. During the accelerated global warming periods (1980s and 1990s), SST over offshore China shows faster rising trend than the global mean. The most pronounced warming area is located over the East China Sea, with the rising rate up to 0.60? per decade, which is 5 times faster than that of the global mean. While during the hiatus period (1998-2014), SST over offshore China exhibits significant cooling trend. The decadal variability of offshore China SST is closely linked to the Pacific Decadal Oscillation (PDO). The periods with rapid warming (cooling) over offshore China are consistent with the positive (negative) phase of PDO. PDO may affect SST over offshore China through the East Asian Monsoon and Kuroshio Current.
ER –

NR – 195
TY – JOUR
TI – Research on the global warming Hiatus
AU – Lin, Xiaopei
AU – Xu, Lixiao
AU – Li, Jianping
AU – Luo, Dehai
AU – Liu, Hailong
PY – 2016
JO – Advances in Earth Science
VL – 31
IS – 10
SP – 995
EP – 1000
DO – 10.11867/j.issn.1001-8166.2016.10.0995
UR – http://www.adearth.ac.cn/article/2016/1001-8166-31-10-995.html
AB – A global warming “hiatus” has been observed since the beginning of the 21st century despite the increase in heat-trapping greenhouse gases, challenging the current global warming studies. Focusing on the phenomena and mechanisms of the global warming “hiatus”, the National Key Research Program of China launched a project in July, 2016. The main research themes of this project cover: ?Revealing the spatial and temporal variability of the global warming hiatus, and quantifying the contributions of external forcing and internal (natural) variability, respectively; ?Revealing the role of the atmosphere in the global heat and energy redistribution under global warming hiatus; ?Revealing the role of the ocean in the global heat and energy redistribution under global warming hiatus; ?Investigating the predictability of the global warming hiatus. The key scientific issues to be resolved include: ?Identifying characteristics of the global warming hiatus and discerning the roles of decadal, multi-decadal oscillations; ?Revealing the role of ocean-atmosphere dynamical processes in the global redistribution of heat and energy; ?Understanding the predictability of the global warming hiatus. The research aims to predict the future development of the global warming hiatus, and to point out the possible impacts on China and other important areas, including “The Belt and Road” core area and the Polar Regions.
ER –

NR – 196
TY – JOUR
TI – Research Progress on Hiatus in The Process of Global Warming
AU – Chen, Xingrong
AU – Cai Yi
AU – Tan Jing
AU – Wang Lei
PY – 2014
JO – Advances in Earth Science
VL – 29
IS – 8
SP – 947
EP – 955
UR – http://www.adearth.ac.cn/article/2014/1001-8166-29-8-0947.html
AB – In the 21st century, global warming hiatus has become a new hotspot in the research of climate change. This paper introduces the research progress on this phenomenon in detail, especially the validation studies of hiatus, research on the influence of the radiation forcing and the natural variability of the climate system due to air?sea interaction, and then puts forward several puzzles that still need to be solved on current research of hiatus. The paper particularly introduces the international major view, which think that the main reason of the hiatus in this century is that the strengthened trade wind on the background of the PDO negative phase leads to the warm water “accumulation”? in the equatorial western Pacific while the cooling in equatorial eastern Pacific causes the heat transferred down to the deep ocean. Therefore, hiatus phenomenon does not mean the stop of global warming, but just the heat transportation to the deep ocean, which is another manifestation of global warming.
ER –

NR – 197
TY – JOUR
TI – A review of recent studies on global warming hiatus
AU – Song, Bin
AU – Zhi, Xie-Fei
AU – Hu, Yao-Xing
PY – 2015
JO – Transactions of Atmospheric Sciences
VL – 38
IS – 2
SP – 145
EP – 154
DO – 10.13878/j.cnki.dqkxxb.20150105002
UR – http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=njqxxyxb201502001
AB – Since the industrial revolution, the content of anthropogenic greenhouse gas is increasing. As a result, the global surface air temperature grows rapidly. However, the global surface air temperature has stalled since 1998, despite the greenhouse gas steadily increases. This paper reviewed the latest research progress on this phenomenon, especially the mechanism of the global warming hiatus. There are two main viewpoints on the mechanism, namely, the external forcing and natural variability. The former includes the influence of solar activity, volcanic aerosol particles, man-made aerosol particles and stratospheric water vapor forcing. Scientists in the opinion of natural variability hold the idea that the missing heat produced by human activity has entered the deep ocean, especially the layer below 700 m. They believe that the oceans play a key role in the global warming hiatus. There are two main ideas for that: Pacific Decadal Oscillation (PDO), especially the cooling in the eastern tropical Pacific, and the Atlantic Meridional Overturning Circulation (AMOC). The widely accepted idea on the mechanism of recent global warming hiatus is natural variability. The missing heat has entered the deep ocean. But it still remains controversial which ocean basin gain the missing heat.
ER –

NR – 198
TY – JOUR
TI – Evolution of Surface Temperature during Global Warming Hiatus Based on Observations and CMIP5 Simulations
AU – He, Jinhai
AU – Zhan, Fengxing
AU – Qi, Li
AU – Wang, Di
PY – 2016
JO – Chinese Journal of Atmospheric Sciences
VL – 40
IS – 1
SP – 33
EP – 45
DO – 10.3878/j.issn.1006-9895.1409.14217
UR – http://www.dqkxqk.ac.cn/dqkx/dqkx/ch/html/20160105.htm
AB – The rise in global surface temperature has significantly declined after 2000. In this study, the evolution of the surface temperature of the global land-mean and Eurasia middle-high latitudes during the global warming hiatus was analyzed based on CRU observations. Simulations and projections were also evaluated using the Coupled Model Intercomparison Project 5 (CMIP5). The results indicate that, in the global warming hiatus period, the trend of the global land-mean surface temperature is only 0.14? (10 a)-1, which is half that during 1976-1999. The trend is less than that before 2000 in nine of the 13 global land regions, and four of them show a decreasing trend. The Eurasia middle-high latitude region is the most interesting among all the regions. For 1976-1999, the Eurasia middle-high latitude region shows the largest warming among all the land regions and reaches 0.50? (10 a)-1. After 2000, the trend significantly declines to -0.17? (10 a)-1, the greatest cooling trend over land, globally, contributing 49.13% of the remarkable change in global land surface temperatures before and after 2000. Furthermore, the surface temperature of the Eurasia middle-high latitude region shows an opposite change in autumn and winter after 2000; the temperature of the former rises by 0.86? (10 a)-1, while the that of the latter decreases by 2.68? (10 a)-1. In CMIP5, only the simulation and projects in BCC-CSM1.1 under the RCP2.6 scenario and MRI-ESM1 under the RCP8.5 scenario reproduce the evolution of the global land-mean and Eurasia middle-high latitude surface temperature, as well as the opposite change between autumn and winter of the Eurasia middle-high latitude region, during the global warming hiatus. The temperature projection of the BCC-CSM1.1 under the RCP2.6 scenario for the Eurasia middle-high latitude remains flat, near 1.2?, after 2012, and jumps to 2? after 2020. The change in the MRI-ESM1’s projected temperature under the RCP8.5 scenario is close to zero before 2030; the temperature then rises remarkably, to ? (10 a)-1.
ER –

NR – 199
TY – JOUR
TI – Hiatus of global warming: A review
AU – Su, Jingzhi
AU – Wen, Min
AU – Ding, Yihui
AU – Gao, Yongqi
AU – Song, Yafang
PY – 2016
JO – Chinese Journal of Atmospheric Sciences
VL – 40
IS – 6
SP – 1143
EP – 1153
DO – 10.3878/j.issn.1006-9895.1512.15242
UR – http://www.dqkxqk.ac.cn/dqkx/ch/reader/create_pdf.aspx?file_no=20160604&flag=1&journal_id=dqkx
ER –

NR – 200
TY – JOUR
TI – Debate on Global Warming “Hiatus”
AU – Zhao, Zongci
AU – Luo, Yong
AU – Huang, Jianbin
PY – 2016
JO – Climate Change Research
VL – 12
IS – 6
SP – 571
EP – 574
DO – 10.12006/j.issn.1673-1719.2016.055
UR – http://www.climatechange.cn/CN/10.12006/j.issn.1673-1719.2016.055
ER –

NR – 201
TY – JOUR
TI – Climate change science and sustainable development
AU – Qin, Dahe
PY – 2014
JO – Progress in Geography
VL – 33
IS – 7
SP – 874
EP – 883
DO – 10.11820/dlkxjz.2014.07.002
UR – http://www.progressingeography.com/CN/abstract/abstract14634.shtml
AB – Since the Fourth Assessment Report (AR4) was released by the Intergovernmental Panel on Climate Change (IPCC) in 2007, new observations have further proved that the warming of the global climate system is unequivocal. Each of the last three successive decades before 2012 has been successively warmer at global mean surface temperature than any preceding decade since 1850. 1983-2012 was likely the warmest 30-year period of the last 1400 years. From 1998 to 2012, the rate of warming of the global land surface slowed down, but it did not reflect the long-term trends in climate change. The ocean has warmed, and the upper 75 m of the ocean warmed by more than 0.11? per decade since 1970. Over the period of 1971 to 2010, 93% of the net energy increase in the Earth’s climate system was stored in the oceans. The rate of global mean sea level rise has accelerated, which was up to 3.2 mm yr-1 between 1993 and 2010. Anthropogenic global ocean carbon stocks were likely to have increased and caused acidification of the ocean surface water. Since 1971, the glaciers and the Greenland and Antarctic ice sheets have been losing mass. Since 1979, the Arctic sea ice extent deceased at 3.5% to 4.1% per decade, and the Antarctic sea ice extent in the same period increased by 1.2% to 1.8% per decade. The extent of the Northern Hemisphere snow cover has decreased. Since the early 1980s, the permafrost temperatures have increased in most regions. Human influence has been detected in the warming of the atmosphere and the ocean, changes in the water cycle, reductions in snow and ice, global mean sea level rise, and changes in climate extremes. The largest contribution to the increase in the anthropogenic radiative forcing was by the increase in the atmospheric concentration of CO2 since 1750. It led to more than half of global warming since the 1950s (with 95 % confidence). It is predicted using Coupled Model Intercomparison Project Phase 5 (CMIP5) and Representative Concentration Pathways (RCPs) that the global mean surface temperature will continue to rise for the end of this century, the frequency of extreme events such as heat waves and heavy precipitation will increase, and precipitation will present a trend of “the dry becomes drier, the wet becomes wetter”. The temperature of the upper ocean will increase by 0.6 to 2.0? compared to the period of 1986 to 2005, heat will penetrate from the surface to the deep ocean which will affect ocean circulation, and sea level will rise by 0.26 to 0.82 m in 2100. Cryosphere will continue to warm. To control global warming, humans need to reduce the greenhouse gas emissions. If the increase in temperature is higher than 2? than before industrialization, the mean annual economic losses worldwide will reach 0.2% to 2.0% of income, and cause large-scale irreversible effects, including death, disease, food insecurity, inland flooding and water logging, and rural drinking water and irrigation difficulties that affect human security. If taking prompt actions, however, it is still possible to limit the increase in temperature within 2?. To curb the gradually out-of-control global warming and achieve the goal of sustainable development of the human society, global efforts to reduce emissions are needed.
ER –

NR – 202
TY – JOUR
TI – Temperature mutation and globe warming stagnate study in typical area of Yellow River basin in recently 60years
AU – Huang, Xing
AU – Ma, Long
AU – Liu, Ting-xi
AU – Wang, Jing-ru
AU – Liu, Dan-hui
AU – Li, Hong-yu
PY – 2016
JO – China Environmental Science
VL – 36
IS – 11
SP – 3253
EP – 3262
UR – http://manu36.magtech.com.cn/Jweb_zghjkx/CN/abstract/abstract14853.shtml
AB – The part of Yellow River in Inner Mongolia was chosen as a typical area of Yellow River Basin. The regional annual average maximum temperature (AMaxT), annual average minimum temperature (AMinT) and annual average temperature (AvT) from 1951 to 2012 were selected and analyzed by Mann-Kendall method. The temperature variations before and after the mutation and the warming stagnate following the mutation were also discussed. Annual (or seasonal) AMinT mutation happened first on 1977 to 1987. Then the AvT and AMaxT mutation happened on 1978 to 1993 and 1978 to 1994, respectively. The mutation period of average autumn and winter temperature were same as AMaxT. The earliest intra-annual mutation was winter (1977 to 1978), and the latest was summer (1987 to 1994). The winter and AMaxT had more variations than summer and AMinT. The increase ratio or AMinT was 0.231~0.604?/10a which have the most contribution. All the annual (or seasonal) temperatures had a warming stagnate from 1997 to 2007 after the mutation, successively. The stagnate occurred in spring and not stagnate occurred in summer. Mostly annual and seasonal temperature stagnate happened later than the global period which winter firstly, then autumn, the AvT was the last one (on 2007). The AMaxT increase rate was lower in the period of after mutation and before stagnate. However, the decrease rate of AMaxT if faster after stagnate. The AMinT was on the contrary. This indicates that the AMinT was sensitive to temperature increase and the AMaxT was sensitive to the temperature decrease. In seasonal, the spring AMaxT increase rate is higher from mutation to stagnate, and the spring AMinT decrease rate was the fastest after the temperature stagnate which is -0.324?/a.
ER –

NR – 203
TY – JOUR
TI – Recent global-warming “hiatus” and its implications on the measures to be taken against global warming
AU – Junichi, Tsuitii
PY – 2014
JO – Energy and power
VL – 64
IS – 283
SP – 80
EP – 86
UR – http://ci.nii.ac.jp/naid/40020266117/
ER –

NR – 204
TY – JOUR
TI – Surface Temperature and Precipitation Variation of Pastoral Transitional Zone in Northern China during 1964-2013
AU – Zhao, Wei
AU – Wei, Zhigang
AU – Zheng, Zhiyuan
AU – Dong, Wenjie
PY – 2016
JO – Plateau Meteorology
VL – 35
IS – 4
SP – 979
EP – 988
DO – 10.7522/j.issn.1000-0534.2015.00079
UR – http://html.rhhz.net/gyqx/html/20160413.htm
AB – This study analyzed the spatial-temporal change of historical temperature and precipitation in pastoral transitional zone in Northern China, based on observational temperature and precipitation grid datasets during 1964-2013 from Chinese Meteorology Administration (CMA). The climate division was made using rotated empirical orthogonal function (REOF) in the meantime. The result shows that: (1) The whole pastoral transitional zone in Northern China can be divided into 4 regions which can be simply named the west region, the central region, the southern section of the east region, and the northern section of the east region, respectively. (2) In general, the pastoral transitional zone in Northern China had experienced a significant warming during 1964-2013 which was mainly attributed to the warming of winter and larger increase of minimum temperature rather than the increase of maximum temperature. The pastoral transitional zone in Northern China had also experienced a slightly decrease of precipitation (13 mm less during 1964 -2013), and it was largely because the summer precipitation had declined the most in this period. (3) Focused on sub-regions, the temperature of the central region in pastoral transitional zone increased the most in the period of 1964-2013 among 4 sub-regions. As for the precipitation, annual precipitation in western north region decreased in the last 50 years mostly because of the decrease of spring precipitation in local. Meanwhile, the annual precipitation in central region and the southern section of the east region had decreased as well, but differently, it can be mainly attributed to the summer precipitation’s decline. Moreover, the annual precipitation increased in the northern section of the east region, and the spring precipitation contributed it the most. (4) The pastoral transitional zone in Northern China has experienced a warming hiatus resembling to the global warming hiatus since late 1990s, only the temperature has declined more, meaning that the declining trend of temperature in pastoral transitional zone is more obvious.
ER –

NR – 205
TY – JOUR
TI – Characteristics of Climate Change over the Tibetan Plateau Under the Global Warming During 1979-2014
AU – Duan, Anmin
AU – Xiao, Zhixiang
AU – Wu, Guoxiong
PY – 2016
JO – Advances in Climate Change Research
VL – 12
IS – 5
SP – 374
EP – 381
DO – 10.12006/j.issn.1673-1719.2016.039
UR – http://www.climatechange.cn/CN/Y2016/V12/I5/374
AB – Global warming has been a hot issue during recent decades, while the global warming hiatus since 1998 was detected as documented by many papers, meanwhile the Tibetan Plateau (TP) experiencing a rapid warming process. Based on previous studies, this paper mainly reviews the TP climate change under the global warming in four aspects: temperature, snow cover, precipitation and atmospheric apparent heat source, and points out that the accelerated warming over the TP results in the retreat of snow cover accompanied by the increase of precipitation. Though the TP heat source has been declined in recent decades whether based on observation or reanalysis datasets, it shows large uncertainties.
ER –

NR – 206
TY – JOUR
TI – CMIP5 climate model simulates the empirical study of global temperature change from 1850 to 2014
AU – Meng, Wei
AU – Fangli, Qiao
PY – 2016
JO – SCIENTIA SINICA Terrae
VL – 46
IS – 12
SP – 1675
EP – 1688
DO – 10.1360/N072015-00465
UR – http://engine.scichina.com/publisher/scp/journal/SSTe/46/12/10.1360/N072015-00465
ER –

NR – 207
TY – JOUR
T1 – The Community Earth System Model (CESM) Large Ensemble Project: A Community Resource for Studying Climate Change in the Presence of Internal Climate Variability
AU – Kay, J. E.
AU – Deser, C.
AU – Phillips, A.
AU – Mai, A.
AU – Hannay, C.
AU – Strand, G.
AU – Arblaster, J. M.
AU – Bates, S. C.
AU – Danabasoglu, G.
AU – Edwards, J.
AU – Holland, M.
AU – Kushner, P.
AU – Lamarque, J.-F.
AU – Lawrence, D.
AU – Lindsay, K.
AU – Middleton, A.
AU – Munoz, E.
AU – Neale, R.
AU – Oleson, K.
AU – Polvani, L.
AU – Vertenstein, M.
PY – 2014
DO – 10.1175/BAMS-D-13-00255.1
JF – Bulletin of the American Meteorological Society
SP – 1333
EP – 1349
VL – 96
IS – 8
AB – While internal climate variability is known to affect climate projections, its influence is often underappreciated and confused with model error. Why? In general, modeling centers contribute a small number of realizations to international climate model assessments [e.g., phase 5 of the Coupled Model Intercomparison Project (CMIP5)]. As a result, model error and internal climate variability are difficult, and at times impossible, to disentangle. In response, the Community Earth System Model (CESM) community designed the CESM Large Ensemble (CESM-LE) with the explicit goal of enabling assessment of climate change in the presence of internal climate variability. All CESM-LE simulations use a single CMIP5 model (CESM with the Community Atmosphere Model, version 5). The core simulations replay the twenty to twenty-first century (1920?2100) 30 times under historical and representative concentration pathway 8.5 external forcing with small initial condition differences. Two companion 1000+-yr-long preindustrial control simulations (fully coupled, prognostic atmosphere and land only) allow assessment of internal climate variability in the absence of climate change. Comprehensive outputs, including many daily fields, are available as single-variable time series on the Earth System Grid for anyone to use. Early results demonstrate the substantial influence of internal climate variability on twentieth- to twenty-first-century climate trajectories. Global warming hiatus decades occur, similar to those recently observed. Internal climate variability alone can produce projection spread comparable to that in CMIP5. Scientists and stakeholders can use CESM-LE outputs to help interpret the observational record, to understand projection spread and to plan for a range of possible futures influenced by both internal climate variability and forced climate change.
UR – https://doi.org/10.1175/BAMS-D-13-00255.1
ER –

NR – 208
TY – JOUR
AU – Meehl, Gerald A.
AU – Teng, Haiyan
TI – Case studies for initialized decadal hindcasts and predictions for the Pacific region
JO – Geophysical Research Letters
VL – 39
IS – 22
UR – http://dx.doi.org/10.1029/2012GL053423
DO – 10.1029/2012GL053423
PY – 2012
AB – Case studies involving notable past decadal climate variability are analyzed for the mid-1970s climate shift, when the tropical Pacific warmed over a decade and globally averaged temperature rapidly increased, and the early 2000s hiatus when the tropical Pacific cooled over a decade and global temperatures warmed little. Ten year hindcasts following the CMIP5 decadal climate prediction experiment design are analyzed for those two periods using two different initialization techniques in a global coupled climate model, the CCSM4. There is additional skill in the initialized hindcasts for surface temperature patterns over the Pacific region for those two case studies over and above that in free-running historical simulations with the same model. A 30 year hindcast also shows added skill over the Pacific compared to the historical simulations. A 30 year prediction from the initialized model simulations shows less global warming for the 2016–2035 period than the free-running model projection for that same time period.
ER –

NR – 209
TY – JOUR
T1 – Anthropogenic CO2 warming challenged by 60-yearcycle
AU – Gervais, François
JO – Earth-Science Reviews
VL – 155
SP – 129
EP – 135
PY – 2016
DO – https://doi.org/10.1016/j.earscirev.2016.02.005
UR – http://www.sciencedirect.com/science/article/pii/S0012825216300277
AB – Time series of sea-level rise are fitted by a sinusoid of period ~60years, confirming the cycle reported for the global mean temperature of the earth. This cycle appears in phase with the Atlantic Multidecadal Oscillation (AMO). The last maximum of the sinusoid coincides with the temperature plateau observed since the end of the 20th century. The onset of declining phase of AMO, the recent excess of the global sea ice area anomaly and the negative slope of global mean temperature measured by satellite from 2002 to 2015, all these indicators sign for the onset of the declining phase of the 60-yearcycle. Once this cycle is subtracted from observations, the transient climate response is revised downwards consistent with latest observations, with latest evaluations based on atmospheric infrared absorption and with a general tendency of published climate sensitivity. The enhancement of the amplitude of the CO2 seasonal oscillations which is found up to 71% faster than the atmospheric CO2 increase, focus on earth greening and benefit for crops yields of the supplementary photosynthesis, further minimizing the consequences of the tiny anthropogenic contribution to warming.
ER –

NR – 210
TY – JOUR
AU – Lorentzen, Torbjørn
PY – 2015
TI – A statistical analysis of sea temperature data
JO – Theoretical and Applied Climatology
SP – 585
EP – 610
VL – 119
IS – 3
AB – The paper analyzes sea temperature series measured at two geographical locations along the coast of Norway. We address the question whether the series are stable over the sample period 1936–2012 and whether we can measure any signal of climate change in the regional data. We use nonstandard supF, OLS-based CUSUM, RE, and Chow tests in combination with the Bai-Perron’s structural break test to identify potential changes in the temperature. The augmented Dickey-Fuller, the KPSS, and the nonparametric Phillips-Perron tests are in addition applied in the evaluation of the stochastic properties of the series. The analysis indicates that both series undergo similar structural instabilities in the form of small shifts in the temperature level. The temperature at Lista (58° 06′ N, 06° 38′ E) shifts downward about 1962 while the Skrova series (68° 12′ N, 14° 10′ E) shifts to a lower level about 1977. Both series shift upward about 1987, and after a period of increasing temperature, both series start leveling off about the turn of the millennium. The series have no significant stochastic or deterministic trend. The analysis indicates that the mean temperature has moved upward in decadal, small steps since the 1980s. The result is in accordance with recent analyses of sea temperatures in the North Atlantic. The findings are also related to the so-called hiatus phenomenon where natural variation in climate can mask global warming processes. The paper contributes to the discussion of applying objective methods in measuring climate change.
UR – https://doi.org/10.1007/s00704-014-1119-x
DO – 10.1007/s00704-014-1119-x
ER –

NR – 211
TY – JOUR
AU – Li, Qingxiang
AU – Yang, Su
AU – Xu, Wenhui
AU – Wang, Xiaolan L.
AU – Jones, Phil
AU – Parker, David
AU – Zhou, Liming
AU – Feng, Yang
AU – Gao, Yun
TI – China experiencing the recent warming hiatus
JO – Geophysical Research Letters
VL – 42
IS – 3
UR – http://dx.doi.org/10.1002/2014GL062773
DO – 10.1002/2014GL062773
SP – 889
EP – 898
PY – 2015
AB – Based on the homogenized data set, we analyze changes in mean temperature and some extreme temperature indices over China since 1961 and especially during the recent warming hiatus period (1998–2012) in a global average context. The result shows that the decrease of annual mean maximum has contributed most to the decreases in overall mean temperature and in diurnal temperature range (DTR) during the warming hiatus period. In most parts of China except the southwest, the summer mean maximum temperature (TxS) shows the largest increase, while the winter mean minimum temperature (TnW) indicates slight cooling trends. These changes have augmented the seasonal cycle and increased the likelihood of extreme warm and cold events. Further analyses reveal that the increases in TxS are significantly correlated with concurrent increases in solar radiation. In southwest China, the annual mean temperature, TxS, TnW, and DTR increased during 1998–2012, possibly related to increased dryness in this region during the hiatus period.
ER –

NR – 212
TY – JOUR
AU – Ueda, Hiroaki
AU – Kamae, Youichi
AU – Hayasaki, Masamitsu
AU – Kitoh, Akio
AU – Watanabe, Shigeru
AU – Miki, Yurisa
AU – Kumai, Atsuki
TI – Combined effects of recent Pacific cooling and Indian Ocean warming on the Asian monsoon
JA – Nature Communications
PY – 2015
VL – 6
SP – 8854
UR – http://dx.doi.org/10.1038/ncomms9854
DO – 10.1038/ncomms9854
AB – Recent research indicates that the cooling trend in the tropical Pacific Ocean over the past 15 years underlies the contemporaneous hiatus in global mean temperature increase. During the hiatus, the tropical Pacific Ocean displays a La Niña-like cooling pattern while sea surface temperature (SST) in the Indian Ocean has continued to increase. This SST pattern differs from the well-known La Niña-induced basin-wide cooling across the Indian Ocean on the interannual timescale. Here, based on model experiments, we show that the SST pattern during the hiatus explains pronounced regional anomalies of rainfall in the Asian monsoon region and thermodynamic effects due to specific humidity change are secondary. Specifically, Indo-Pacific SST anomalies cause convection to intensify over the tropical western Pacific, which in turn suppresses rainfall in mid-latitude East Asia through atmospheric teleconnection. Overall, the tropical Pacific SST effect opposes and is greater than the Indian Ocean SST effect.
ER –

NR – 213
TY – JOUR
AU – Saffioti, Claudio
AU – Fischer, Erich M.
AU – Knutti, Reto
TI – Contributions of atmospheric circulation variability and data coverage bias to the warming hiatus
JO – Geophysical Research Letters
VL – 42
IS – 7
UR – http://dx.doi.org/10.1002/2015GL063091
DO – 10.1002/2015GL063091
SP – 2385
EP – 2391
PY – 2015
AB – The warming hiatus shows a strong seasonal and geographical asymmetry, with cooling in the Northern Hemisphere winter, especially over land, and warming elsewhere and in the other seasons. We show that the characteristics of the Northern Hemisphere winter cooling in 1998–2012 can mostly be explained by missing observations and by internal variability in the atmospheric circulation of the Northern Hemisphere extratropics. Estimates of the annual and seasonal temperature trends in 1998–2012 obtained by considering the concurrent effects of unforced natural variability and of coverage bias are much closer to the corresponding long-term trends. Reanalyses suggest that the coverage bias was exceptionally pronounced during recent years and that an area of strong warming was missed due to the incomplete observational coverage. Coupled Model Intercomparison Project Phase 5 climate models indicate that trends in atmospheric circulation during the hiatus period did not occur as a response to anthropogenic forcing.
ER –

NR – 214
TY – JOUR
T1 – Clarifying the Roles of Greenhouse Gases and ENSO in Recent Global Warming through Their Prediction Performance
AU – Triacca, Umberto
AU – Pasini, Antonello
AU – Attanasio, Alessandro
AU – Giovannelli, Alessandro
AU – Lippi, Marco
PY – 2014
DO – 10.1175/JCLI-D-13-00784.1
JF – Journal of Climate
SP – 7903
EP – 7910
VL – 27
IS – 20
AB – It is well known that natural external forcings and decadal-to-millennial variability drove changes in the climate system throughout the Holocene. Regarding recent times, attribution studies have shown that greenhouse gases (GHGs) determined the trend of temperature (T) in the last half century, while circulation patterns contributed to modify its interannual, decadal, or multidecadal behavior over this period. Here temperature predictions based on vector autoregressive models (VARs) have been used to study the influence of GHGs and El Niño?Southern Oscillation (ENSO) on recent temperature behavior. It is found that in the last decades of steep temperature increase, ENSO shows just a very short-range influence on T, while GHGs are dominant for each forecast horizon. Conversely and quite surprisingly, in the previous quasi-stationary period the influences of GHGs and ENSO are comparable, even at longer range. Therefore, if the recent hiatus in global temperatures should persist into the near future, an enhancement of the role of ENSO can be expected. Finally, the predictive ability of GHGs is more evident in the Southern Hemisphere, where the temperature series is smoother.
UR – https://doi.org/10.1175/JCLI-D-13-00784.1
ER –

NR – 215
TY – JOUR
T1 – The global warming hiatus’s irrelevance
JO – Science
SP – 1482
LP – 1483
DO – 10.1126/science.350.6267.1482-d
VL – 350
IS – 6267
AU – Wehner, Michael F.
AU – Easterling, David R.
PY – 2015
UR – http://science.sciencemag.org/content/350/6267/1482.4.abstract
ER –

NR – 216
TY – JOUR
AU – Quirk, Tom
PY – 2012
TI – Did the global temperature trend change at the end of the 1990s?
JO – Asia-Pacific Journal of Atmospheric Sciences
SP – 339
EP – 344
VL – 48
IS – 4
AB – The apparent leveling of the global temperature time series at the end of the 1990s may represent a break in the upward trend. A study of the time series measurements for temperature, carbon dioxide, humidity and methane shows changes coincident with phase changes of the Atlantic and Pacific Decadal Oscillations. There are changes in carbon dioxide, humidity and methane measurement series in 2000. If these changes mark a phase change of the Pacific Decadal Oscillation then it might explain the global temperature behavior.
UR – https://doi.org/10.1007/s13143-012-0032-4
DO – 10.1007/s13143-012-0032-4
ER –

NR – 217
TY – JOUR
TI – Discussion of the case of the missing heat
AU – Parker, Albert
PY – 2014
JO – Nonlinear Engineering
VL – 3
IS – 4
SP – 247
EP – 253
DO – 10.1515/nleng-2014-0011
UR – http://www.degruyter.com/view/j/nleng.ahead-of-print/nleng-2014-0011/nleng-2014-0011.xml
AB – The sea level projection of a 1 meter rise for the 21st century depends on climate models that have projected a given amount of anthropogenic warming during the same period. However, these same climate models predicted a warming also from 2000 to 2014, which has not been seen in the global surface temperature. Researchers have proposed several solutions such as the fact that the “missing heat” was accumulated in the deep ocean. However, no evidences of a sufficient warming of the deep oceans have been observed. Other arguments has been proposed as well and found unsatisfactory. There is the opportunity that the “heat” is not “real” but “missing” or “hiding” somewhere. If the climate model projected “heat” that simply does not exist in reality in the first place, consequently the models overestimate the anthropogenicwarming and also the sea level projections for the 21st century are overestimated.
ER –

NR – 218
TY – JOUR
T1 – Expected halt in the current global warming trend?
AU – Njau, Ernest C.
JO – Renewable Energy
VL – 30
IS – 5
SP – 743
EP – 752
PY – 2005
DO – https://doi.org/10.1016/j.renene.2004.07.011
UR – http://www.sciencedirect.com/science/article/pii/S0960148104002939
AB – The variation patterns of global temperature were considerably turbulent from about 1870 up to 1940. Then just after 1940 these patterns underwent a sunspot-related change and adopted to relatively less turbulent variability. It is established here that these global temperature patterns are currently in the process of undergoing a sunspot-related change from the post-1940 relatively less turbulent variability back into relatively more turbulent variability. This apparently imminent state of more turbulent variability is expected to stop and at least slightly reverse the global warming trend, which has been going on since about 1965. Besides, it is shown separately that the mean of ‘global mean temperature variations’ reaches the next peak at about the year 2005 after which it will expectedly be on a decreasing trend. Finally, it is shown that, contrary to projections made in the Third IPCC Assessment Report, Greenland is currently in an ongoing cooling trend which is expected to last up to at least the year 2035.
ER –

NR – 219
TY – JOUR
TI – Why global warming went missing since the year 2000
AU – Parker, Albert
PY – 2013
JO – Nonlinear Engineering
VL – 2
IS – 3-4
SP – 129
EP – 135
DO – 10.1515/nleng-2013-0017
UR – http://www.degruyter.com/view/j/nleng.2013.2.issue-3-4/nleng-2013-0017/nleng-2013-0017.xml
AB – Over the period January 2004 to present, the seas have experienced the lack of any warming, as finally properly measured in the ARGO project where a global array of more than 3,600 free-drifting profiling floats has measured the temperature of the upper 2000 m of the sea as it was not possible before. The warming of the seas has been a negligible 1.1*10-3 °C/year on average over the layer 0 – 2000 dbar below the accuracy of the measure. Over the period January 2000 to present, the measured land and sea temperatures of the less reliable GISS, NCDC and HADCRUT4 data sets have shown a small warming of 4.2*10-3 °C/year on average. Same period, the climate models propose for the land and sea temperatures an unrealistic warming of 20.5*10-3 °C/year (average of CMIP3) and 18.2*10-3 °C/year (average of the CMIP5). The “inconvenient truth” is that climate models are predicting a warming when there is no warming rather than simply overestimating the warming as discussed so far. The paper presents the failed validation of the climate models since their introduction and suggests the reasons of their failure in the overrated effect of the changed composition of the atmosphere and the neglected natural oscillations.
ER –

NR – 220
TY – JOUR
TI – Key Issues on Debating about the Global Warming
AU – Wang, Shaowu
AU – Ge, Quansheng
AU – Wang, Fang
AU – Wen, Xinyu
AU – Huang, Jianbin
PY – 2010
JO – Advances in Earth Science
VL – 6
UR – http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXJZ201006015.htm
AB – Key issues on debating about global warming are reviewed:?Does the global warming pause? The answer is not sure.The HadCRUT3 data show that the temperature during 1999-2008 increased only a little(0.07?/10a),but this decade is still the most warmest one among the last 30 years.However,the data from NASA GISS indicate that the temperature increased in the same period is higher(0.19?/10a).Thus,global surface temperature in recent years oscillates on a warm level.However,natural variability needs to be taken into consideration.?Does the global warming be caused fully by anthropogenic factors? The answer is no.ENSO,solar activity,volcanism,and thermohaline circulation can also exert impact in some extent on climate change,though the morden global warming may be mostly attributed to the increasing of greenhouse effect.However,the natural factors may sometimes overwhelm the anthropogenic effect in the interannual to interdecadal time scale.Specially,the solar activity factor should be given more attention.?Does the impact of global warming become more evident recently? The answer is yes.New observational datas indicate that the melting speed of glaciers and ice caps and rising speed of sea level in recent years have exceeded the related projections by IPCC 4th Assessment Report.Accordingly,the updated projection of the future sea level also increases.
ER –

NR – 221
TY – JOUR
TI – Mechanisms for the hiatus in global warming
AU – Tung, Ka-Kit
AU – Zhang, Rong
AU – Trenberth, Kevin E.
PY – 2014
JO – Engineering Sciences
VL – 2
DO – 10.3969/j.issn.1672-4178.2014.02.007
UR – http://d.wanfangdata.com.cn/periodical_zggckx-e201402007.aspx
AB – The observed global mean temperature is the highest on record for the past decade but has plateaued to form an apparent“hiatus”in global temperature rise,with an almost zero short-term trend. Several speakers presented results on the hiatus and suggested possible mechanisms.
ER –

NR – 222
TY – JOUR
TI – On the definition and identifiability of the alleged “hiatus” in global warming
AU – Lewandowsky, Stephan
AU – Risbey, James S.
AU – Oreskes, Naomi
JF – Scientific Reports
PY – 2015
VL – 5
SP – 16784
UR – http://dx.doi.org/10.1038/srep16784
DO – 10.1038/srep16784
AB – Recent public debate and the scientific literature have frequently cited a “pause” or “hiatus” in global warming. Yet, multiple sources of evidence show that climate change continues unabated, raising questions about the status of the “hiatus”. To examine whether the notion of a “hiatus” is justified by the available data, we first document that there are multiple definitions of the “hiatus” in the literature, with its presumed onset spanning a decade. For each of these definitions we compare the associated temperature trend against trends of equivalent length in the entire record of modern global warming. The analysis shows that the “hiatus” trends are encompassed within the overall distribution of observed trends. We next assess the magnitude and significance of all possible trends up to 25 years duration looking backwards from each year over the past 30 years. At every year during the past 30 years, the immediately preceding warming trend was always significant when 17 years (or more) were included in the calculation, alleged “hiatus” periods notwithstanding. If current definitions of the “pause” used in the literature are applied to the historical record, then the climate system “paused” for more than 1/3 of the period during which temperatures rose 0.6?K.
ER –

NR – 223
TY – JOUR
AU – Lempereur, Morine
AU – Limousin, Jean-Marc
AU – Guibal, Frédéric
AU – Ourcival, Jean-Marc
AU – Rambal, Serge
AU – Ruffault, Julien
AU – Mouillot, Florent
TI – Recent climate hiatus revealed dual control by temperature and drought on the stem growth of Mediterranean Quercus ilex
JO – Global Change Biology
JA – Glob Change Biol
VL – 23
IS – 1
UR – http://dx.doi.org/10.1111/gcb.13495
DO – 10.1111/gcb.13495
SP – 42
EP – 55
PY – 2017
AB – A better understanding of stem growth phenology and its climate drivers would improve projections of the impact of climate change on forest productivity. Under a Mediterranean climate, tree growth is primarily limited by soil water availability during summer, but cold temperatures in winter also prevent tree growth in evergreen forests. In the widespread Mediterranean evergreen tree species Quercus ilex, the duration of stem growth has been shown to predict annual stem increment, and to be limited by winter temperatures on the one hand, and by the summer drought onset on the other hand. We tested how these climatic controls of Q. ilex growth varied with recent climate change by correlating a 40-year tree ring record and a 30-year annual diameter inventory against winter temperature, spring precipitation, and simulated growth duration. Our results showed that growth duration was the best predictor of annual tree growth. We predicted that recent climate changes have resulted in earlier growth onset (-10 days) due to winter warming and earlier growth cessation (-26 days) due to earlier drought onset. These climatic trends partly offset one another, as we observed no significant trend of change in tree growth between 1968 and 2008. A moving-window correlation analysis revealed that in the past, Q. ilex growth was only correlated with water availability, but that since the 2000s, growth suddenly became correlated with winter temperature in addition to spring drought. This change in the climate–growth correlations matches the start of the recent atmospheric warming pause also known as the ‘climate hiatus’. The duration of growth of Q. ilex is thus shortened because winter warming has stopped compensating for increasing drought in the last decade. Decoupled trends in precipitation and temperature, a neglected aspect of climate change, might reduce forest productivity through phenological constraints and have more consequences than climate warming alone.
ER –

NR – 224
TY – JOUR
T1 – Briefing: How do we know the globe has warmed? What do we know about why?
AU – Thorne, Peter
PY – 2015
JF – Proceedings of the Institution of Civil Engineers – Forensic Engineering
VL – 168
IS – 2
SP – 58
EP – 64
DO – 10.1680/feng.15.00003
UR – https://www.icevirtuallibrary.com/doi/abs/10.1680/feng.15.00003
AB – This briefing outlines the evidence from instrumental records that leads to an unequivocal finding that the world has warmed. It then goes on to address the underlying causes, showing that only through invoking the effects of humans can the last 50 years be adequately explained. Finally, it addresses the recent hiatus/pause in warming of global surface temperatures and the implications thereof.
UR – https://doi.org/10.1680/feng.15.00003
ER –

NR – 225
TY – JOUR
TI – Characteristics of the Trends in the Global Tropopause Estimated From COSMIC Radio Occultation Data
AU – P. Gao
AU – X. Xu
AU – X. Zhang
PY – 2015
JO – IEEE Transactions on Geoscience and Remote Sensing
VL – 53
IS – 12
SP – 6813
EP – 6822
DO – 10.1109/TGRS.2015.2449338
UR – https://ieeexplore.ieee.org/abstract/document/7156128/
AB – This paper discusses the variabilities and trends in the global tropopause based on the gridded monthly mean Global Positioning System radio occultation data from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission during July 2006-February 2014. We find that the tropopause height can reflect El Niño-Southern Oscillation (ENSO) events. The correlation coefficient between global tropopause height anomalies and the Niño 3.4 sea surface temperature index is 0.53, with a maximum correlation coefficient of 0.8 at a lag of three months. We present first the detailed investigations about the spatial distribution of trends in tropopause parameters in each 10° × 5° longitude-latitude grid cell over the globe and find that the rates of change in the tropopause parameters during this time period are high in some particular regions such as the Southern Indian Ocean, Antarctica, Western Europe, North Pacific, and the east coast of North America. An analysis of global monthly means of the tropopause parameters indicates a global tropopause height increase of 0.03 ± 2.36 m/year during 2006-2014, with a corresponding temperature increase of 0.020 ± 0.008°C/year, and a pressure increase of 0.11 ± 0.059 hPa/year. The upward trend of tropopause height is significantly weaker than that in the past years, which might be attributed to the expected stratospheric ozone recovery associated with the Montreal Protocol, the global warming slowdown, and the abnormal global climate change in recent years. The trends of the tropopause parameters are the most significant over the Southern Indian Ocean and Antarctica during September/October/November, which could be due to the stratospheric ozone recovery.
ER –

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