AGW Observer

Observations of anthropogenic global warming

New research – temperature (September 5, 2016)

Posted by Ari Jokimäki on September 5, 2016

Some of the latest papers on temperature (in a climatic sense) are shown below. First a few highlighted papers with abstracts and then a list of some other papers. If this subject interests you, be sure to check also the other papers – they are by no means less interesting than the highlighted ones.


Observed and simulated full-depth ocean heat-content changes for 1970–2005 (Cheng et al. 2016)

Abstract: Greenhouse-gas emissions have created a planetary energy imbalance that is primarily manifested by increasing ocean heat content (OHC). Updated observational estimates of full-depth OHC change since 1970 are presented that account for recent advancements in reducing observation errors and biases. The full-depth OHC has increased by 0.74 [0.68, 0.80]  ×  1022 J yr-1 (0.46 Wm−2) and 1.22 [1.16–1.29]  ×  1022 J yr-1 (0.75 Wm-2) for 1970–2005 and 1992–2005, respectively, with a 5 to 95 % confidence interval of the median. The CMIP5 models show large spread in OHC changes, suggesting that some models are not state-of-the-art and require further improvements. However, the ensemble median has excellent agreement with our observational estimate: 0.68 [0.54–0.82]  ×  1022 J yr-1 (0.42 Wm-2) from 1970 to 2005 and 1.25 [1.10–1.41]  ×  1022 J yr-1 (0.77 Wm-2) from 1992 to 2005. These results increase confidence in both the observational and model estimates to quantify and study changes in Earth’s energy imbalance over the historical period. We suggest that OHC be a fundamental metric for climate model validation and evaluation, especially for forced changes (decadal timescales).

Pacific sea level rise patterns and global surface temperature variability (Peyser et al. 2016)

Abstract: 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.

Contrasting effects of urbanization and agriculture on surface temperature in eastern China (Zhou et al. 2016)

Abstract: The combined effect of urbanization and agriculture, two most pervasive land use activities, on the surface climate remains poorly understood. Using Moderate Resolution Imaging Spectroradiometer data over 2010–2015 and forests as reference, we showed that urbanization warmed the land surface temperature (LST), especially during the daytime and in growing seasons (maximized at 5.0 ± 2.0°C in May), whereas agriculture (dominated by double-cropping system) cooled the LST in two growing seasons during the daytime and all the months but July during the nighttime in Jiangsu Province, eastern China. Collectively, they had insignificant effects on the LST during the day (−0.01°C) and cooled the LST by −0.6°C at night. We also found large geographic variations associated with their thermal effects, indicated by a warming tendency southward. These spatiotemporal patterns depend strongly on vegetation activity, evapotranspiration, surface albedo, and the background climate. Our results emphasize the great potential of agriculture in offsetting the heating effects caused by rapid urbanization in China.

A summer temperature bias in early alcohol thermometers (Camuffo & Valle, 2016)

Abstract: This paper analyses the response of alcohol thermometers in relation to the departure from linearity and the choice of the calibration points. The result is that alcohol thermometers are affected by large departures that reach a maximum (i.e. −6 °C) at 50 °C ambient temperature. This may have caused a severe bias in early records, when alcohol thermometers were popular, especially during the Little Ice Age. Choosing a lower temperature for the upper point, calibration may substantially reduce this bias. Examples are given with thermometers in use in the 17th and 18th centuries. A careful correction of long series is necessary to avoid misleading climate interpretations.

The phenology of Arctic Ocean Surface warming (Steele & Dickinson, 2016)

Abstract: In this work, we explore the seasonal relationships (i.e., the phenology) between sea ice retreat, sea surface temperature (SST), and atmospheric heat fluxes in the Pacific Sector of the Arctic Ocean, using satellite and reanalysis data. We find that where ice retreats early in most years, maximum summertime SSTs are usually warmer, relative to areas with later retreat. For any particular year, we find that anomalously early ice retreat generally leads to anomalously warm SSTs. However, this relationship is weak in the Chukchi Sea, where ocean advection plays a large role. It is also weak where retreat in a particular year happens earlier than usual, but still relatively late in the season, primarily because atmospheric heat fluxes are weak at that time. This result helps to explain the very different ocean warming responses found in two recent years with extreme ice retreat, 2007 and 2012. We also find that the timing of ice retreat impacts the date of maximum SST, owing to a change in the ocean surface buoyancy and momentum forcing that occurs in early August that we term the Late Summer Transition (LST). After the LST, enhanced mixing of the upper ocean leads to cooling of the ocean surface even while atmospheric heat fluxes are still weakly downward. Our results indicate that in the near-term, earlier ice retreat is likely to cause enhanced ocean surface warming in much of the Arctic Ocean, although not where ice retreat still occurs late in the season.

Other papers

Comparisons of time series of annual mean surface air temperature for China since the 1900s: Observations, model simulations and extended reanalysis (Li et al. 2016)

First ground-based observations of mesopause temperatures above the Eastern-Mediterranean Part I: Multi-day oscillations and tides (Silber et al. 2016)

An enhanced single-channel algorithm for retrieving land surface temperature from Landsat series data (Wang et al. 2016)

Observed changes of temperature extremes in Serbia over the period 1961 − 2010 (Ruml et al. 2016)

The inter-annual variations and the long-term trends of monthly air temperatures in Iraq over the period 1941–2013 (Muslih & Błażejczyk, 2016)

A multiregion model evaluation and attribution study of historical changes in the area affected by temperature and precipitation extremes (Dittus et al. 2016)

Changes in wind speed under heat waves enhance urban heat islands in Beijing metropolitan area (Li et al. 2016)

Regional differential behaviour of maximum temperatures in the Iberian Peninsula regarding the Summer NAO in the second half of the twentieth century (Favà et al. 2016)

Confidence intervals for time averages in the presence of long range correlations, a case study on earth surface temperature anomalies (Massah & Kantz, 2016)

An ensemble of ocean reanalyses for 1815–2013 with sparse observational input (Giese et al. 2016)

Arctic-North Pacific coupled impacts on the late autumn cold in North America (Sung et al. 2016)

Wet-bulb, dew point, and air temperature trends in Spain (Moratiel et al. 2016)

Insights into elevation-dependent warming in the Tibetan Plateau-Himalayas from CMIP5 model simulations (Palazzi et al. 2016)

Spatial variations in temperature in a mountainous region of Jeju Island, South Korea (Um & Kim, 2016)

Gap filling and homogenization of climatological datasets in the headwater region of the Upper Blue Nile Basin, Ethiopia (Woldesenbet et al. 2016)

A homogenized long-term temperature record for the Western Cape Province in South Africa: 1916–2013 (Lakhraj-Govender et al. 2016)

Inter-model diversity of Arctic amplification caused by global warming and its relationship with the Inter-tropical Convergence Zone in CMIP5 climate models (Yim et al. 2016)

Urban–rural differences in near-surface air temperature as resolved by the Central Europe Refined analysis (CER): sensitivity to planetary boundary layer schemes and urban canopy models (Jänicke et al. 2016)

Monotonic Decrease of the Zonal SST Gradient of the Equatorial Pacific as a Function of CO2 Concentration in CCSM3 and CCSM4 (Yang et al. 2016)

Recent seasonal and long-term changes in southern Australian frost occurrence (Crimp et al. 2016)

Surface temperature trends from homogenized time series in South Africa: 1931–2015 (Kruger & Nxumalo, 2016)

Investigations of the middle atmospheric thermal structure and oscillations over sub-tropical regions in the Northern and Southern Hemispheres (Sharma et al. 2016)

Recent amplification of the North American winter temperature dipole (Singh et al. 2016)

Use of remotely-sensed land surface temperature as a proxy for air temperatures at high elevations: Findings from a 5000 metre elevational transect across Kilimanjaro (Pepin et al. 2016)

Spatial distribution of temperature trends and extremes over Maharashtra and Karnataka States of India (Dhorde et al. 2016)

Assessing atmospheric temperature data sets for climate studies (Cederlöf et al. 2016)

Ocean heat uptake and interbasin transport of passive and redistributive surface heating (Garuba & Klinger, 2016)

Temperature and precipitation regional climate series over the central Pyrenees during 1910–2013 (Pérez-Zanón et al. 2016)

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