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Observations of anthropogenic global warming

Flaws of Lüdecke & Weiss

Posted by Ari Jokimäki on January 11, 2018

Once again a paper that looks at solar-climate connection turns out to be deeply flawed. It contains bad methodology, bad result handling, bad conclusions, and a biased reference list.

Data handling process of Lüdecke & Weiss (2018).

A few months ago, a new paper was published by Lüdecke and Weiss (LW17). Both Lüdecke and Weiss are known climate change contrarians. Serious problems have been reported from their previous work, which used some of the same methods that were used in this new one. The new paper has been published by Bentham Open, which has somewhat questionable reputation.

Climate change contrarians are liking this of course and recently I also encountered the paper when it was shown to me as a proof for something. I decided to take a more thorough look at the paper.

The reference list

The first thing that jumps out from LW17 is the papers they cite in their introduction section. You can immediately see that their review of existing research is biased. They cite Scafetta but not his critics. They cite Svensmark but not his critics. They cite Friis-Christensen & Lassen but not their critics (even F-C & L themselves have later agreed that the findings they reported in the paper cited by LW17 were not correct). They cite lots of papers that suggest some kind of influence of the sun on Earth’s climate, but they leave the multitude of papers that state clearly that sun hasn’t caused current climate change almost un-cited.

The reference list of LW17 is quite long which suggests that they have been relatively thorough in trying to find lot of references that support their argumentation. It also hints to the possibility that the biased reference list is by design and not just an accident due to sloppy paper search.

The methods of the study

The methods section (sections “The Data” and “Spectral Analysis”) of LW17 contains some curious issues. Perhaps the worst aspect of the methods section is that they haven’t described all the methods they used. Their later sections contain many steps that haven’t been described with enough detail in the paper, such as making a representation of the temperature reconstruction from the three sine waves and the steps involved in solar variability – temperature comparison.

Moving on to the things they describe in the methods section, here’s a quote describing one step in the LW17 data processing:

For Bün, HADCRUT4 and Pet respectively the most recent years which show unusual deviations from the remaining reconstructions were also omitted.

This is a kind of thing I have seen climate change contrarians using in their fraud accusations. Yet, I have seen climate change contrarians claiming to have read this paper thoroughly and accepting it as truth without a question, and even defending it fiercely.

Another thing is how LW17 have adjusted the satellite data to HadCRUT4 data. They took 1979 values for each and then shifted satellite data so that their 1979 values were the same (I’m not 100% sure that they did it exactly like this – they don’t give the details – but I think that the process I described results in what they did). I think using only one year worth of data to align the two records is a bad idea. It’s especially bad because there was an El Niño in 1979-1980. El Niño generally shows up more in satellite records than in surface temperature records so using an El Niño year as a baseline creates a bias between the two records (the satellite record runs a bit low after this). I would have used several years of data to align the two records, 10 years for example. They also seem to use only one year data to align their source reconstructions together.

LW17 have used temperature reconstructions from all over the world. This is good. They have also adjusted each reconstruction to a common baseline. This is also good. Their method to create a global data set out of them is a bad one, though. They have computed a simple mean of the reconstructions for each year. There is no area averaging or anything but just a simple mean. To illustrate why this is bad, they have only three reconstructions from the Southern Hemisphere (SH) while they have dozens of reconstructions from the Northern Hemisphere (NH) (making their reconstruction practically a NH one instead a global one). This means that the three reconstructions from SH are strongly out-weighted by the NH reconstructions. In a global temperature reconstruction both hemispheres should have an equal weight but in LW17 they don’t have that, not even close.

Making the SH-NH imbalance even worse in LW17, two of the three reconstructions from SH only cover time-period from 1640 to 1987 and from 1640 to 1993 while they describe their reconstruction as “a global temperature mean G7 over the last 2000 years”. Furthermore, the only SH reconstruction covering the full 2000 years is an ice core based temperature reconstruction from Antarctica which has temporal resolution of 17 to 50 years while the NH records have annual resolution. Hence, most of the LW17 temperature reconstruction is lots of NH records + one bad resolution SH record.

In addition, all the proxies are from land areas but LW17 use global instrumental and satellite data which includes also ocean surface area. Yet another thing is that the NH reconstructions in LW17 seem to be somewhat clustered around North Atlantic, which is a region known to show the Medieval Warm Period very clearly. Overall, the LW17 temperature reconstruction is a strange mix of reconstructions patched together with very questionable methods, and it really is just a NH reconstruction with an emphasis on North Atlantic region.

For the solar activity, LW17 use only one reconstruction that has been constructed from different sources. They seem to use the reconstruction as it is without tampering with it, which seems to be a good thing in the light of what was seen above.

The results of the study

In their analysis, LW17 concentrate on cycles only and mainly to past climate, so the study has only little relevance to current climate change. Causes of past climate changes do not mean that greenhouse gases couldn’t cause climate change now, and the presence of cycles in Earth’s climate don’t negate the effects of greenhouse gases, but climatic cycles and greenhouse gas forcing can (and do) co-exist.

LW17 don’t offer much new to sun-climate connection knowledge either because their main result is a possible correlation between the two which doesn’t offer any information other than solar variability might have an effect on Earth’s climate, which we knew already anyway.

But in addition to general insignificance of the study and the problems identified in the previous sections, there are further problems in the results section of the paper.

LW17 perform a Fourier transformation to their temperature reconstruction and then they select three strongest peaks from the Fourier transformation result. However, from their Figure 2 can be seen that one of the selected peaks (the 1000-year peak) is not statistically significant (it doesn’t exceed what they call “false alarm line”) while some of the statistically significant peaks (~65 year and ~50 year peaks) were not selected. LW17 do not discuss the issue. They just state that they have selected the three strongest peaks.

Next, LW17 use the three selected peaks to do an inverse Fourier transform. The result of this is a representation of their original temperature reconstruction. This hasn’t been described in the methods section, and they don’t also describe it in the results section adequately. They only mention that they have done an inverse Fourier transformation.

They compute a correlation between the original temperature reconstruction and the sine wave representation. Resulting correlation is quite good, but it doesn’t mean much because they correlate an original series with a series that has been constructed from the original series. In practice, they just compute a correlation between two representations of a same signal. This would be okay if they would have just used the correlation to check that the temperature reconstruction from the three sine waves is a reasonably good representation of the original reconstruction, and then proceed with the actual analysis, but they seem to treat the correlation value as one of their most important results, and there’s no further analysis with the inverse Fourier representation.

LW17 continue their analysis under the section “Sun’s Activity and Climate”. For many readers, it probably will not be a surprise that this section also contains problems.

In this section, LW17 first discuss the Fourier transformation results of solar activity proxy series they are using. Their discussion is a stub one. Based on the peaks found, they mention that the three peaks selected from the temperature reconstruction can also be seen in solar activity series. Below is an excerpt of their Figure 2.

The Table 2 (T2) of LW17 claims to show “Strongest spectral peaks for the records Chr, Bün, McK, Vill-N, Vill-S, Pet, G7, and Stei for periods > 700 years, from 700 to 300 years, from 300 to 100 years, and < 100 years”. From the figure above it can be seen that this is not the case. Highest peak of series “Pet” (ice core record from Antarctica) is very close to 0 (corresponding roughly to a wavelength of several thousand years) and the mentioned peak in T2 seems to be a double peak of which the weaker one seems to be better match in wavelength with the peak mentioned in T2. The mentioned peak of 499 years in T2 also seems to be a double peak and here better match seems also to be the weaker one. For both of the double peaks, it is of course difficult to estimate the situation from the graph, but it does seem that LW17 have selected the weaker ones of the mentioned double peaks to T2.

The series “Stei” (the solar activity proxy series) also shows stronger peaks than the ones mentioned in T2. Above 700 years there are two peaks clearly stronger than the mentioned 991-year peak. Also from 700 to 300 years there is one higher peak than the mentioned one.

The figure above shows also that it is easy to find matches for peaks when there are plenty of peaks to choose from. Highlighted is the selection of the peak in “Stei” that corresponds to the 188-year peak in “G7” (and in “Pet”). There are weaker peaks that are closer matches to the wavelength of 188-year peak than the highlighted 203-year peak. One of these is also clearly statistically significant at about 197 years.

Moving on past the selection of solar activity peaks, it should be noted that after LW17 have selected the peaks, they don’t do much about them. They don’t construct a representation of temperature and calculate correlations or anything like they did for temperature series but instead they just mention that the solar activity “shows the same periods” as temperature reconstruction based on the values presented in T2.

One further thing about the figure above, the solar activity series “Stei” shows lot of peaks and as discussed above, some of them are more meaningful than the ones LW17 emphasize. Why those peaks do not show up in the temperature reconstruction? This point has not been discussed by LW17.

Next step is a very curious one. They proceed to check the solar-climate connection further, but for some reason they drop their temperature reconstruction G7 and start using “Pet” which is the low-resolution ice core proxy from Antarctica. They don’t justify this at all.

The method they use here is not described in detail. They only mention that they do a “wavelet analysis”. At the end, however, their analysis here doesn’t extend beyond studying “eyesight similarities”.


In their introduction section, LW17 created a false picture of the situation of current research status of the solar activity – climate connection by citing mostly papers that support LW17 argumentation and ignoring most of the papers that show results against their argumentation. They did a not-even-half-baked analysis containing lot of flaws. In their conclusion section LW17 then suggested that their flawed results are a “confirmation” for the false picture created in the introduction section.

We can also wonder what was the point of the Fourier-inverse Fourier exercise LW17 did (with subsequent eyesight “analysis”), because if you want to demonstrate a solar-temperature correlation, then why not just compute a correlation between them directly? It is curious that they didn’t do this at least as a side-note, surely it would (or should?) have been interesting also to them.

In my opinion, LW17 is throughout bad science – biased citing, bad research methods, strange interpretation of results, etc. Having seen and studied the paper, I cannot help wondering what this quote from LW17 acknowledgements section means: “We express our thanks to the referees for valuable comments.” If the referees gave valuable comments and the resulting paper still is as bad as described above, how bad was this paper originally?


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Some curious things about Svensmark et al. reference list

Posted by Ari Jokimäki on December 22, 2017

The hypothesis of significant effect of cosmic-rays to climate has been shown wrong many times. This is a pet hypothesis of Henrik Svensmark, who continues to push papers on the subject to scientific journals. A few days ago, the journal Nature Communications published a paper of Svensmark (& co-workers). I checked out its reference list because I think that some indicators of the quality of a paper can be found simply by checking the reference list, and how references are used.

S17 reference list – first impressions

I immediately noticed a few things about S17 reference list. I made some tweets (@AGWobserver) where I mention them:

The Kulmala et al. paper I mention there is this one: “Atmospheric data over a solar cycle: no connection between galactic cosmic rays and new particle formation”. It shows results against Svensmark’s hypothesis, but it is not cited by S17. The mentioned paper list in my tweets is this one: “Papers on the non-significant role of cosmic rays in climate”.

(Note added December 27, 2017: This paragraph is incorrect – S17 cites two Laakso et al. papers and I somehow got them mixed.) One Kulmala team paper S17 cites is “Detecting charging state of ultra-fine particles: instrumental development and ambient measurements” (Laakso et al. 2007). S17 uses it in this context: “Cosmic rays are the main producers of ions in Earth’s lower atmosphere21.” (21 is the S17 reference list number for the Laakso et al. paper.) This is strange because Laakso et al. don’t say anything about cosmic rays. Cosmic rays are mentioned only in their reference list in the title of Eichkorn et al. (2002) paper, and Laakso et al. refer to it in this context: “Ion mass spectrometers have been used successfully in the studies of new particle formation in the upper atmosphere (Eichkorn et al., 2002).” Furthermore, as Svensmark’s cosmic ray hypothesis relies on ion induced nucleation, it is noteworthy that one of Laakso et al. conclusions is this: “During a large fraction of days considered here, the contribution of ion-induced nucleation to the total nucleation rate was either negligible or relatively small.” To me it seems that either S17 is citing a wrong paper here, or then the cosmic ray ion production thing is implicitly in Laakso et al. results and I just don’t see it.

S17 reference list – comparison with other paper

I decided to look S17 reference list further. I chose a comparison paper, Gordon et al. (2017, “G17”), which is a research paper on the same issue than S17. Both papers have been published and submitted to their journals during 2017, S17 in May 10 and G17 in March 24, so S17 is a bit newer in that sense. S17 was published in December 19 and G17 in August 24, so also in that sense S17 is newer. I emphasize newer here because it suggests that references in S17 reference list should be as new or newer as references in G17 reference list.

The reference list of S17 contains 39 entries while the reference list of G17 contains 85 entries. As the papers are on the same subject, it seems that S17 reference list is a little short. However, scope of G17 seems to be somewhat broader, so reference list length doesn’t necessarily tell anything.

I also compared the temporal distributions of papers in the reference lists of these two papers. Result can be seen in this graph:

It is quite clear from the graph that S17 reference list focuses on older papers than G17 reference list. highest peak of temporal distribution of S17 is 2005-2009, while corresponding highest peak of G17 is 2010-2014. Also, G17 distribution is rather sharply concentrated on the more recent times, while S17 distribution is more spread out in time, and it almost seems as if the most resent research is being avoided in S17 reference list (the share of 2015-2017 papers is very low in S17 compared to G17).

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Papers on the warming hole of the United States

Posted by Ari Jokimäki on February 8, 2017

This is a list of papers on the warming hole of the United States. The list is not complete, and will most likely be updated in future in order to make it more thorough and more representative.

The United States “warming hole”: quantifying the forced aerosol response given large internal variability (Banerjee et al. 2017)
Abstract: “Twenty-five years of large summer cooling over the southeastern United States ending in the mid-1970s coincided with rapidly increasing anthropogenic aerosol emissions. Here, we assess the claim that the cooling in that period was predominantly due to such aerosols. We utilize two 50-member sets of coupled climate model simulations, one with only anthropogenic aerosol forcings and another with all known natural and anthropogenic forcings, together with a long control integration. We show that, in the absence of aerosol forcing, none of the model simulations capture the observed surface cooling rate (∼0.56∘C decade−1), whereas with increasing aerosol emissions two (of fifty) of the simulations do. More importantly, however, we find that the cooling from aerosols (0.20° C decade−1) is insufficient to explain the observation. Our results therefore suggest that, while aerosols may have played a role, the observed cooling was a rare event that contained a large contribution from unforced internal variability.”
Citation: Banerjee A., L.M Polvani, and J.C. Fyfe (2017), The United States “warming hole’: quantifying the forced aerosol response given large internal variability, Geophys. Res. Lett., 44, doi:10.1002/2016GL071567.

Tracking regional temperature projections from the early 1990s in light of variations in regional warming, including ‘warming holes’ (Grose et al. 2017)
Abstract: “The perception of the accuracy of regional climate projections made in the early 1990s about climate change by 2030 may be influenced by how the temperature trend has changed in the 25 years since their publication. However, temperature trends over this period were influenced not only by external forcings such as greenhouse gases but also natural variations. The temperature of Southern Australia, the Sahel, South Asia and Southern Europe are currently within the warming estimates from statements in the early 1990s from the IPCC and CSIRO, assuming a linear trend between 1990 and 2030. However, northern Australia and central North America are currently at the lower limit or below these projections, having featured areas of multi-year regional cooling during global warming, sometimes called ‘warming holes’. Recent climate model simulations suggest that cooling can be expected in the recent past and near future in some regions, including in Australia and the US, and that cooling is less likely over 1990–2030 than in 1990–2015, bringing observations closer to the IPCC and CSIRO warming estimates by 2030. Cooling at the 25-year scale in some regions can be associated with cyclic variability such as the Inter-decadal Pacific Oscillation, or low trend such as in the Southern Ocean. Explicitly communicating the variability in regional warming rates in climate projections, including the possibility of regional warming ‘holes’ (or the opposite of ‘surges’ or ‘peaks’) would help to set more reliable expectations by users of those projections.”
Citation: Grose, M.R., Risbey, J.S. & Whetton, P.H. Climatic Change (2017) 140: 307. doi:10.1007/s10584-016-1840-9.

North Pacific SST Forcing on the Central United States “Warming Hole” as Simulated in CMIP5 Coupled Historical and Uncoupled AMIP Experiments (Pan et al. 2017)
Abstract: “The central United States experienced a cooling trend during the twentieth century, called the “warming hole,” most notably in the last quarter of the century when global warming accelerated. The coupled simulations of the models that participated in the Coupled Model Intercomparison Project, Phases 3 and 5 (CMIP3/5), have been unable to reproduce this abnormal cooling phenomenon satisfactorily. An unrealistic representation of the observed phasing of the Pacific Decadal Oscillation (PDO)—one of the proposed forcing mechanisms for the warming hole—in the models is considered to be one of the main causes of this effect. The CMIP5’s uncoupled Atmospheric Model Intercomparison Project (AMIP) experiment, whose duration approximately coincides with the peak warming hole cooling period, provides an opportunity, when compared with the coupled historical experiment, to examine the role of the variation in Pacific Ocean sea surface temperature (SST) in the warming hole’s formation and also to assess the skill of the models in simulating the teleconnection between Pacific SST and the continental climate in North America. Accordingly, this study compared AMIP and historical runs in the CMIP5 suite thereby isolating the role of SST forcing in the formation of the warming hole and its maintenance mechanisms. It was found that, even when SST forcing in the AMIP run was “perfectly” prescribed in the models, the skill of the models in simulating the warming hole cooling in the central United States showed little improvement over the historical run, in which SST is calculated interactively, even though the AMIP run overestimated the anti-correlation between temperature in the central United States and the PDO index. The fact that better simulation of the PDO phasing in the AMIP run did not translate into an improved summer cooling trend in the central United States suggests that the inability of the coupled CMIP5 models to reproduce the warming hole under the historical run is not mainly a result of the mismatch between simulated and observed PDO phasing, as believed.”
Citation: Zaitao Pan, Chunhua Shi, Sanjiv Kumar, and Zhiqiu Gao (2017) Atmosphere-Ocean, doi: 10.1080/07055900.2016.1261690.

Disappearance of the southeast U.S. “warming hole” with the late 1990s transition of the Interdecadal Pacific Oscillation (Meehl et al. 2015) [FULL TEXT]
Abstract: “Observed surface air temperatures over the contiguous U.S. for the second half of the twentieth century showed a slight cooling over the southeastern part of the country, the so-called “warming hole,” while temperatures over the rest of the country warmed. This pattern reversed after 2000. Climate model simulations show that the disappearance of the warming hole in the early 2000s is likely associated with the transition of the Interdecadal Pacific Oscillation (IPO) phase from positive to negative in the tropical Pacific in the late 1990s, coincident with the early 2000s slowdown of the warming trend in globally averaged surface air temperature. Analysis of a specified convective heating anomaly sensitivity experiment in an atmosphere-only model traces the disappearance of the warming hole to negative sea surface temperature anomalies and consequent negative precipitation and convective heating anomalies in the central equatorial Pacific Ocean associated with the negative phase of the IPO after 2000.”
Citation: Meehl, G. A., J. M. Arblaster, and C. T. Y. Chung (2015), Disappearance of the southeast U.S. “warming hole” with the late 1990s transition of the Interdecadal Pacific Oscillation, Geophys. Res. Lett., 42, 5564–5570, doi:10.1002/2015GL064586.

Sedimentary proxy evidence of a mid-Holocene hypsithermal event in the location of a current warming hole, North Carolina, USA (Tanner et al. 2015) [FULL TEXT]
Abstract: “A wetland deposit from the southern Appalachian mountains of North Carolina, USA, has been radiocarbon dated and shows continuous deposition from the early Holocene to the present. Non-coastal records of Holocene paleoenvironments are rare from the southeastern USA. Increased stable carbon isotope ratios (δ13C) of sedimentary organic matter and pollen percentages indicate warm, dry early- to mid-Holocene conditions. This interpretation is also supported by n-alkane biomarker data and bulk sedimentary C/N ratios. These warm, dry conditions coincide with a mid-Holocene hypsithermal, or altithermal, documented elsewhere in North America. Our data indicate that the southeastern USA warmed concurrently with much of the rest of the continent during the mid-Holocene. If the current “warming hole” in the southeastern USA persists, during a time of greenhouse gas-induced warming elsewhere, it will be anomalous both in space and time.”
Citation: Benjamin R. Tanner, Chad S. Lane, Elizabeth M. Martin, Robert Young, Beverly Collins (2015) Quaternary Research, Volume 83, Issue 2, March 2015, Pages 315–323, doi: 10.1016/j.yqres.2014.11.004.

Attribution of the United States “warming hole”: Aerosol indirect effect and precipitable water vapor (Yu et al. 2014) [FULL TEXT]
Abstract: “Aerosols can influence the climate indirectly by acting as cloud condensation nuclei and/or ice nuclei, thereby modifying cloud optical properties. In contrast to the widespread global warming, the central and south central United States display a noteworthy overall cooling trend during the 20th century, with an especially striking cooling trend in summertime daily maximum temperature (Tmax) (termed the U.S. “warming hole”). Here we used observations of temperature, shortwave cloud forcing (SWCF), longwave cloud forcing (LWCF), aerosol optical depth and precipitable water vapor as well as global coupled climate models to explore the attribution of the “warming hole”. We find that the observed cooling trend in summer Tmax can be attributed mainly to SWCF due to aerosols with offset from the greenhouse effect of precipitable water vapor. A global coupled climate model reveals that the observed “warming hole” can be produced only when the aerosol fields are simulated with a reasonable degree of accuracy as this is necessary for accurate simulation of SWCF over the region. These results provide compelling evidence of the role of the aerosol indirect effect in cooling regional climate on the Earth. Our results reaffirm that LWCF can warm both winter Tmax and Tmin.”
Citation: Shaocai Yu, Kiran Alapaty, Rohit Mathur, Jonathan Pleim, Yuanhang Zhang, Chris Nolte, Brian Eder, Kristen Foley & Tatsuya Nagashima (2014), Scientific Reports, 4, doi:10.1038/srep06929.

Multidecadal Climate Variability and the “Warming Hole” in North America: Results from CMIP5 Twentieth- and Twenty-First-Century Climate Simulations (Kumar et al. 2013) [FULL TEXT]
Abstract: “The ability of phase 5 of the Coupled Model Intercomparison Project (CMIP5) climate models to simulate the twentieth-century “warming hole” over North America is explored, along with the warming hole’s relationship with natural climate variability. Twenty-first-century warming hole projections are also examined for two future emission scenarios, the 8.5 and 4.5 W m−2 representative concentration pathways (RCP8.5 and RCP4.5). Simulations from 22 CMIP5 climate models were analyzed, including all their ensemble members, for a total of 192 climate realizations. A nonparametric trend detection method was employed, and an alternative perspective emphasizing trend variability. Observations show multidecadal variability in the sign and magnitude of the trend, where the twentieth-century temperature trend over the eastern United States appears to be associated with low-frequency (multidecadal) variability in the North Atlantic temperatures. Most CMIP5 climate models simulate significantly lower “relative power” in the North Atlantic multidecadal oscillations than observed. Models that have relatively higher skill in simulating the North Atlantic multidecadal oscillation also are more likely to reproduce the warming hole. It was also found that the trend variability envelope simulated by multiple CMIP5 climate models brackets the observed warming hole. Based on the multimodel analysis, it is found that in the twenty-first-century climate simulations the presence or absence of the warming hole depends on future emission scenarios; the RCP8.5 scenario indicates a disappearance of the warming hole, whereas the RCP4.5 scenario shows some chance (10%–20%) of the warming hole’s reappearance in the latter half of the twenty-first century, consistent with CO2 stabilization.”
Citation: Sanjiv Kumar, James Kinter, Paul A. Dirmeyer, Zaitao Pan, Jennifer Adams (2013), Journal of Climate, 26, 11, 3511-3527, doi: 10.1175/JCLI-D-12-00535.1.

Intermodel Variability and Mechanism Attribution of Central and Southeastern U.S. Anomalous Cooling in the Twentieth Century as Simulated by CMIP5 Models (Pan et al. 2013) [FULL TEXT]
Abstract: “Some parts of the United States, especially the southeastern and central portion, cooled by up to 2°C during the twentieth century, while the global mean temperature rose by 0.6°C (0.76°C from 1901 to 2006). Studies have suggested that the Pacific decadal oscillation (PDO) and the Atlantic multidecadal oscillation (AMO) may be responsible for this cooling, termed the “warming hole” (WH), while other works reported that regional-scale processes such as the low-level jet and evapotranspiration contribute to the abnormity. In phase 3 of the Coupled Model Intercomparison Project (CMIP3), only a few of the 53 simulations could reproduce the cooling. This study analyzes newly available simulations in experiments from phase 5 of the Coupled Model Intercomparison Project (CMIP5) from 28 models, totaling 175 ensemble members. It was found that 1) only 19 out of 100 all-forcing historical ensemble members simulated negative temperature trend (cooling) over the southeast United States, with 99 members underpredicting the cooling rate in the region; 2) the missing of cooling in the models is likely due to the poor performance in simulating the spatial pattern of the cooling rather than the temporal variation, as indicated by a larger temporal correlation coefficient than spatial one between the observation and simulations; 3) the simulations with greenhouse gas (GHG) forcing only produced strong warming in the central United States that may have compensated the cooling; and 4) the all-forcing historical experiment compared with the natural-forcing-only experiment showed a well-defined WH in the central United States, suggesting that land surface processes, among others, could have contributed to the cooling in the twentieth century.”
Citation: Zaitao Pan, Xiaodong Liu, Sanjiv Kumar, Zhiqiu Gao, James Kinter (2013) Journal of Climate, 26, 17, 6215-6237, doi: 10.1175/JCLI-D-12-00559.1.

Mechanisms Contributing to the Warming Hole and the Consequent U.S. East–West Differential of Heat Extremes (Meehl et al. 2012) [FULL TEXT]
Abstract: “A linear trend calculated for observed annual mean surface air temperatures over the United States for the second-half of the twentieth century shows a slight cooling over the southeastern part of the country, the so-called warming hole, while temperatures over the rest of the country rose significantly. This east–west gradient of average temperature change has contributed to the observed pattern of changes of record temperatures as given by the ratio of daily record high temperatures to record low temperatures with a comparable east–west gradient. Ensemble averages of twentieth-century climate simulations in the Community Climate System Model, version 3 (CCSM3), show a slight west–east warming gradient but no warming hole. A warming hole appears in only several ensemble members in the Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset and in one ensemble member of simulated twentieth-century climate in CCSM3. In this model the warming hole is produced mostly from internal decadal time-scale variability originating mainly from the equatorial central Pacific associated with the Interdecadal Pacific Oscillation (IPO). Analyses of a long control run of the coupled model, and specified convective heating anomaly experiments in the atmosphere-only version of the model, trace the forcing of the warming hole to positive convective heating anomalies in the central equatorial Pacific Ocean near the date line. Cold-air advection into the southeastern United States in winter, and low-level moisture convergence in that region in summer, contribute most to the warming hole in those seasons. Projections show a disappearance of the warming hole, but ongoing greater surface temperature increases in the western United States compared to the eastern United States.”
Citation: Gerald A. Meehl, Julie M. Arblaster, Grant Branstator (2012) Journal of Climate, 25, 18, 6394-6408, doi: 10.1175/JCLI-D-11-00655.1.

Can CGCMs Simulate the Twentieth-Century “Warming Hole” in the Central United States? (Kunkel et al. 2006) [FULL TEXT]
Abstract: “The observed lack of twentieth-century warming in the central United States (CUS), denoted here as the “warming hole,” was examined in 55 simulations driven by external historical forcings and in 19 preindustrial control (unforced) simulations from 18 coupled general circulation models (CGCMs). Twentieth-century CUS trends were positive for the great majority of simulations, but were negative, as observed, for seven simulations. Only a few simulations exhibited the observed rapid rate of warming (cooling) during 1901–40 (1940–79). Those models with multiple runs (identical forcing but different initial conditions) showed considerable intramodel variability with trends varying by up to 1.8°C century−1, suggesting that internal dynamic variability played a major role at the regional scale. The wide range of trend outcomes, particularly for those models with multiple runs, and the small number of simulations similar to observations in both the forced and unforced experiments suggest that the warming hole is not a robust response of contemporary CGCMs to the estimated external forcings. A more likely explanation based on these models is that the observed warming hole involves external forcings combined with internal dynamic variability that is much larger than typically simulated. The observed CUS temperature variations are positively correlated with North Atlantic (NA) sea surface temperatures (SSTs), and both NA SSTs and CUS temperature are negatively correlated with central equatorial Pacific (CEP) SSTs. Most models simulate rather well the connection between CUS temperature and NA SSTs. However, the teleconnections between NA and CEP SSTS and between CEP SSTs and CUS temperature are poorly simulated and the models produce substantially less NA SST variability than observed, perhaps hampering their ability to reproduce the warming hole.”
Citation: Kenneth E. Kunkel, Xin-Zhong Liang, Jinhong Zhu, and Yiruo Lin (2006) Journal of Climate, 19, 17, 4137-4153, doi: 10.1175/JCLI3848.1.

Altered hydrologic feedback in a warming climate introduces a “warming hole” (Pan et al. 2004) [FULL TEXT]
Abstract: “In the last 25 years of the 20th century most major land regions experienced a summer warming trend, but the central U.S. cooled by 0.2–0.8 K. In contrast most climate projections using GCMs show warming for all continental interiors including North America. We examined this discrepancy by using a regional climate model and found a circulation-precipitation coupling under enhanced greenhouse gas concentrations that occurs on scales too small for current GCMs to resolve well. Results show a local minimum of warming in the central U.S. (a “warming hole”) associated with changes in low-level circulations that lead to replenishment of seasonally depleted soil moisture, thereby increasing late-summer evapotranspiration and suppressing daytime maximum temperatures. These regional-scale feedback processes may partly explain the observed late 20th century temperature trend in the central U.S. and potentially could reduce the magnitude of future greenhouse warming in the region.”
Citation: Pan, Z., R. W. Arritt, E. S. Takle, W. J. Gutowski Jr., C. J. Anderson, and M. Segal (2004), Altered hydrologic feedback in a warming climate introduces a “warming hole”, Geophys. Res. Lett., 31, L17109, doi:10.1029/2004GL020528.

General circulation model simulations of recent cooling in the east-central United States (Robinson et al. 2002) [FULL TEXT]
Abstract: “In ensembles of retrospective general circulation model (GCM) simulations, surface temperatures in the east-central United States cool between 1951 and 1997. This cooling, which is broadly consistent with observed surface temperatures, is present in GCM experiments driven by observed time varying sea-surface temperatures (SSTs) in the tropical Pacific, whether or not increasing greenhouse gases and other time varying climate forcings are included. Here we focus on ensembles with fixed radiative forcing and with observed varying SST in different regions. In these experiments the trend and variability in east-central U.S. surface temperatures are tied to tropical Pacific SSTs. Warm tropical Pacific SSTs cool U.S. temperatures by diminishing solar heating through an increase in cloud cover. These associations are embedded within a year-round response to warm tropical Pacific SST that features tropospheric warming throughout the tropics and regions of tropospheric cooling in midlatitudes. Precipitable water vapor over the Gulf of Mexico and the Caribbean and the tropospheric thermal gradient across the Gulf Coast of the United States increase when the tropical Pacific is warm. In observations, recent warming in the tropical Pacific is also associated with increased precipitable water over the southeast United States. The observed cooling in the east-central United States, relative to the rest of the globe, is accompanied by increased cloud cover, though year-to-year variations in cloud cover, U.S. surface temperatures, and tropical Pacific SST are less tightly coupled in observations than in the GCM.”
Citation: Robinson, W. A., R. Reudy, and J. E. Hansen, General circulation model simulations of recent cooling in the east-central United States, J. Geophys. Res., 107(D24), 4748, doi:10.1029/2001JD001577, 2002.

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Global warming hiatus claims prebunked in 1980s and 1990s

Posted by Ari Jokimäki on January 17, 2017

Recent global warming hiatus has been a subject of intensive studies during the last ten years. But it seems that there already was some research on global warming hiatus during 1980s and 1990s (earliest studies on the issue were actually back in 1940s-1970s). This seems to have gone largely unnoticed in the scientific literature of current global warming hiatus, and it certainly seems to have gone unnoticed by climate mitigation opponents who have made claims on global warming hiatus since at least 2006 and still continue to do so.

Some time ago I stumbled on a few old papers which discussed the temperature evolution of 1940s to 1970s. In the early 20th century there had been warming which seemed to have stopped around 1940 until it continued again in the turn of 1970s and 1980s. Here I will use “global warming moratorium” to describe this early hiatus (reason for this can be found below). Below I’ll go through some of the papers in question.

Early studies on the 1940s-1970s global warming moratorium

Global surface temperature increased during the first half of the 20th century. In 1940s, this warming apparently stopped. Possibly the first to notice this was Kincer (1946):

Up to the end of 1945, records for 13 subsequent years have become available, and these are here presented, supplementary to the original data, to determine tendencies since 1932. They show that the general upward temperature trend continued for several years but that the more recent records indicate a leveling off, and even contain currently a suggestion of an impending reversal.

This was confirmed by Mitchell (1961, 1963), as described by Wigley et al. (1985):

Mitchell (1961, 1963) extended Willett’s analysis beyond 1940, improved the method of area averaging, and found that the warming prior to 1940 had subsequently become a cooling trend (as suggested earlier by Kincer [1946]).

Later, Mitchell (1970) studied the effect of anthropogenic forcings (carbon dioxide and aerosols) on the temperature evolution of 20th century. Mitchell noted on the carbon dioxide forcing:

Changes of mean atmospheric temperature due to CO2, calculated by Manabe et al. as 0.3°C per 10% change in CO2, are sufficient to account for only about one third of the observed 0.6°C warming of the earth between 1880 and 1940, but will probably have become a dominant influence on the course of planetary average temperature changes by the end of this century.

And on the global warming moratorium:

Although changes of total atmospheric dust loading may possibly be sufficient to account for the observed 0.3°C-cooling of the earth since 1940, the human-derived contribution to these loading changes is inferred to have played a very minor role in the temperature decline.

Reitan (1974) extended the temperature analysis to 1968 and reported that the global warming moratorium had continued. Brinkmann (1976) extended the analysis to 1973 and saw the first signs of global warming moratorium ending and warming resuming.

Wigley et al. (1985) mention one further point worth mentioning about the global warming moratorium:

All seasons show the same long-term trends, trends that are also common to all other land-based data sets: a warming from the 1880s to around 1940, cooling to the mid-1960s/early-1970s (less obvious in winter), and subsequent warming, beginning later in summer and autumn than in spring and winter.

According to Wigley et al. (1985), the global warming moratorium remained largely unexplained, although there had been some relatively successful attempts to explain the short-term variability in the surface temperature by volcanic aerosols and solar variations, see for example the discussion and analysis in Hansen et al. (1981) and in Gilliland (1982).

Oceans and surface temperature studies in 1980s

Watts (1985) used a simple model to suggest that changes in the rate of the deep water formation can have an effect to surface temperature:

…variations in the rate of formation of deep water can lead to fluctuations in the globally averaged surface temperature similar in magnitude to variations in the earth’s surface-air temperature that have occurred during the last several hundred years.

Gaffin et al. (1986) got similar results:

The largest features of the northern hemispheric surface land temperature record can be simulated with our climate and deep ocean feedback formulation and CO2 forcing alone.

Jones et al. (1987) studied the rapidity of carbon dioxide induced climate change. Within this study, they also looked at how changes in deep water formation affected warming caused by carbon dioxide. They created a simulation, where there was a global warming caused by carbon dioxide, and then they turned off the deep water formation in the Northern Hemisphere (because the global warming moratorium was strongest in Northern Hemisphere). This resulted in surface cooling right after the deep water formation was stopped, and later warming continued again.

In the late 1980s and early 1990s there were some other similar studies also.

The global warming moratorium discussion of early 1990s

So, it seems that at the turn of 1980s and 1990s there had been several studies suggesting that oceans could have considerable effect on the surface temperature. At this point, there was a discussion in the scientific literature on the global warming moratorium, and this discussion has some interesting resemblance to the current global warming hiatus discussion.

Watts and Morantine (1991), in an editorial of Springer’s journal Climatic Change, reviewed the research which I already have discussed above. They noted the possibility of energy transfer between the surface and the deep ocean and concluded:

It is entirely possible that the greenhouse gas climate change signal is alive and well and hiding in the ocean intermediate waters, having reached there because of increased upwelling, or by some other mechanism that could effectively transport heat from the upper layers of the ocean into the huge thermal reservoir of the intermediate and deep ocean.

Kellogg (1993) revisited the issue, also in the same journal, with a letter named as “An Apparent Moratorium on the Greenhouse Warming Due to the Deep Ocean”. Kellogg described some new observational evidence for the ocean’s role in the issue. Based on this he suggested:

…oceans could sequester a significant part of the incremental greenhouse-generated heat over a period of a few decades, a period during which the surface warming would be curtailed.

Kellogg also discussed some issues relating to timing of the global warming moratorium and what would have happened if oceans wouldn’t have had a role in the surface temperature. Relating to the current global warming hiatus discussion, Kellogg made an interesting note:

One of the arguments most frequently advanced by the skeptics is that the observed warming in this century should have been larger, based on climate models that do not take account of ocean circulations, and that there should theoretically have been no such ‘moratorium’ between 1940 and 1975.

Kellogg then notes that if the oceans played a role, there wouldn’t be such a problem.

Watts and Morantine (1993) also revisited the issue (perhaps the journal sent them Kellogg’s letter and asked for their response). There were couple of additional interesting points in their response relating to current discussion on global warming hiatus. They noted on the significance of the moratorium:

In a recent article by Galbraith and Green (1992), a series of statistical tests were performed on the global average temperature time series from 1880 to 1988 (Hansen and Lebedeff, 1987). A statistically significant trend that can be approximated by a linear term was found, and the deviation from this trend during the period between 1940 and 1970 was found to fall within the range of sample fluctuation.


Even though the surface temperature of the Earth is an important piece of information, the distribution of thermal energy is a three-dimensional problem.

What I have shown here is just a sample of all papers that were studying the issue. The research on the issue also continued after the papers presented here.

The significance for current hiatus discussion

It is clear that before 2000s there had been lot of research on the subject of short-term variability of surface temperature in a presence of long-term warming trend. The research back then also pointed to probable causes of the short-term variability.

Apparently, the first claims of global warming hiatus after 1998 were made in 2006 by well-known climate change mitigation opponents. This was obviously far too soon statistically to make those claims, and there was no indication that the claims were made with knowledge of the earlier discussion and research on the subject. It also should be noted, that the claims in question were not made in scientific literature but in popular media (a situation that has continued after that and largely continues even today).

However, lots and lots of papers have been published on the recent global warming hiatus. I have sampled the reference lists of some of them and it seems that also scientific community has largely forgot that the issue has already been studied. This seems a bit unfortunate and makes one wonder if we will have forgotten the current research when the next moratorium or pause or hiatus or whatever happens.


Waltraud A.R. Brinkmann (1976), Surface temperature trend for the Northern Hemisphere-updated, Quaternary Research, Volume 6, Issue 3, September 1976, Pages 355-358, doi:10.1016/0033-5894(67)90002-6.

Gaffin, S. R., M. I. Hoffert, and T. Volk (1986), Nonlinear coupling between surface temperature and ocean upwelling as an agent in historical climate variations, J. Geophys. Res., 91(C3), 3944–3950, doi:10.1029/JC091iC03p03944.

Gilliland, R.L. (1982), Solar, volcanic, and CO2 forcing of recent climatic changes, Climatic Change, 4: 111. doi:10.1007/BF00140585.

J. Hansen, D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind, G. Russell (1981) Climate Impact of Increasing Atmospheric Carbon Dioxide, Science 28 Aug 1981: Vol. 213, Issue 4511, pp. 957-966, DOI: 10.1126/science.213.4511.957.

Click to access hansen81sci.pdf

P. D. Jones, T. M. L. Wigley, , S. C. B. Raper (1986), The Rapidity of CO2-Induced Climatic Change: Observations, Model Results and Palaeoclimatic Implications, in Abrupt Climatic Change, Volume 216 of the series NATO ASI Series pp 47-55.

Kellogg, W.W. (1993), An apparent moratorium on the greenhouse warming due to the deep ocean, Climatic Change 25: 85. doi:10.1007/BF01094085.

Kincer, J. B. (1946), Our changing climate, Eos Trans. AGU, 27(3), 342–347, doi:10.1029/TR027i003p00342.

Mitchell, J. M. (1961), RECENT SECULAR CHANGES OF GLOBAL TEMPERATURE. Annals of the New York Academy of Sciences, 95: 235–250. doi:10.1111/j.1749-6632.1961.tb50036.x

J. Murray Mitchell Jr. (1970), A Preliminary Evaluation of Atmospheric Pollution as a Cause of the Global Temperature Fluctuation of the Past Century, 139-155. In, S.F. Singer (ed.), Global Effects of Environmental Pollution. Springer Verlag, New York, New York.

Clayton H. Reitan (1974), A climatic model of solar radiation and temperature change, Quaternary Research, Volume 4, Issue 1, March 1974, Pages 25–38,

Watts, R. G. (1985), Global climate variation due to fluctuations in the rate of deep water formation, J. Geophys. Res., 90(D5), 8067–8070, doi:10.1029/JD090iD05p08067.

Watts, R.G. & Morantine, M.C. (1991), Is the greenhouse gas-climate signal hiding in the deep ocean?, Climatic Change 18: iii. doi:10.1007/BF00142966.

Wigley, T.M.L., Angell, J.K. and Jones, P.D., 1985. Analysis of the temperature record. In: M.C. MacCracken and F.M. Luther (Eds.), Detecting the Climatic Effects of Increasing Carbon Dioxide, (DOE/ER-0235), U.S. Department of Energy, Carbon Dioxide Research Division, Washington, D.C., 55-90.

Click to access Detecting_Climate_Effects_Increasing_CO2.pdf

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Carbon dioxide – a medical view from 1866

Posted by Ari Jokimäki on December 22, 2016

I noticed a paper, “Transactions Of Branches” by Charles Trustram (1866), in The British Medical Journal. It contains an interesting passage, which I give below in its entirety. I have highlighted especially interesting parts:

“Medicine. I propose, on the present occasion, to depart from the course pursued by my predecessors, and instead of confining myself to that stale subject, medical reform, and that everyday recurring matter of medical ethics, to take a cursory glance of the progress that medicine has made since our last meeting.

With the exception of those improvements that the treatment of diseases of the nervous centres has derived from the researches of Brown-Séquard and Lockhart Clarke, and the introduction of that new instrument for testing the character of the circulation (which, by the kindness of one of our members, Dr. Clapton, is now on the table, and which I have no doubt he will kindly explain to us), medicine proper seems to have made no very important advance. Pathology, physiology, and vital chemistry, have been pursuing the usual course of verifying, correcting, or rejecting the discoveries of past days. Chemistry, in its more extended sense, has been investigating the condition of the atmosphere, and trying to determine how far its constitution, as to that condition of its oxygen called ozone, determines the spread of epidemics and the character of disease; but as yet with no great practical result. But the question must some day arise, if it have not already done so, whether there is not another constituent which is exerting an influence on the animal economy; I mean an increase, at present inappreciable, of its carbonic acid gas. You are all aware that the subject of the possible exhaustion of our coal-fields, and its relation to the future of our country, which has often been hinted at by the philosopher, has just now seriously engaged the attention of our senate, not as a matter of public health, but as one of political economy. A new senator, but an old philosopher, feeling that the consideration of the subject of the taxation of his country was one, and not the least important one, of his duties, and yet too honest to regard taxes as one of the many means of spending without regard to repaying, suggested that we should try to repay some portion at least of our national debt before we had exhausted that mine of wealth which our coal-beds give us. A new feature most certainly in politics, but one that speaks well for the coming times of legislation, and one from which I hope medicine may soon derive some advantage. “Sufficient for the day is the evil thereof,” and “After us the Deluge,” has been too long the ruling creed of Governments, at all events in matters of finance.

But, I think, had he consulted the two sciences of physiology and chemistry, he need hardly have troubled himself about the matter. They would, I think, have told him that, when our coal-beds (at all events, if there be the quantity presumed) were gone, there would be nobody left to claim or to pay; for, before even the half of the coal of the world is consumed (and I do not suppose our national energy will before that time have exhausted the stock of our own country), the atmosphere will have again assumed a condition fatal to animal life – nearly that condition which a Book, in which I trust we all believe, describes it to have had, when its density, nearly three times that of the present atmosphere, held up and divided the firmament of water that was above it from that which was below it; when the very matter of these coal-beds floated in a gaseous form round earth’s surface, waiting to be fixed and solidified by the action of a gigantic flora, and stored for the use of coming man.

From the sublime to the ridiculous is said to be but one step; and from our gigantic national debt to our own fireside, and domestic expenditure in this matter, is but a short one, and to us an equally interesting and important one. What would be our feelings, if told one snowy morning in December that we had come to our last bushel of coal? We who live near the woods of Sussex might hope to get through the winter with their aid; but we should certainly feel a strong disposition to move off to a warmer climate ere the next winter began, and leave our houses and lands to settle our debt; for, in this free country, whilst coal does last, the manufacturer will take care to have his wants supplied in spite of all forebodings.

To return to that medical point at which I hinted. Let me ask this question, Is the atmosphere suffering from the extraordinary evolution of carbonic acid gas which is now going on? Is the pigmy and stunted flora of the present age equal to its decomposition, to the absorption of the carbon which combustion is now daily producing? and if so, will it continue to be so, seeing that the spread of the human family is daily diminishing the forest growths? Must there not some day be a perceptible increase of the present proportion of carbon in the atmosphere? and may not some already inappreciable increase be the cause of the present type of disease, as distinguished from that which prevailed at the beginning of this century, and which I myself have lived long enough to witness?

May not the altered type of disease have been produced rather from the presence of a depressing agent in the shape of carbonic acid gas, than from a less vivifying condition of the oxygen or its compounds of ozone?

We all, I am sure, regret to find that that dire and fatal malady, the cholera, has again reached our shores. Though it is now nearly fifty yers since this malady first skewed itself in our dependencies, where it has pretty constantly been under the eyes of our professional brethren, and more than thirty years since it came among us, it must be confessed that, beyond treating the symptoms and succouring the powers of life, we have learned but little about it. Various plans of cure have been tried, and each has had its advocates; but as yet there has not been one that has been admitted to be the best by the general voice of the profession. I have ventured to bring this subject to your notice, because I hold that it will, should this malady again spread in this country as it did in 1832, be the duty of every one of us to try to add his mite to the elucidation of the disease or verification of any plan of treatment that may come before him. The last plan of treatment propounded, which its author calls the eliminative one, is founded on the assumption, undoubtedly a true one, that the disease is a blood-poison, and that, therefore, it is desirable to assist Nature in the efforts she makes to rid herself of the poison by mild purgatives, and not by the opiates and stimulants that have been hitherto used. It is asserted that the one rids the system of the poison, which the other locks up. Before we place implicit confidence in this view, it must, I think, be shown that the diarrhoea that generally prevails at the same time as the cholera is not choleraic, or connected with that disease, but only an accompaniment, under the influence of which the poison of cholera has a better chance of exerting its power; for most assuredly hitherto it has been set down as a fact, that the cholera has generally attacked those in whom this condition has been neglected. Now, if elimination is to be the plan, it surely ought to be applied before that storm of symptoms begins, which, however curative they may be, so frequently prove fatal by their own severity. There is unquestionably a stage of incubation, even in those cases which die ere Nature sets up this eliminative action. The poison cannot well begin its action the moment it is taken into the system. Is there, then, no symptom by which this period can be distinguished? and is there no mode by which the poison can be neutralised, ere it makes itself an integral part of the blood? Can inhalation and hypodermic injection offer us no ready means of making a quick impression on the system? Certainly, if we are to look upon spasm of the smaller pulmonary arteries as the chief of the pathological conditions, inhalation would seem to offer us the readiest mode of reaching it. There is another plan of treatment which has been suggested in our JOURNAL; namely, that of transfusion of defibrinated blood. But I think the proposers of this would have done well to have taken a leaf out of the book of that sagacious cook who advised her readers to catch the hare before deciding how it was to be dressed; for, however good this plan, it would be only the rich who could hope to get it in any extensive epidemic.

Whilst doing all we can to treat this disease, we surely should not neglect to ask why and whence it comes, and what are the conditions that favour its spread? However convinced we might have been that the first epidemic was an imported one, we have lately had unmistakable evidence that it can arise in our own country. Then whence comes the poison, and what is it? Is it gaseous or molecular? Abounding, as the sunbeam shews us our atmosphere does, with matter, we can hardly regard it, however much it may assist the propagation of the disease by the deportation of its poisonous molecules, as the source of the poison. The mode of the progress of the disease forbids that. Dirt and bad water seem its almost invariable associates; but we had these for years without cholera. May we come to a conclusion that Nature occasionally loses her power of re-combining the poisonous results of decomposition? or do some intensified electro-magnetic currents occasionally revivify some dormant changes and so evolve this poison? or does this agent occasionally act electrically on some older source which was locked up in the earth’s crust ages past. The fitfulness of the disease favours the idea, either that the poison is not always present, or not liable to be evoked by every day recurring agency. On the other hand, if we are to believe what we bear of its origin among the Arabian Pilgrims, and look at what has lately occurred on board some emigrant ships, it would almost seem, that this poison, like that of typhus, may be produced by overcrowding and bad diet. What if in the end we should find it to be a modified typhus, which, instead of attacking the brain, tries conclusions with the sympathetic? If so, spasm of artery and engorgement of veins may be more dependent on the sympathetic than the direct action of a morbid agent.”

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New research – atmospheric and oceanic circulation (October 27, 2016)

Posted by Ari Jokimäki on October 27, 2016

Some of the latest papers on atmospheric and oceanic circulation 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.


On the atmospheric response experiment to a Blue Arctic Ocean (Nakamura et al. 2016)

Abstract: We demonstrated atmospheric responses to a reduction in Arctic sea ice via simulations in which Arctic sea ice decreased stepwise from the present-day range to an ice-free range. In all cases, the tropospheric response exhibited a negative Arctic Oscillation (AO)-like pattern. An intensification of the climatological planetary-scale wave due to the present-day sea ice reduction on the Atlantic side of the Arctic Ocean induced stratospheric polar vortex weakening and the subsequent negative AO. Conversely, strong Arctic warming due to ice-free conditions across the entire Arctic Ocean induced a weakening of the tropospheric westerlies corresponding to a negative AO without troposphere-stratosphere coupling, for which the planetary-scale wave response to a surface heat source extending to the Pacific side of the Arctic Ocean was responsible. Because the resultant negative AO-like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification.

Atlantic multi-decadal oscillation influence on weather regimes over Europe and the Mediterranean in spring and summer (Zampieri et al. 2016)

Abstract: We analyze the influence of the Atlantic sea surface temperature multi-decadal variability on the day-by-day sequence of large-scale atmospheric circulation patterns (i.e. the “weather regimes”) over the Euro-Atlantic region. In particular, we examine of occurrence of weather regimes from 1871 to present. This analysis is conducted by applying a clustering technique on the daily mean sea level pressure field provided by the 20th Century Reanalysis project, which was successfully applied in other studies focused on the Atlantic Multi-decadal Oscillation (AMO). In spring and summer, results show significant changes in the frequencies of certain weather regimes associated with the phase shifts of the AMO. These changes are consistent with the seasonal surface pressure, precipitation, and temperature anomalies associated with the AMO shifts in Europe.

Ocean and atmosphere feedbacks affecting AMOC hysteresis in a GCM (Jackson et al. 2016)

Abstract: Theories suggest that the Atlantic Meridional Overturning Circulation (AMOC) can exhibit a hysteresis where, for a given input of fresh water into the north Atlantic, there are two possible states: one with a strong overturning in the north Atlantic (on) and the other with a reverse Atlantic cell (off). A previous study showed hysteresis of the AMOC for the first time in a coupled general circulation model (Hawkins et al. in Geophys Res Lett. doi:10.1029/2011GL047208, 2011). In this study we show that the hysteresis found by Hawkins et al. (2011) is sensitive to the method with which the fresh water input is compensated. If this compensation is applied throughout the volume of the global ocean, rather than at the surface, the region of hysteresis is narrower and the off states are very different: when the compensation is applied at the surface, a strong Pacific overturning cell and a strong Atlantic reverse cell develops; when the compensation is applied throughout the volume there is little change in the Pacific and only a weak Atlantic reverse cell develops. We investigate the mechanisms behind the transitions between the on and off states in the two experiments, and find that the difference in hysteresis is due to the different off states. We find that the development of the Pacific overturning cell results in greater atmospheric moisture transport into the North Atlantic, and also is likely responsible for a stronger Atlantic reverse cell. These both act to stabilize the off state of the Atlantic overturning.

Arctic amplification: does it impact the polar jet stream? (Meleshko et al. 2016)

Abstract: It has been hypothesised that the Arctic amplification of temperature changes causes a decrease in the northward temperature gradient in the troposphere, thereby enhancing the oscillation of planetary waves leading to extreme weather in mid-latitudes. To test this hypothesis, we study the response of the atmosphere to Arctic amplification for a projected summer sea-ice-free period using an atmospheric model with prescribed surface boundary conditions from a state-of-the-art Earth system model. Besides a standard global warming simulation, we also conducted a sensitivity experiment with sea ice and sea surface temperature anomalies in the Arctic. We show that when global climate warms, enhancement of the northward heat transport provides the major contribution to decrease the northward temperature gradient in the polar troposphere in cold seasons, causing more oscillation of the planetary waves. However, while Arctic amplification significantly enhances near-surface air temperature in the polar region, it is not large enough to invoke an increased oscillation of the planetary waves.

Skilful predictions of the winter North Atlantic Oscillation one year ahead (Dunstone et al. 2016)

Abstract: The winter North Atlantic Oscillation is the primary mode of atmospheric variability in the North Atlantic region and has a profound influence on European and North American winter climate. Until recently, seasonal variability of the North Atlantic Oscillation was thought to be largely driven by chaotic and inherently unpredictable processes. However, latest generation seasonal forecasting systems have demonstrated significant skill in predicting the North Atlantic Oscillation when initialized a month before the onset of winter. Here we extend skilful dynamical model predictions to more than a year ahead. The skill increases greatly with ensemble size due to a spuriously small signal-to-noise ratio in the model, and consequently larger ensembles are projected to further increase the skill in predicting the North Atlantic Oscillation. We identify two sources of skill for second-winter forecasts of the North Atlantic Oscillation: climate variability in the tropical Pacific region and predictable effects of solar forcing on the stratospheric polar vortex strength. We also identify model biases in Arctic sea ice that, if reduced, may further increase skill. Our results open possibilities for a range of new climate services, including for the transport, energy, water management and insurance sectors.

Other papers

Narrowing of the ITCZ in a warming climate: physical mechanisms (Byrne & Schneider, 2016)

Observed and simulated fingerprints of multidecadal climate variability, and their contributions to periods of global SST stagnation (Barcikowska et al. 2016)

Observed Changes in the Southern Hemispheric Circulation in May (Ivy et al. 2016)

Annual Variations of the Tropopause Height over the Tibetan Plateau Compared with those over other regions (Yang et al. 2016)

The influences of the Atlantic Multidecadal Oscillation on the Mean Strength of the North Pacific Subtropical High during Boreal Winter (Lyu et al. 2016)

The Role of Tropical Inter-Basin SST Gradients in Forcing Walker Circulation Trends (Zhang & Karnauskas, 2016)

The role of low-frequency variation in the manifestation of warming trend and ENSO amplitude (Yeo et al. 2016)

Changes in meandering of the Northern Hemisphere circulation (Di Capua & Coumou, 2016)

Direct observations of the Antarctic Slope Current transport at 113°E (Peña-Molino et al. 2016)

Accounting for Centennial Scale Variability when Detecting Changes in ENSO: a study of the Pliocene (Tindall et al. 2016)

The Quasi-Biennial Oscillation of 2015-16: Hiccup or Death Spiral? (Dunkerton, 2016)

The weakening of the ENSO–Indian Ocean Dipole (IOD) coupling strength in recent decades (Ham et al. 2016)

On the Recent Destabilization of the Gulf Stream Path downstream of Cape Hatteras (Andres, 2016)

The relationship between the Madden Julian Oscillation and the North Atlantic Oscillation (Jiang et al. 2016)

Lessened response of boreal winter stratospheric polar vortex to El Niño in recent decades (Hu et al. 2016)

Warming and weakening trends of the Kuroshio during 1993-2013 (Wang et al. 2016)

Prolonged El Niño conditions in 2014–15 and the rapid intensification of Hurricane Patricia in the eastern Pacific (Foltz et al. 2016)

Connection between Anomalous Zonal Activities of the South Asian High and Eurasian Summer Climate Anomalies (Shi & Qian, 2016)

Ranking the strongest ENSO events while incorporating SST uncertainty (Huang et al. 2016)

The influence of the Gulf Stream on wintertime European blocking (O’Reilly et al. 2016)

Projected changes in atmospheric rivers affecting Europe in CMIP5 models (Ramos et al. 2016)

Hosed vs. unhosed: interruptions of the Atlantic Meridional Overturning Circulation in a global coupled model, with and without freshwater forcing (Brown & Galbraith, 2016)

An Oceanic Heat Content Based Definition for the Pacific Decadal Oscillation (Kumar & Wen, 2016)

An investigation of the presence of atmospheric rivers over the North Pacific during planetary-scale wave life cycles and their role in Arctic warming (Baggett et al. 2016)

Alternative modelling approaches for the ENSO time series: persistence and seasonality (Gil-Alana, 2016)

Changes in the width of the tropical belt due to simple radiative forcing changes in the GeoMIP simulations (Davis et al. 2016)

Atmospheric River Landfall-Latitude Changes in Future Climate Simulations (Shields & Kiehl, 2016)

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New research – temperature (October 18, 2016)

Posted by Ari Jokimäki on October 18, 2016

Some of the latest papers on temperature (related to climate) 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.


Comparing tropospheric warming in climate models and satellite data (Santer et al. 2016)

Abstract: We use updated and improved satellite retrievals of the temperature of the mid- to upper troposphere (TMT) to address key questions about the size and significance of TMT trends, agreement with model-derived TMT values, and whether models and satellite data show similar vertical profiles of warming. A recent study claimed that TMT trends over 1979 and 2015 are three times larger in climate models than in satellite data, but did not correct for the contribution TMT trends receive from stratospheric cooling. Here we show that the average ratio of modeled and observed TMT trends is sensitive to both satellite data uncertainties and to model-data differences in stratospheric cooling. When the impact of lower stratospheric cooling on TMT is accounted for, and when the most recent versions of satellite datasets are used, the previously claimed ratio of three between simulated and observed near-global TMT trends is reduced to ≈ 1.7. Next, we assess the validity of the statement that satellite data show no significant tropospheric warming over the last 18 years. This claim is not supported by our analysis: in five out of six corrected satellite TMT records, significant global-scale tropospheric warming has occurred within the last 18 years. Finally, we address long-standing concerns regarding discrepancies in modeled and observed vertical profiles of warming in the tropical atmosphere. We show that amplification of tropical warming between the lower and mid- to upper troposphere is now in close agreement in the average of 37 climate models and in one updated satellite record.

Deep and Abyssal Ocean Warming from 35 years of Repeat Hydrography (Desbruyères et al. 2016)

Abstract: Global and regional ocean warming deeper than 2000 m is investigated using 35 years of sustained repeat hydrographic survey data starting in 1981. The global long-term temperature trend below 2000 m, representing the time period 1991–2010, is equivalent to a mean heat flux of 0.065 ± 0.040 W m−2 applied over the Earth’s surface area. The strongest warming rates are found in the abyssal layer (4000–6000 m), which contributes to one third of the total heat uptake with the largest contribution from the Southern and Pacific Oceans. A similar regional pattern is found in the deep layer (2000–4000 m), which explains the remaining two thirds of the total heat uptake yet with larger uncertainties. The global average warming rate did not change within uncertainties pre-2000 versus post-2000, whereas ocean average warming rates decreased in the Pacific and Indian Oceans and increased in the Atlantic and Southern Oceans.

The contribution of greenhouse gases to the recent slowdown in global-mean temperature trends (Checa-Garcia et al. 2016)

Abstract: The recent slowdown in the rate of increase in global-mean surface temperature (GMST) has generated extensive discussion, but little attention has been given to the contribution of time-varying trends in greenhouse gas concentrations. We use a simple model approach to quantify this contribution. Between 1985 and 2003, greenhouse gases (including well-mixed greenhouse gases, tropospheric and stratospheric ozone, and stratospheric water vapour from methane oxidation) caused a reduction in GMST trend of around 0.03–0.05 K decade−1 which is around 18%–25% of the observed trend over that period. The main contributors to this reduction are the rapid change in the growth rates of ozone-depleting gases (with this contribution slightly opposed by stratospheric ozone depletion itself) and the weakening in growth rates of methane and tropospheric ozone radiative forcing. Although CO2 is the dominant greenhouse gas contributor to GMST trends, the continued increase in CO2 concentrations offsets only about 30% of the simulated trend reduction due to these other contributors. These results emphasize that trends in non-CO2 greenhouse gas concentrations can make significant positive and negative contributions to changes in the rate of warming, and that they need to be considered more closely in analyses of the causes of such variations.

The Stancari air thermometer and the 1715–1737 record in Bologna, Italy (Camuffo et al. 2016)

Abstract: This paper is focused on the closed-tube Stancari air thermometer that was developed at the beginning of the eighteenth century as an improvement of the Amontons thermometer, and used to record the temperature in Bologna, Italy, from 1715 to 1737. The problems met with this instrument, its calibration and the building technology in the eighteenth century are discussed in order to correct the record. The used methodological approach constitutes a useful example for other early series. The analysis of this record shows that the temperature in Bologna was not different from the 1961–1990 reference period. This result is in line with the contemporary record taken in Padua, Italy, confirming that this period of the Little Ice Age was not cold in the Mediterranean area.

Twenty-five winters of unexpected Eurasian cooling unlikely due to Arctic sea-ice loss (McCusker et al. 2016)

Abstract: Surface air temperature over central Eurasia decreased over the past twenty-five winters at a time of strongly increasing anthropogenic forcing and Arctic amplification. It has been suggested that this cooling was related to an increase in cold winters due to sea-ice loss in the Barents–Kara Sea. Here we use over 600 years of atmosphere-only global climate model simulations to isolate the effect of Arctic sea-ice loss, complemented with a 50-member ensemble of atmosphere–ocean global climate model simulations allowing for external forcing changes (anthropogenic and natural) and internal variability. In our atmosphere-only simulations, we find no evidence of Arctic sea-ice loss having impacted Eurasian surface temperature. In our atmosphere–ocean simulations, we find just one simulation with Eurasian cooling of the observed magnitude but Arctic sea-ice loss was not involved, either directly or indirectly. Rather, in this simulation the cooling is due to a persistent circulation pattern combining high pressure over the Barents–Kara Sea and a downstream trough. We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s. These results improve our knowledge of high-latitude climate variability and change, with implications for our understanding of impacts in high-northern-latitude systems.

Other papers

New method of estimating temperatures near the mesopause region using meteor radar observations (Lee et al. 2016)

Estimated influence of urbanization on surface warming in Eastern China using time-varying land use data (Liao et al. 2016)

The influence of winter and summer atmospheric circulation on the variability of temperature and sea ice around Greenland (Ogi et al. 2016)

A cold and fresh ocean surface in the Nordic Seas during MIS 11: Significance for the future ocean (Kandiano et al. 2016)

Observed and projected sea surface temperature seasonal changes in the Western English Channel from satellite data and CMIP5 multi-model ensemble (L’Hévéder et al. 2016)

Historical ocean reanalyses (1900–2010) using different data assimilation strategies (Yang et al. 2016)

Analysis of the warmest Arctic winter, 2015-2016 (Cullather et al. 2016)

The influence of synoptic circulations and local processes on temperature anomalies at three French observatories (Dione et al. 2016)

Ocean atmosphere thermal decoupling in the eastern equatorial Indian ocean (Joseph et al. 2016)

Changes of the time-varying percentiles of daily extreme temperature in China (Li et al. 2016)

High atmospheric horizontal resolution eliminates the wind-driven coastal warm bias in the southeastern tropical Atlantic (Milinski et al. 2016)

Effects of Natural Variability of Seawater Temperature, Time Series Length, Decadal Trend and Instrument Precision on the Ability to Detect Temperature Trends (Schlegel & Smit, 2016)

Interhemispheric SST gradient trends in the Indian Ocean prior to and during the recent global warming hiatus (Dong & McPhaden, 2016)

Temperature and precipitation extremes in century-long gridded observations, reanalyses, and atmospheric model simulations (Donat et al. 2016)

Atmospheric structure favoring high sea surface temperatures in the western equatorial Pacific (Wirasatriya et al. 2016)

Spatial and temporal changes in daily temperature extremes in China during 1960–2011 (Shen et al. 2016)

Disaggregation of Remotely Sensed Land Surface Temperature: A New Dynamic Methodology (Zhan et al. 2016)

Impact of high-resolution sea surface temperature and urban data on estimations of surface air temperature in a regional climate (Adachi et al. 2016)

Trends of urban surface temperature and heat island characteristics in the Mediterranean (Benas et al. 2016)

Impacts of urbanization on summer climate in China: An assessment with coupled land-atmospheric modeling (Cao et al. 2016)

The impact of climatic and non-climatic factors on land surface temperature in southwestern Romania (Roşca et al. 2016)

Posted in Climate claims, Climate science | Leave a Comment »

New research – past climate (October 14, 2016)

Posted by Ari Jokimäki on October 14, 2016

Some of the latest papers on past climate changes 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.


Proxy-based Northern Hemisphere temperature reconstruction for the mid-to-late Holocene (Pei et al. 2016)

Abstract: The observed late twentieth century warming must be assessed in relation to natural long-term variations of the climatic system. Here, we present a Northern Hemisphere (NH) temperature reconstruction for the mid-to-late Holocene of the past 6000 years, based on a synthesis of existing paleo-temperature proxies that are capable of revealing centennial-scale variability. This includes 56 published temperature records across the NH land areas, with a sampling resolution ranging from 1 to 100 years and a time span of at least 1000 years. The composite plus scale (CPS) method is adopted with spatial weighting to develop the NH temperature reconstruction. Our reconstruction reveals abrupt cold epochs that match well the Bond events during the past 6000 years. The study further reveals two prominent cycles in NH temperature: 1700–2000-year cycle during the mid-to-late Holocene and 1200–1500-year cycle during the past 3500 years. Our reconstruction indicates that the late twentieth century NH temperature and its rate of warming are both unprecedentedly high over the past 5000 years. By comparing our reconstruction with the projected temperature increase scenarios, we find that temperature by the end of the twenty-first century would likely exceed any peaks during the mid-to-late Holocene.

How warm was Greenland during the last interglacial period? (Landais et al. 2016)

Abstract: The last interglacial period (LIG,~129–116 thousand years ago) provides the most recent case study of multimillennial polar warming above the preindustrial level and a response of the Greenland and Antarctic ice sheets to this warming, as well as a test bed for climate and ice sheet models. Past changes in Greenland ice sheet thickness and surface temperature during this period were recently derived from the North Greenland Eemian Ice Drilling (NEEM) ice core records, northwest Greenland. The NEEM paradox has emerged from an estimated large local warming above the preindustrial level (7.5 ± 1.8 °C at the deposition site 126 kyr ago without correction for any overall ice sheet altitude changes between the LIG and the preindustrial period) based on water isotopes, together with limited local ice thinning, suggesting more resilience of the real Greenland ice sheet than shown in some ice sheet models. Here, we provide an independent assessment of the average LIG Greenland surface warming using ice core air isotopic composition (δ15N) and relationships between accumulation rate and temperature. The LIG surface temperature at the upstream NEEM deposition site without ice sheet altitude correction is estimated to be warmer by +8.5 ± 2.5 °C compared to the preindustrial period. This temperature estimate is consistent with the 7.5 ± 1.8 °C warming initially determined from NEEM water isotopes but at the upper end of the preindustrial period to LIG temperature difference of +5.2 ± 2.3 °C obtained at the NGRIP (North Greenland Ice Core Project) site by the same method. Climate simulations performed with present-day ice sheet topography lead in general to a warming smaller than reconstructed, but sensitivity tests show that larger amplitudes (up to 5 °C) are produced in response to prescribed changes in sea ice extent and ice sheet topography.

Response of Central European SST to atmospheric pCO2 forcing during the Oligocene – A combined proxy data and numerical climate model approach (Walliser et al. 2016)

Abstract: CO2-induced global warming will affect seasonal to decadal temperature patterns. Expected changes will be particularly strong in extratropical regions where temperatures will increase at faster rates than at lower latitudes. Despite that, it is still poorly constrained how precisely short-term climate dynamics will change in a generally warmer world, particularly in nearshore surface waters in the extratropics, i.e., the ecologically most productive regions of the ocean on which many human societies depend. Specifically, a detailed knowledge of the relationship between pCO2 and seasonal SST is crucial to understand interactions between the ocean and the atmosphere. In the present investigation, we have studied for the first time how rising atmospheric pCO2 levels forced surface temperature changes in Central Europe (paleolatitude ~ 45 °N) during the mid-Oligocene (from ca. 31 to 25 Ma), a time interval of Earth history during which global conditions were comparable to those predicted for the next few centuries. For this purpose, we computed numerical climate models for the Oligocene (winter, summer, annual average) assuming an atmospheric carbon dioxide rise from 400 to 560 ppm (current level to two times pre-industrial levels, PAL) and from 400 to 840 ppm (= three times PAL), respectively. These models were compared to seasonally resolved sea surface temperatures (SST) reconstructed from δ18O values of fossil bivalve shells (Glycymeris planicostalis, G. obovata, Palliolum pictum, Arctica islandica and Isognomon maxillata sandbergeri) and shark teeth (Carcharias cuspidata, C. acutissima and Physogaleus latus) collected from the shallow water deposits of the Mainz and Kassel Basins (Germany). Multi-taxon oxygen isotope-based reconstructions suggest a gradual rise of temperatures in surface waters (upper 30 to 40 m), on average, by as much as 4 °C during the Rupelian stage followed by a 4 °C cooling during the Chattian stage. Seasonal temperature amplitudes increased by ca. 2 °C during the warmest time interval of the Rupelian stage, with warming being more pronounced during summer (5 °C) than during winter (3 °C). According to numerical climate simulations, the warming of surface waters during the early Oligocene required a CO2 increase by at least 160 ppm, i.e., 400 ppm to 560 ppm. Given that atmospheric carbon dioxide levels predicted for the near future will likely exceed this value significantly, the Early Oligocene warming gives a hint of the possible future climate in Central Europe under elevated CO2 levels.

Low Florida coral calcification rates in the Plio-Pleistocene (Brachert et al. 2016)

Abstract: In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands often allow for reconstructions of annual extension ( =  growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. This report presents the bulk density, extension rates and calcification rates of fossil reef corals which underwent minor diagenetic alteration only. The corals derive from unlithified shallow water carbonates of the Florida platform (south-eastern USA), which formed during four interglacial sea level highstands dated approximately 3.2, 2.9, 1.8, and 1.2 Ma in the mid-Pliocene to early Pleistocene. With regard to the preservation, the coral skeletons display smooth growth surfaces with minor volumes of marine aragonite cement within intra-skeletal porosity. Within the skeletal structures, voids are commonly present along centres of calcification which lack secondary cements. Mean extension rates were 0.44 ± 0.19 cm yr−1 (range 0.16 to 0.86 cm yr−1), mean bulk density was 0.96 ± 0.36 g cm−3 (range 0.55 to 1.83 g cm−3) and calcification rates ranged from 0.18 to 0.82 g cm−2 yr−1 (mean 0.38 ± 0.16 g cm−2 yr−1), values which are 50 % of modern shallow-water reef corals. To understand the possible mechanisms behind these low calcification rates, we compared the fossil calcification rates with those of modern zooxanthellate corals (z corals) from the Western Atlantic (WA) and Indo-Pacific calibrated against sea surface temperature (SST). In the fossil data, we found a widely analogous relationship with SST in z corals from the WA, i.e. density increases and extension rate decreases with increasing SST, but over a significantly larger temperature window during the Plio-Pleistocene. With regard to the environment of coral growth, stable isotope proxy data from the fossil corals and the overall structure of the ancient shallow marine communities are consistent with a well-mixed, open marine environment similar to the present-day Florida Reef Tract, but variably affected by intermittent upwelling. Upwelling along the platform may explain low rates of reef coral calcification and inorganic cementation, but is too localised to account also for low extension rates of Pliocene z corals throughout the tropical WA region. Low aragonite saturation on a more global scale in response to rapid glacial–interglacial CO2 cyclicity is also a potential factor, but Plio-Pleistocene atmospheric pCO2 is generally believed to have been broadly similar to the present day. Heat stress related to globally high interglacial SST only episodically moderated by intermittent upwelling affecting the Florida platform seems to be another likely reason for low calcification rates. From these observations we suggest some present coral reef systems to be endangered from future ocean warming.

The ‘Little Ice Age’ in the Himalaya: A review of glacier advance driven by Northern Hemisphere temperature change (Rowan, 2016)

Abstract: Northern Hemisphere cooling between 1400 and 1900 in the Common Era (CE) resulted in the expansion of glaciers during a period known as the ‘Little Ice Age’ (LIA). Early investigation of recent advances of Himalayan glaciers assumed that these events were synchronous with LIA advances identified in Europe, based on the appearance and position of moraines and without numerical age control. However, applications of Quaternary dating techniques such as terrestrial cosmogenic nuclide dating have allowed researchers to determine numerical ages for these young moraines and clarify when glacial maxima occurred. This paper reviews geochronological evidence for the last advance of glaciers in the Himalaya. The 66 ages younger than 2000 years (0–2000 CE) calculated from 138 samples collected from glacial landforms demonstrate that peak moraine building occurred between 1300 and 1600 CE, slightly earlier than the coldest period of Northern Hemisphere air temperatures. The timing of LIA advances varied spatially, likely influenced by variations in topography and meteorology across and along the mountain range. Palaeoclimate proxies indicate cooling air temperatures from 1300 CE leading to a southward shift in the Asian monsoon, increased Westerly winter precipitation and generally wetter conditions across the range around 1400 and 1800 CE. The last advance of glaciers in the Himalaya during a period of variable climate resulted from cold Northern Hemisphere air temperatures and was sustained by increased snowfall as atmospheric circulation reorganised in response to cooling during the LIA.

Other papers

Dendroclimatology and historical climatology of Voronezh region, European Russia, since 1790s (Matskovsky et al. 2016)

Can stable oxygen and hydrogen isotopes from Australian subfossil Chironomus head capsules be used as proxies for past temperature change? (Chang et al. 2016)

Global deep water circulation between 2.4 and 1.7 Ma and its connection to the onset of Northern Hemisphere Glaciation (Du et al. 2016)

Evidence of temperature and precipitation change over the past 100 years in a high-resolution pollen record from the boreal forest of Central European Russia (Olchev et al. 2016)

The Bølling-age Blomvåg Beds, western Norway: implications for the Older Dryas glacial re-advance and the age of the deglaciation (Mangerud et al. 2016)

Impact of meltwater on high-latitude early Last Interglacial climate (Stone et al. 2016)

Late Miocene global cooling and the rise of modern ecosystems (Herbert et al. 2016)

On the palaeoclimatic potential of a millennium-long oak ring width chronology from Slovakia (Prokop et al. 2016)

A 414-year tree-ring-based April–July minimum temperature reconstruction and its implications for the extreme climate events, northeast China (Lyu et al. 2016)

Interactions between climate change and human activities during the early to mid-Holocene in the eastern Mediterranean basins (Berger et al. 2016)

The effect of greenhouse gas concentrations and ice sheets on the glacial AMOC in a coupled climate model (Klockmann et al. 2016)

The MMCO-EOT conundrum: same benthic δ18O, different CO2 (Stap et al. 2016)

Bayesian hierarchical regression analysis of variations in sea surface temperature change over the past million years (Snyder, 2016)

Leaf margin analysis of Chinese woody plants and the constraints on its application to palaeoclimatic reconstruction (Li et al. 2016)

The demise of the early Eocene greenhouse – Decoupled deep and surface water cooling in the eastern North Atlantic (Bornemann et al. 2016)

Impact of ice sheet meltwater fluxes on the climate evolution at the onset of the Last Interglacial (Goelzer et al. 2016)

The Response of Phanerozoic Surface Temperature to Variations in Atmospheric Oxygen Concentration (Payne et al. 2016)

Abrupt Bølling warming and ice saddle collapse contributions to the Meltwater Pulse 1a rapid sea level rise (Gregoire et al. 2016)

Early- to mid-Holocene forest-line and climate dynamics in southern Scandes mountains inferred from contrasting megafossil and pollen data (Paus & Haugland, 2016)

Low frequency Pliocene climate variability in the eastern Nordic Seas (Risebrobakken et al. 2016)

Water and carbon stable isotope records from natural archives: a new database and interactive online platform for data browsing, visualizing and downloading (Bolliet et al. 2016)

Diagenetic disturbances of marine sedimentary records from methane-influenced environments in the Fram Strait as indications of variation in seep intensity during the last 35 000 years (Sztybor & Rasmussen, 2016)

Evidence of solar activity and El Niño signals in tree rings of Araucaria araucana and A. angustifolia in South America (Perone et al. 2016)

Simulated response of the mid-Holocene Atlantic Meridional Overturning Circulation in ECHAM6-FESOM/MPIOM (Shi & Lohmann, 2016)

Holocene fire regimes and treeline migration rates in sub-arctic Canada (Sulphur et al. 2016)

Hydroclimatic variability on the Indian-subcontinent in the past millennium: Review and assessment (Dixit & Tandon, 2016)

Interglacial/glacial changes in coccolith-rich deposition in the SW Pacific Ocean: An analogue for a warmer world? (Duncan et al. 2016)

Tibetan Plateau Geladaindong black carbon ice core record (1843‒1982): Recent increases due to higher emissions and lower snow accumulation (Jenkins et al. 2016)

Posted in Climate science, Global warming effects | Leave a Comment »

Climate related papers in Journal of the Optical Society of America

Posted by Ari Jokimäki on October 12, 2016

Journal of the Optical Society of America (JOSA) was published between 1917 and 1983. After that it continued as two journals: JOSA A: Optics and Image Science and JOSA B: Optical Physics. This selection contains 225 climate related papers published in JOSA. There are not many papers related directly to climate, but most of the papers below are studying the infrared absorption properties of greenhouse gases.

Here are the selected papers:

Feature Issue on Meteorological Optics: Foreword (Bohren et al. 1983)

Inversion of superior mirage data to compute temperature profiles (Lehn, 1983)

Colors of snow, frozen waterfalls, and icebergs (Bohren, 1983)

Rainfall-induced optical phase fluctuations in the atmosphere (Yura et al. 1983)

Telluric spectra from 4690 to 5525 Å in a humid atmosphere (Rajaratnam & Lua, 1983)

Experimental Doppler-limited spectra of the ν2 bands of H216O, H217O, H218O, and HDO by Fourier-transform spectroscopy: secondary wave-number standards between 1066 and 2296 cm−1 (Guelachvili, 1983)

Radiative properties of optically anisotropic spheres and their climatic implications (Fymat, 1982)

Spatial-frequency- and wavelength-dependent effects of aerosols on the atmospheric modulation transfer function (Kopeika, 1982)

Spatial-frequency dependence of scattered background light: The atmospheric modulation transfer function resulting from aerosols (Kopeika, 1982)

Maximum-likelihood optimization of a Fabry–Perot interferometer for thermospheric temperature and wind measurements (Jahn et al. 1982)

Wavelength variation of visible and near-infrared resolution through the atmosphere: dependence on aerosol and meteorological conditions (Kopeika et al. 1981)

Refractive-index and absorption fluctuations in the infrared caused by temperature, humidity, and pressure fluctuations (Hill et al. 1980)

Vertical path atmospheric MTF measurements (Walters et al. 1979)

Single-particle correlation techniques for remote measurement of wind speed: Aerosol condition and measurement rate (Bartlett & She, 1979)

Modified spectrum of atmospheric temperature fluctuations and its application to optical propagation (Hill & Clifford, 1978)

Adiabatic pressure dependence of the 2.7 and 1.9 μm water vapor bands (Mathai et al. 1977)

Very-high-resolution far-infrared measurements of atmospheric emission from aircraft (Carli et al. 1977)

Submillimeter wave spectroscopy of the atmosphere (Harries, 1977)

Laws of optics at high irradiance. II. Experiments with SF6 at normal incidence (Thomason & Macomber, 1977)

Infrared absorption coefficient of H2SO4 vapor from 1190 to 1260 cm−1 (Majkowski, 1977)

Optical constants of water in the infrared: Influence of temperature (Pinkley et al. 1977)

9.6 μm ozone band (ν3) intensity (Bartman et al. 1976)

Optical properties of sea water in the infrared (Pinkley & Willims, 1976)

Raman-scattering cross sections for water vapor (Penney & Lapp, 1976)

The infrared optical constants of sulfuric acid at 250 K (Pinkley & Willims, 1976)

High-resolution methane ν3-band spectra using a stabilized tunable difference-frequency laser system (Pine, 1976)

Use of rainfall-induced optical scintillations to measure path-averaged rain parameters (Wang & Clifford, 1975)

6.3 μm water-vapor-band derivatives (Hendrickson et al. 1974)

Thermodynamic derivatives of infrared absorptance (Broersma & Walls, 1974)

Absolute rotational Raman cross sections for N2, O2, and CO2 (Penney et al. 1974)

Scattering-independent determination of the thermal-emission profile of a planetary atmosphere and related radiative-equilibrium considerations (Fymat, 1974)

Broadening of infrared absorption lines at reduced temperatures, III. Nitrous oxide (Tubbs & Williams, 1973)

Balloon-borne infrared measurements of the vertical distribution of N2O in the atmosphere (Goldman et al. 1973)

Influence of Temperature on the Spectrum of Water (Hale et al. 1972)

Measurements of Turbulence Profiles in the Troposphere (Bufton et al. 1972)

Irradiance Fluctuations in Optical Transmission through the Atmosphere (Lawrence, 1972)

Intensity–Half-Width Products for Seven Lines in the 6.3-μm Water-Vapor Band (Fridovich & Kinard, 1972)

Broadening of Infrared Absorption Lines at Reduced Temperatures, II. Carbon Monoxide in an Atmosphere of Carbon Dioxide (Tubbs & Williams, 1972)

Broadening of Infrared Absorption Lines at Reduced Temperatures: Carbon Dioxide (Tubbs & Williams, 1972)

Irradiance Fluctuations in Optical Transmission through the Atmosphere (Torrieri & Taylor, 1972)

Lambert Absorption Coefficients of Water in the Infrared (Robertson & Williams, 1971)

Optical Constants of Water in the Infrared (Rusk et al. 1971)

Absorption of Infrared Radiant Energy by CO2 and H2O, V. Absorption by CO2 between 1100 and 1835 cm−1 (9.1–5.5 μm) (Burch & Gryvnak, 1971)

Dispersion of Carbon Dioxide (Old et al. 1971)

Abundance of N2O in the Atmosphere between 4.5 and 13.5 km (Goldman et al. 1970)

Line Strengths in the ν3 Band of Water Vapor (Ben-Aryeh, 1970)

Infrared Spectral Absorption Coefficients for Water Vapor (Heroet & Muiriiead, 1970)

Foreign-Gas Broadening of HF by CO2 (Shaw & Lovell, 1969)

Strengths of 31 Water-Vapor Lines between 1617 and 1429 cm−1 (Krakow & Healy, 1969)

Refractive Index of Water in the Infrared (Querry et al. 1969)

Spectral Emissivity of the 3.3-μ Band of Methane at Elevated Temperatures (Goldman et al. 1969)

Presence of HNO3 in the Upper Atmosphere (Murcray et al. 1969)

Strengths of Twenty Lines in the ν3 Band of Water Vapor (Babrov & Healy, 1969)

Spectral Emissivity of NO in the Infrared (Oppenheim et al. 1969)

Absorption of Infrared Radiant Energy by CO2 and H2O. IV. Shapes of Collision-Broadened CO2 Lines (Burch et al. 1969)

Infrared Absorptance of Ammonia—20 to 35 Microns (Walsh, 1969)

Positions, Intensities, and Widths of Water-Vapor Lines between 475 and 692 cm−1 (Izatt et al. 1969)

Model for a Clear Atmosphere (Gordon, 1969)

Determination of the Temperature Profile in an Atmosphere from its Outgoing Radiance (Chahine, 1968)

Absorption of Infrared Radiant Energy by CO2 and H2O. III. Absorption by H2O between 0.5 and 36 cm−1 (278 μ−2 cm) (Burch, 1968)

Visual Haze Observed at High Altitudes (Clark, 1968)

Radiance of Sea and Sky in the Infrared Window 800–1200 cm−1 (Saunders, 1968)

Determination of CO2 Line Parameters Using a CO2–N2–He Laser (Oppenheim & Devir, 1968)

Absorption of Infrared Radiation by CO2 and H2O. II. Absorption by CO2 between 8000 and 10 000 cm−1 (1–1.25 Microns) (Burch et al. 1968)

Low-Resolution Determination of the Strength of the 667-cm−1 CO2 Band (Harward & Patty, 1968)

Strengths of Forty-two Lines in the ν1 and ν3 Bands of Water Vapor (Babrov & Casden, 1968)

Photoionization and Absorption Coefficients of N2O (Cook et al. 1968)

Influence of Wind and Cloudiness on Terrestrial Scintillation (Paperlein, 1967)

Integrated Intensity of 3.3-μ Band of Methane (Finkman et al. 1967)

Absorption of Infrared Radiation by CO2 and H2O. Experimental Techniques (Burch et al. 1967)

Self-Broadening Effects in the Infrared Bands of Gases (Anderson et al. 1967)

High-Temperature Spectral Emissivities and Total Intensities of the 15-μ Band System of CO2 (Ludwig et al. 1966)

Indirect Method for Measuring Spectral Linewidth, with Application to N2O (Oppenheim & Goldman, 1966)

Total Absorption Cross Sections of CO and CO2 in the Region 550–200 Å (Cairns & Samson, 1966)

Infrared Spectral Reflectance of Frost (Keegan & Weidner, 1966)

Spectroradiometric and Colorimetric Characteristics of Daylight in the Southern Hemisphere: Pretoria, South Africa (Winch et al. 1966)

Transmittance of Water Vapor—14 to 20 Microns (Stauffer & Walsh, 1966)

Spectral-Emissivity Measurements of the 4.3-μ CO2 Band between 2650° and 3000°K (Ferriso et al. 1966)

Far-Infrared Spectrum of Liquid Water (Draegert et al. 1966)

Absorption of Solar Radiation by Atmospheric Carbon Dioxide (Kyle et al. 1965)

Ultraviolet Spectral Energy Distribution of Sunlight (Searle & Hirt, 1965)

Daylight and Correlated Color Temperature (Wright, 1965)

Absorption of 3.39-Micron Helium–Neon Laser Emission by Methane in the Atmosphere (Edwards & Burch, 1965)

Spectral Energy Distribution of Daylight (Condit & Grum, 1964)

Infrared Emissivity of Carbon Dioxide (2.7-μ Band) (Malkmus, 1964)

Spectral Emissivities and Integrated Intensities of the 2.7- μ CO2 Band between 1200° and 1800°K (Ferriso & Ludwig, 1964)

Abundance of Methane in the Earth’s Atmosphere (Fink et al. 1964)

Emissivity of Carbon Dioxide at 4.3 μ (Davies, 1964)

Absorption Cross Sections of Argon and Methane between 600 and 170 Å (Rustgi, 1964)

Interpretation of Infrared Spectral Absorptance Measurements and Calculations for HCl (Malkmus et al. 1964)

Errors in Spectral Absorption Measurements Due to Absorbing Species in the Atmosphere (Maclay & Babrov, 1964)

Computed Intensity and Polarization of Light Scattered Outwards from the Earth and an Overlying Aerosol (Fraser, 1964)

Variation of the Infrared Solar Spectrum between 2800 and 5100 cm−1 with Altitude (Murcray et al. 1964)

Pure Rotational Absorption Spectrum of Hydrogen Fluoride Vapor between 22 and 250 μ (Rothschild, 1964)

Broadening of the ν3 Lines of HCN Due to Argon, Carbon Dioxide, and Hydrogen Chloride (Thibault et al. 1963)

The Radiance of the Earth and its Atmosphere Measured by Interference Spectroscopy (Persky & Zachor, 1963)

Infrared Emissivity of Carbon Dioxide (4.3-μ Band) (Malkmus, 1963)

Experimental and Theoretical Infrared Spectral Absorptance of HCl at Various Temperatures (Babrov, 1963)

Cirrus Infrared Reflection Measurements (McDonald & Deltenre, 1963)

Study of the Total Absorptance near 4.5 μ by Two Samples of N2O as Their Total Pressures and N2O Concentrations Were Independently Varied (Abesl & Shaw, 1963)

On the Atmospheric Infrared Continuum (Bignell et al. 1963)

Statistical Model Applied to the Region of the ν3 Fundamental of CO2 at 1200°K (Oppenheim & Ben-Aryeh, 1963)

A Weak Telluric Band of Carbon Dioxide (Diaz, 1963)

Predicting the Distribution of Infrared Radiation from the Clear Sky (Bennett & Bennett, 1962)

Infrared Spectrum of Hydrogen Fluoride: Line Positions and Line Shapes. Part II. Treatment of Data and Results (Herget et al. 1962)

Infrared Spectrum of Hydrogen Fluoride: Line Positions and Line Shapes. Part I. Experimental Details (Herndon et al. 1962)

Absorption Bands of Carbon Dioxide from 2.8–4.2 μ (Plyler et al. 1962)

Atmospheric Scattering Coefficients in the Visible and Infrared Regions (Knestrick et al. 1962)

Abundance of N2O in the Atmosphere (Rank et al. 1962)

Distribution of Irradiance in Haze and Fog (Eldridge & Johnson, 1962)

Spectral Radiance of Sky and Terrain at Wavelengths between 1 and 20 μ. III. Terrain Measurements (Eisner et al. 1962)

Transmission and Scattering Properties of a Nevada Desert Atmosphere under Cloudy Conditions (Gibbons et al. 1962)

Some Spectral Emissivities of Water Vapor in the 2.7-μ Region (Tourin, 1961)

Highly Precise Wavelengths in the Infrared. II. HCN, N2O, and CO (Rank et al. 1961)

Measurement of Atmospheric Transmissivity using Backscattered Light from a Pulsed Light Beam (Horman, 1961)

Transmission and Scattering Properties of a Nevada Desert Atmosphere (Gibbons et al. 1961)

Evaluation of Atmospheric Aerosol Particle Size Distribution from Scattering Measurements in the Visible and Infrared (Curcio, 1961)

Study of 1.4-μ, 1.9-μ, and 6.3-μ Water Vapor Bands at High Altitudes (Murcray et al. 1961)

Spectral Radiance of Sky and Terrain at Wavelengths between 1 and 20 Microns. II. Sky Measurements (Bell et al. 1960)

Infrared Solar Spectroscopy at the Jungfraujoch (Switzerland) (Delbouille & Migeotte, 1960)

Near Infrared Atmospheric Transmission to Solar Radiation (Gates, 1960)

Vibration-Rotation Bands of N2O (Tidwell et al. 1960)

Experimental Transmission Functions for the Pure Rotation Band of Water Vapor (Palmer, 1960)

Absorption by Infrared Bands of Carbon Dioxide Gas at Elevated Pressures and Temperatures (Edwards, 1960)

Atmospheric Absorptions in the Near Infrared at High Altitudes (Murcray et al. 1960)

Distribution of Infrared Radiance over a Clear Sky (Bennett et al. 1960)

Inference of Atmospheric Structure from Remote Radiation Measurements (Kaplan, 1959)

Experimental Technique for Studying Atmospheric Turbulence (Wolfe et al. 1959)

Spectral Emissivity of Carbon Dioxide from 1800–2500 cm−1 (Plass, 1959)

Abundance of Nitrous Oxide in Ground-Level Air (Birkeland & Shaw, 1959)

Solar Spectral Irradiance and Vertical Atmospheric Attenuation in the Visible and Ultraviolet (Dunkelman & Scolnik, 1959)

Far Infrared Spectra of H2O and H2S Taken with an Interferometric Spectrograph (Vanasse et al. 1959)

Wavelength Calibrations in Infrared. Part II. Use of Atomic Lines from a Hollow Cathode Discharge Tube with Neon as Carrier Gas (Rao et al. 1959)

Wavelength Calibrations in Infrared. Part I. Some Problems Concerning the Determination of Absolute Positions of Infrared Lines (Rao et al. 1959)

Pressure Modulation of Infrared Absorption.* II. Individual Lines in Vibration-Rotation Bands (Gilfert & Williams, 1959)

Temperature Dependence of the Rayleigh Scattering Coefficient in the Atmosphere (Deirmendjian, 1958)

Near Infrared Solar Radiation Measurements by Balloon to an Altitude of 100 000 Feet (Gates et al. 1958)

Pressure Modulation of Infrared Absorption.* I. Entire Vibration-Rotation Bands (Gilfert & Williams, 1958)

Correlation of Atmospheric Transmission with Backscattering (Curcio & Knestrick, 1958)

Diffuse Transmission through Real Atmospheres (Eldridge & Johnson, 1958)

Long Path Water Vapor Spectra with Pressure Broadening. II. 29 μ to 40 μ (Palmer, 1957)

Long Path Water Vapor Spectra with Pressure Broadening. I. 20 μ to 31.7 μ (Palmer, 1957)

Some Comments on Two Articles by Taylor and Yates (Birkeland et al. 1957)

Infrared Emission Spectra of the Atmosphere between 14.5 μ and 22.5 μ (Burch & Shaw, 1957)

Atmospheric Transmission in the Infrared (Taylor & Yates, 1957)

Infrared Evidence for Atmospheric Ozone at Sea Level (Taylor & Yates, 1956)

Spectral Diffuse Reflectance of Desert Surfaces (Ashburn & Weldon, 1956)

Atmospheric Turbidity and the Transmission of Ultraviolet Sunlight (Deirmendjian & Sekera, 1956)

Thermal Radiation from the Atmosphere (Sloan et al. 1956)

Infrared Transmission of Synthetic Atmospheres.* V. Absorption Laws for Overlapping Bands (Burch et al. 1956)

Infrared Evidence for the Presence of Ozone in the Lower Atmosphere (Burch, 1956)

Infrared Transmission of Synthetic Atmospheres.* IV. Application of Theoretical Band Models (Howard et al. 1956)

Infrared Transmission of Synthetic Atmospheres.* III. Absorption by Water Vapor (Howard et al. 1956)

Infrared Transmission of Synthetic Atmospheres.* II. Absorption by Carbon Dioxide (Howard et al. 1956)

Infrared Transmission of Synthetic Atmospheres.* I. Instrumentation (Howard et al. 1956)

Horizontal Atmospheric Transmittance Measurements with a Thallous Sulfide Cell Transmissometer (Pearson & Boettner, 1956)

Results of a Recent Attempt to Record the Solar Spectrum in the Region of 900–3000 A (Jursa et al. 1955)

Observations of Solar and Lunar Radiation at 1.5 Millimeters (Sinton, 1955)

Infrared Emission Spectrum of the Atmosphere (Sloan et al. 1955)

Horizontal Attenuation of Ultraviolet Light by the Lower Atmosphere (Baum & Dunkelman, 1955)

Infrared Absorption of Liquid Water from 2 to 42 Microns (Plyler & Acquista, 1954)

Measurements of Sky Luminance Distribution at Stockholm (Hopkinson, 1954)

Investigations of Atmospheric CO at the Jungfraujoch (Benesch et al. 1953)

The Infrared Spectra of Propylene and Propylene-d6 (Lord & Venkateswarlu, 1953)

Vibrational Spectra and Calculated Thermodynamic Properties of 1,1,1,2-Tetrachloroethane and Pentachloroethane (Nielsen et al. 1953)

The Forbidden Transition ν2 in the Infrared Spectrum of Methane (Burgess et al. 1953)

Absorption Line Width in the Infrared Spectrum of the Ammonia Molecule (Adel, 1953)

The Spectrum of Nitrogen Dioxide in the 1.4–3.4μ Region and the Vibrational and Rotational Constants of the NO2 Molecule (Moore, 1953)

Rotation-Vibration Spectra of Diatomic and Simple Polyatomic Molecules with Long Absorbing PathsXI. The Spectrum of Carbon Dioxide (Co2) below 1.25μ (Herzberg & Herzberg, 1953)

The Vertical Distribution of Nitrous Oxide and Methane in the Earth’s Atmosphere (Goldberg & Müller, 1953)

The Elimination of Atmospheric Water Vapor Absorption in the Perkin-Elmer Infrared Spectrometer (Fraser, 1953)

Fine Structure of the 2ν3 Band of Methane (Rank et al. 1953)

Atmospheric Attenuation at Khartoum, Sudan (Beck et al. 1953)

An Experimental Study of Atmospheric Transmission (Curcio et al. 1953)

Near-Infrared Absorption by Entire Bands of Carbon Dioxide (Howard & Chapman, 1952)

The Influence of Field of View on Measurements of Atmospheric Transmission (Stewart & Curcio, 1952)

A Method for the Determination of Atmospheric Transmission Functions from Laboratory Absorption Measurements (Plass, 1952)

The Luminous Directional Reflectance of Snow (Middleton & Mungall, 1952)

The Pressure Dependence of the Absorption by Entire Bands of Water Vapor in the Near Infrared (Howard & Chapman, 1952)

Measurements of the Brightness of the Twilight Sky (Koomen et al. 1952)

Refractive Indices of Water Vapor and Carbon Dioxide at Low Pressure (Newbound, 1949)

Night Sky Brightness Measurements in Latitudes below 45° (Hulburt, 1949)

Elimination of Water Vapor in Infra-Red Spectrometers (Giguère & Badger, 1948)

An Estimate of Transparency of the Atmospheric Window 16 Mu to 24 Mu (Adel, 1947)

The Upper Atmosphere of the Earth (Hulburt, 1947)

Brightness and Polarization of the Daylight Sky at Various Altitudes above Sea Level (Tousey & Hulburt, 1947)

A Spectrophotometer for the Determination of the Water Vapor in a Vertical Column of the Atmosphere (Foster & Foskett, 1945)

The Determination of the Concentration of Benzene and Toluene in Air by a Spectroscopic Method (Cole, 1942)

The “Diffusing Effect” of Fog (Middleton, 1942)

Optics of Atmospheric Haze (Hulburt, 1941)

The Distribution of Energy in the Visible Spectrum of Daylight (Taylor & Kerr, 1941)

The Transmission of Infra-Red Light by Fog (Sanderson, 1940)

Transmission of Infra-Red Radiation Through Fog (Smith & Hayes, 1940)

An Estimate of the Absorption of Air in the Extreme Ultraviolet (Schneider, 1940)

Laboratory Analysis of the Selective Absorption of Light by Sea Water (Clarke & James, 1939)

The Brightness of the Twilight Sky and the Density and Temperature of the Atmosphere (Hulburt, 1938)

The Reflection and Absorption of Daylight at the Surface of the Ocean (Powell & Clarke, 1936)

A Photoelectric Method of Measuring the Transparency of the Lower Atmosphere (Byram, 1935)

Visibility Photometers for Measuring Atmospheric Transparency (Byram, 1935)

Light Absorption and Distribution of Atmospheric Ozone1,2 (Ladenburg, 1935)

Light Absorption in the Atmosphere and Its Photochemistry (Wulf, 1935)

Attenuation of Light in the Lower Atmosphere (Hulburt, 1935)

The Penetration of the Red, Green and Violet Components of Daylight into Atlantic Waters (Oster & Clarke, 1935)

Absorption of Light by Sea Water (Stephenson, 1934)

The Absorption of Ultraviolet and Visible Light by Water (Dawson & Hulburt, 1934)

Intensity and Spectral Distribution of Solar Radiation in New Orleans (Laurens & Mayerson, 1933)

The Ultraviolet Transmission Coefficient of the Earth’s Atmosphere (Rockwood & Sawyer, 1932)

On the Penetration of Daylight into the Sea (Hulburt, 1932)

The Zinc Sulphide Method of Measuring Ultraviolet Radiation and the Results of Three Years’ Observations on Baltimore Sunshine (Clark, 1931)

Ultraviolet Radiation from the Sun and Heated Tungsten (Forsythe & Christison, 1930)

A Comparison of Laboratory and Solar Wave Lengths (Burns, 1930)

On the Efficient Utilization of Solar Energy (Goddard, 1929)

Spectral Reflectances of Common Materials in the Ultraviolet Region (Luckiesh, 1929)

The Ultraviolet, Visible and Infrared Reflectivities of Snow, Sand and Other Substances (Hulburt, 1928)

The Infrared Absorption Spectra of Acetylene, Ethylene and Ethane (Levin & Meyer, 1928)

The Near Infrared Absorption Spectra of Liquid Benzene and Toluene (Barnes & Fulweiler, 1927)

On the Infrared Absorption Spectra of Several Gases (Meyer et al. 1927)

Solarimeters and Solarigraphs Simple Instruments for Direct Readings of Solar Radiation Intensity from Sun and Sky (Gorczyński, 1927)

Atmospheric Absorption and Transmission in Searchlight Practice (Langer, 1926)

Meteorological Instruments and Apparatus Employed by the United States Weather Bureau (Covert, 1925)

On a Simple Method of Recording the Total and Partial Intensities of Solar Radiation (Gorczyński, 1924)

The Infrared Absorption Spectrum of Carbon Monoxide (Lowry, 1924)

The Effect of the Diffusion and Absorption by the Atmosphere on Signal Lights and Projectors (Karrer, 1923)

Recent Measurements of Stellar and Planetary Radiation (Coblentz, 1922)

The Measurement of Solar, Sky, Nocturnal and Stellar Radiation (Coblentz, 1921)

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New research – cryosphere (October 11, 2016)

Posted by Ari Jokimäki on October 11, 2016

Some of the latest papers on climate change impacts on cryosphere 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.


Grounding line retreat of Pope, Smith, and Kohler Glaciers, West Antarctica, measured with Sentinel-1a radar interferometry data (Scheuchl et al. 2016)

Abstract: We employ Sentinel-1a C band satellite radar interferometry data in Terrain Observation with Progressive Scans mode to map the grounding line and ice velocity of Pope, Smith, and Kohler glaciers, in West Antarctica, for the years 2014–2016 and compare the results with those obtained using Earth Remote Sensing Satellites (ERS-1/2) in 1992, 1996, and 2011. We observe an ongoing, rapid grounding line retreat of Smith at 2 km/yr (40 km since 1996), an 11 km retreat of Pope (0.5 km/yr), and a 2 km readvance of Kohler since 2011. The variability in glacier retreat is consistent with the distribution of basal slopes, i.e., fast along retrograde beds and slow along prograde beds. We find that several pinning points holding Dotson and Crosson ice shelves disappeared since 1996 due to ice shelf thinning, which signal the ongoing weakening of these ice shelves. Overall, the results indicate that ice shelf and glacier retreat in this sector remain unabated.

On the recent contribution of the Greenland ice sheet to sea level change (van den Broeke et al. 2016)

Abstract: We assess the recent contribution of the Greenland ice sheet (GrIS) to sea level change. We use the mass budget method, which quantifies ice sheet mass balance (MB) as the difference between surface mass balance (SMB) and solid ice discharge across the grounding line (D). A comparison with independent gravity change observations from GRACE shows good agreement for the overlapping period 2002–2015, giving confidence in the partitioning of recent GrIS mass changes. The estimated 1995 value of D and the 1958–1995 average value of SMB are similar at 411 and 418 Gt yr−1, respectively, suggesting that ice flow in the mid-1990s was well adjusted to the average annual mass input, reminiscent of an ice sheet in approximate balance. Starting in the early to mid-1990s, SMB decreased while D increased, leading to quasi-persistent negative MB. About 60 % of the associated mass loss since 1991 is caused by changes in SMB and the remainder by D. The decrease in SMB is fully driven by an increase in surface melt and subsequent meltwater runoff, which is slightly compensated by a small (< 3 %) increase in snowfall. The excess runoff originates from low-lying (< 2000 m a.s.l.) parts of the ice sheet; higher up, increased refreezing prevents runoff of meltwater from occurring, at the expense of increased firn temperatures and depleted pore space. With a 1991–2015 average annual mass loss of ~ 0.47 ± 0.23 mm sea level equivalent (SLE) and a peak contribution of 1.2 mm SLE in 2012, the GrIS has recently become a major source of global mean sea level rise.

Tropical Pacific SST drivers of recent Antarctic sea ice trends (Purich et al. 2016)

Abstract: A strengthening of the Amundsen Sea Low from 1979-2013 has been shown to largely explain the observed increase in Antarctic sea ice concentration in the eastern Ross Sea and decrease in the Bellingshausen Sea. Here we show that while these changes are not generally seen in freely-running coupled climate model simulations, they are reproduced in simulations of two independent coupled climate models; one constrained by observed sea surface temperature anomalies in the tropical Pacific, and the other by observed surface wind-stress in the tropics. Our analysis confirms previous results and strengthens the conclusion that the phase change in the Interdecadal Pacific Oscillation from positive to negative over 1979-2013 contributed to the observed strengthening of the Amundsen Sea Low and associated pattern of Antarctic sea ice change during this period. New support for this conclusion is provided by simulated trends in spatial patterns of sea ice concentrations that are similar to those observed. Our results highlight the importance of accounting for teleconnections from low to high latitudes in both model simulations and observations of Antarctic sea ice variability and change.

Quantifying ice loss in the eastern Himalayas since 1974 using declassified spy satellite imagery (Maurer et al. 2016)

Abstract: Himalayan glaciers are important natural resources and climate indicators for densely populated regions in Asia. Remote sensing methods are vital for evaluating glacier response to changing climate over the vast and rugged Himalayan region, yet many platforms capable of glacier mass balance quantification are somewhat temporally limited due to typical glacier response times. We here rely on declassified spy satellite imagery and ASTER data to quantify surface lowering, ice volume change, and geodetic mass balance during 1974–2006 for glaciers in the eastern Himalayas, centered on the Bhutan–China border. The wide range of glacier types allows for the first mass balance comparison between clean, debris, and lake-terminating (calving) glaciers in the region. Measured glaciers show significant ice loss, with an estimated mean annual geodetic mass balance of −0.13 ± 0.06 m w.e. yr−1 (meters of water equivalent per year) for 10 clean-ice glaciers, −0.19 ± 0.11 m w.e. yr−1 for 5 debris-covered glaciers, −0.28 ± 0.10 m w.e. yr−1 for 6 calving glaciers, and −0.17±0.05 m w.e. yr−1 for all glaciers combined. Contrasting hypsometries along with melt pond, ice cliff, and englacial conduit mechanisms result in statistically similar mass balance values for both clean-ice and debris-covered glacier groups. Calving glaciers comprise 18 % (66 km2) of the glacierized area yet have contributed 30 % (−0.7 km3) to the total ice volume loss, highlighting the growing relevance of proglacial lake formation and associated calving for the future ice mass budget of the Himalayas as the number and size of glacial lakes increase.

Quantifying the uncertainty in historical and future simulations of Northern Hemisphere spring snow cover (Thackeray et al. 2016)

Abstract: Projections of 21st century Northern Hemisphere (NH) spring snow cover extent (SCE) from two climate model ensembles are analyzed to characterize their uncertainty. The Fifth Coupled Model Intercomparison Project (CMIP5) multi-model ensemble exhibits variability due to both model differences and internal climate variability, whereas spread generated from a Canadian Earth System Model large ensemble (CanESM-LE) experiment is solely due to internal variability. The analysis shows that simulated 1981-2010 spring SCE trends are slightly weaker than observed (using an ensemble of snow products). Spring SCE is projected to decrease by -3.7±1.1% decade-1 within the CMIP5 ensemble over the 21st century. SCE loss is projected to accelerate for all spring months over the 21st century, with the exception of June (because most snow in this month has melted by the latter half of the 21st century). For 30-year spring SCE trends over the 21st century, internal variability estimated from CanESM-LE is substantial, but smaller than inter-model spread from CMIP5. Additionally, internal variability in NH extratropical land warming trends can affect SCE trends in the near-future (R2 = 0.45), while variability in winter precipitation can also have a significant (but lesser) impact on SCE trends. On the other hand, a majority of the inter-model spread is driven by differences in simulated warming (dominant in March, April, May), and snow cover available for melt (dominant in June). The strong temperature/SCE linkage suggests that model uncertainty in projections of SCE could be potentially reduced through improved simulation of spring season warming over land.

Other papers

Persistent artifacts in the NSIDC ice motion dataset and their implications for analysis (Szanyi et al. 2016)

Distributed ice thickness and glacier volume in southern South America (Carrivick et al. 2016)

Century-scale perspectives on observed and simulated Southern Ocean sea ice trends from proxy reconstructions (Hobbs et al. 2016)

Identifying dynamically induced variability in glacier mass-balance records (Christian et al. 2016)

Impacts of marine instability across the East Antarctic Ice Sheet on Southern Ocean dynamics (Phipps et al. 2016)

Effects of bryophyte and lichen cover on permafrost soil temperature at large scale (Porada et al. 2016)

Meltwater Pathways from Marine Terminating Glaciers of the Greenland Ice Sheet (Gillard et al. 2016)

Assimilation of surface velocities between 1996 and 2010 to constrain the form of the basal friction law under Pine Island Glacier (Gillet-Chaulet et al. 2016)

Linked trends in the south Pacific sea ice edge and Southern Oscillation Index (Kwok et al. 2016)

Greenland during the last interglacial: the relative importance of insolation and oceanic changes (Pedersen et al. 2016)

The impact of melt ponds on summertime microwave brightness temperatures and sea-ice concentrations (Kern et al. 2016)

The EUMETSAT sea ice concentration climate data record (Tonboe et al. 2016)

Temperature reconstruction from the length fluctuations of small glaciers in the eastern Alps (northeastern Italy) (Zecchetto et al. 2016)

Variability, trends, and predictability of seasonal sea ice retreat and advance in the Chukchi Sea (Serreze et al. 2016)

Producing cloud-free MODIS snow cover products with conditional probability interpolation and meteorological data (Dong & Menzel, 2016)

ICESat laser altimetry over small mountain glaciers (Treichler & Kääb, 2016)

Heterogeneous glacier thinning patterns over the last 40 years in Langtang Himal, Nepal (Ragettli et al. 2016)

Arctic sea ice patterns driven by the Asian Summer Monsoon (Grunseich & Wang, 2016)

Impact of climate warming on snow processes in ny-Ålesund, a polar maritime site at Svalbard (López-Moreno et al. 2016)

Variations in ice velocities of Pine Island Glacier Ice Shelf evaluated using multispectral image matching of Landsat time series data (Han et al. 2016)

Application of GRACE to the assessment of model-based estimates of monthly Greenland Ice Sheet mass balance (2003–2012) (Schlegel et al. 2016)

Near-real-time Arctic sea ice thickness and volume from CryoSat-2 (Tilling et al. 2016)

Potential for estimation of snow depth on Arctic sea ice from CryoSat-2 and SARAL/AltiKa missions (Guerreiro et al. 2016)

Sliding of temperate basal ice on a rough, hard bed: creep mechanisms, pressure melting, and implications for ice streaming (Krabbendam, 2016)

Monte Carlo modelling projects the loss of most land-terminating glaciers on Svalbard in the 21st century under RCP 8.5 forcing (Möller et al. 2016)

North-east sector of the Greenland Ice Sheet to undergo the greatest inland expansion of supraglacial lakes during the 21st century (Ignéczi et al. 2016)

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