nflwxman Posted November 12, 2013 Share Posted November 12, 2013 Another paper finds that half of the warming since the 1950s is due to ocean cycles, and thus reduces climate sensitivity to 1.3 Degrees C. http://link.springer.com/article/10.1007/s13143-014-0011-z. Read through that one. Their paper is almost entirely statistically based off of surface temperature data for the last 60 years. Essentially, they assume that the PDO was primarily responsible for the cooling between 1946-1970, while essentially ignoring the OHC drop during the same time period. Actually, they even explicitly mention that their results can not be extrapolated to OHC data. Without a proper explaination of physical mechanism this paper is a pretty weak. Link to comment Share on other sites More sharing options...
ORH_wxman Posted November 12, 2013 Share Posted November 12, 2013 Another paper finds that half of the warming since the 1950s is due to ocean cycles, and thus reduces climate sensitivity to 1.3 Degrees C. http://link.springer.com/article/10.1007/s13143-014-0011-z. It really is only showing TCR of 1.3C, not ECS....but the lower TCR value isn't all that different than a lot of other recent studies coming out that have shown ECS in the 2-2.5 range and a TCR lower than that. Link to comment Share on other sites More sharing options...
Snow_Miser Posted November 12, 2013 Author Share Posted November 12, 2013 It really is only showing TCR of 1.3C, not ECS....but the lower TCR value isn't all that different than a lot of other recent studies coming out that have shown ECS in the 2-2.5 range and a TCR lower than that. The authors are referring to the ECS not the TCR in their paper. http://www.drroyspencer.com/2013/11/our-new-paper-el-nino-warming-reduces-climate-sensitivity-to-1-3-deg-c/ Interestingly they get a sensitivity of 2.2 Degrees C, when just including anthropogenic forcing alone. The additional natural forcing reduces the climate sensitivity quite a bit. Link to comment Share on other sites More sharing options...
ORH_wxman Posted November 12, 2013 Share Posted November 12, 2013 The authors are referring to the ECS not the TCR in their paper. http://www.drroyspencer.com/2013/11/our-new-paper-el-nino-warming-reduces-climate-sensitivity-to-1-3-deg-c/ It seems like they are assuming rapid response. Link to comment Share on other sites More sharing options...
bluewave Posted November 12, 2013 Share Posted November 12, 2013 The authors are referring to the ECS not the TCR in their paper. http://www.drroyspencer.com/2013/11/our-new-paper-el-nino-warming-reduces-climate-sensitivity-to-1-3-deg-c/ Interestingly they get a sensitivity of 2.2 Degrees C, when just including anthropogenic forcing alone. The additional natural forcing reduces the climate sensitivity quite a bit. That's pretty much what the recent Masters paper shows due to increased ocean heat uptake. http://link.springer.com/article/10.1007/s00382-013-1770-4 Observational estimate of climate sensitivity from changes in the rate of ocean heat uptake and comparison to CMIP5 models Climate sensitivity is estimated based on 0–2,000 m ocean heat content and surface temperature observations from the second half of the 20th century and first decade of the 21st century, using a simple energy balance model and the change in the rate of ocean heat uptake to determine the radiative restoration strength over this time period. The relationship between this 30–50 year radiative restoration strength and longer term effective sensitivity is investigated using an ensemble of 32 model configurations from the Coupled Model Intercomparison Project phase 5 (CMIP5), suggesting a strong correlation between the two. The mean radiative restoration strength over this period for the CMIP5 members examined is 1.16 Wm−2K−1, compared to 2.05 Wm−2K−1from the observations. This suggests that temperature in these CMIP5 models may be too sensitive to perturbations in radiative forcing, although this depends on the actual magnitude of the anthropogenic aerosol forcing in the modern period. The potential change in the radiative restoration strength over longer timescales is also considered, resulting in a likely (67 %) range of 1.5–2.9 K for equilibrium climate sensitivity, and a 90 % confidence interval of 1.2–5.1 K. Link to comment Share on other sites More sharing options...
Snow_Miser Posted November 12, 2013 Author Share Posted November 12, 2013 That's pretty much what the recent Masters paper shows due to increased ocean heat uptake. http://link.springer.com/article/10.1007/s00382-013-1770-4 Observational estimate of climate sensitivity from changes in the rate of ocean heat uptake and comparison to CMIP5 models Climate sensitivity is estimated based on 0–2,000 m ocean heat content and surface temperature observations from the second half of the 20th century and first decade of the 21st century, using a simple energy balance model and the change in the rate of ocean heat uptake to determine the radiative restoration strength over this time period. The relationship between this 30–50 year radiative restoration strength and longer term effective sensitivity is investigated using an ensemble of 32 model configurations from the Coupled Model Intercomparison Project phase 5 (CMIP5), suggesting a strong correlation between the two. The mean radiative restoration strength over this period for the CMIP5 members examined is 1.16 Wm−2K−1, compared to 2.05 Wm−2K−1from the observations. This suggests that temperature in these CMIP5 models may be too sensitive to perturbations in radiative forcing, although this depends on the actual magnitude of the anthropogenic aerosol forcing in the modern period. The potential change in the radiative restoration strength over longer timescales is also considered, resulting in a likely (67 %) range of 1.5–2.9 K for equilibrium climate sensitivity, and a 90 % confidence interval of 1.2–5.1 K. The difference between the paper I posted and the Masters paper, is that the Masters paper assumes all of the recent warming is anthropogenic, which according to the paper I posted, is questionable. Link to comment Share on other sites More sharing options...
chubbs Posted November 13, 2013 Share Posted November 13, 2013 Another paper finds that half of the warming since the 1950s is due to ocean cycles, and thus reduces climate sensitivity to 1.3 Degrees C. http://link.springer.com/article/10.1007/s13143-014-0011-z. Only read the abstract but don't see how this could be definitive. Uses only a one dimensional model of the ocean with several "adjustable" parameters. Link to comment Share on other sites More sharing options...
Snow_Miser Posted November 13, 2013 Author Share Posted November 13, 2013 Only read the abstract but don't see how this could be definitive. Uses only a one dimensional model of the ocean with several "adjustable" parameters. http://www.drroyspencer.com/2013/11/our-new-paper-el-nino-warming-reduces-climate-sensitivity-to-1-3-deg-c/ Link to comment Share on other sites More sharing options...
chubbs Posted November 14, 2013 Share Posted November 14, 2013 http://www.drroyspencer.com/2013/11/our-new-paper-el-nino-warming-reduces-climate-sensitivity-to-1-3-deg-c/ After reading am still skeptical. Its a very simple approach. Why would there be a net warming over the past 60 years due to ENSO when we have covered a full PDO cycle. Link to comment Share on other sites More sharing options...
HailMan06 Posted January 14, 2015 Share Posted January 14, 2015 I was playing around with the NCEP correlation/regression maps and have a question. Is the AMO in the timeseries detrended or does it simply use the temperature of the North Atlantic with the warming signal not removed? Link to comment Share on other sites More sharing options...
StudentOfClimatology Posted January 14, 2015 Share Posted January 14, 2015 I was playing around with the NCEP correlation/regression maps and have a question. Is the AMO in the timeseries detrended or does it simply use the temperature of the North Atlantic with the warming signal not removed? It's detrended to remove AGW comtamination. There's still quite a bit of multidecadal variability there, though. Link to comment Share on other sites More sharing options...
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