Willis Eschenbach presented an excellent post at Watts Up With That titled
Willis is effectively mining the Argo data, where he documents a limit on the observed ocean surface temperatures. In his post he wrote at the end [in his section “Speculations on the mechanism”] – highlight added that
“[t]he number of temperature records peaks around 29°C, and drops quickly for temperatures above 30°C. This clearly establishes the existence of the mechanism limiting the oceanic temperatures.”
“I make no overarching claims for this mechanism. It is just one more part of the many interlocking threshold-based thermostatic mechanisms that operate at all temporal and spatial scales, from minutes to millennia and kilometres to planet-wide. The mechanisms include things like the decadal oscillations (PDO, AMO, etc), the several-year Nino/Nina swings, the seasonally opposing effects of clouds (warming the winters and cooling the summers), and the hourly changes in clouds and thunderstorms.
All of these work together to maintain the earth within a fairly narrow temperature band, with a temperature drift on the order of no more than ± 0.2% per century. It is the stability of the earth’s climate system which is impressive, not the slight rise over the last century. Until we understand the reasons for the amazing planetary temperature stability, we have no hope of understanding the slight variations in that stability.”
This self-regulation of the climate system has been studied, but the appreciation (and possible reality) of this aspect of the climate system has been essentially ignored by the IPCC and funding agencies, such as the NSF. On example of such a self-regulation was discussed by De-Zeng Sun in one of his papers, which I posted on and discussed on my weblog in
As they wrote in the Sun et al paper [highlight added]
“The extended calculation using coupled runs confirms the earlier inference from the AMIP runs that underestimating the negative feedback from cloud albedo and overestimating the positive feedback from the greenhouse effect of water vapor over the tropical Pacific during ENSO is a prevalent problem of climate models.”
In an e-mail exchange, which I reproduced in my post,their results are applicable to long time periods, such as examined by Willis. I wrote that
The message from the Sun et al. study, therefore, is that the models used to make the multi-decadal global climate projections that are reported in the IPCC report are “…that underestimating the negative feedback from cloud albedo and overestimating the positive feedback from the greenhouse effect of water vapor over the tropical Pacific during ENSO is a prevalent problem of climate models.”
See also De-Zheng’s powerpoint slide 17 in his presentation to my class in 2007 titled
where the limit on the maximum observed sea surface temperature associated with the Pacific tropical region is contrasted with the significantly higher values produced in the models.
A second example of a self-regulation is the limit on how cold the middle troposphere becomes. A limit of -40C to -45C is the cold side of the self-regulation that Willis discusses in his post. We discuss this limit on tropospheric cooling in several papers;
Chase, T.N., B. Herman, R.A. Pielke Sr., X. Zeng, and M. Leuthold, 2002: A proposed mechanism for the regulation of minimum midtropospheric temperatures in the Arctic. J. Geophys. Res., 107(D14), 10.10291/2001JD001425.
Tsukernik, M., T.N. Chase, M.C. Serreze, R.G. Barry, R. Pielke Sr., B. Herman, and X. Zeng, 2004: On the regulation of minimum mid-tropospheric temperatures in the Arctic. Geophys. Res. Letts., 31, L06112, doi:10.1029/2003GL018831.
Herman, B., M. Barlage, T.N. Chase, and R.A. Pielke Sr., 2008: Update on a proposed mechanism for the regulation of minimum mid-tropospheric and surface temperatures in the Arctic and Antarctic. J. Geophys. Res.-Atmos., 113, D24101, doi:10.1029/2008JD009799.
As we wrote in the abstract of the Chase et al 2002 paper [highlight added]
“This paper documents an observed lower extreme of midtropospheric (500 mbar) temperatures in the Arctic of approximately -45C during the winter season in several data sets. Each data set shows that the coldest air masses in the Arctic reach -45C during the fall months but seldom get much colder even into late winter despite a continued net radiative loss. We demonstrate that midtropospheric temperatures are significantly skewed toward warmer temperatures, indicating a regulatory mechanism at work. We further provide evidence that minimum Arctic midtropospheric temperatures are regulated by moist convective processes and that minimum 500 mbar temperatures are controlled to a large extent by high-latitude sea surface temperatures. The temperature -45C is the expected 500 mbar temperature in an atmosphere regulated by moist adiabatic ascent from a surface temperature of 1–2 degrees below 0C, the approximate freezing point of seawater……”
I hope Willis submits his important, much-needed analysis for publication in a leading peer-reviewed journal. We need more such analysis of the issue of self-regulation (i.e. negative feedbacks) within the climate system.