DOI: 10.1007/s00382-012-1456-3
Scopus记录号: 2-s2.0-84874949123
论文题名: Some implications of a new approach to the water vapour feedback
作者: Ingram W.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2013
卷: 40, 期: 2017-03-04 起始页码: 925
结束页码: 933
语种: 英语
英文关键词: Climate change
; Climate feedbacks
; Climate sensitivity
; General circulation models
; Model comparison
英文摘要: The water vapour feedback is the largest physical climate feedback. It also gives the second-largest contribution to the range of uncertainty in climate sensitivity in General Circulation Models (GCMs). Tracing these differences back to their physical causes in the hope of constraining climate sensitivity requires an appropriate quantification. Yet the Intergovernmental Panel on Climate Change judge that the conventional diagnosis of a "water vapour feedback" and a "lapse rate feedback" provides little insight into differences between GCMs' climate sensitivities. We show that the conventionally diagnosed water vapour feedback is in fact formally useless for investigating differences between GCMs' climate sensitivities-the anticorrelation between conventional "water vapour feedback" and "lapse rate feedback" makes the correlation between the "water vapour feedback" and their sum insignificant: i. e. statistically, knowing this "feedback" allows one to conclude nothing about the sum and thence about climate sensitivity. This follows primarily from how little relative humidity (RH) changes with climate change in GCMs. A more detailed physical analysis concludes that the overall mean decrease of RH on warming seen in GCMs is robustly physically based. This and other physical arguments then suggest that the stronger the positive "water vapour feedback", the less sensitive climate can be expected to be. A diagnosis based on the "partly-Simpsonian" model of water vapour feedback avoids these problems. On the conventional view of the water vapour feedback, naive extrapolation of variations within present-day climate suggests that parts of our planet are close to locally reaching conditions that would allow a run-away water vapour greenhouse effect once they were extensive enough. Of course this has never occurred in geological history, and is not seen in Earth-like GCMs. Again, the "partly-Simpsonian" approach provides a simple qualitative explanation, by showing that the water vapour feedback can only cancel part of the basic Planck's Law negative feedback. © 2012 Crown Copyright. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54924
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Physics, University of Oxford, Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, United Kingdom; Hadley Centre for Climate Change, Met Office, FitzRoy Road, Exeter, EX1 3PB, United Kingdom
Recommended Citation:
Ingram W.. Some implications of a new approach to the water vapour feedback[J]. Climate Dynamics,2013-01-01,40(2017-03-04)