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High‐CO 2 cloud radiative forcing feedback over both land and ocean in a global climate model
Author(s) -
Abbot Dorian S.,
Huber Matthew,
Bousquet Gabriel,
Walker Chris C.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl036703
Subject(s) - cloud feedback , forcing (mathematics) , atmospheric sciences , environmental science , climatology , convection , climate model , cloud forcing , radiative forcing , gcm transcription factors , radiative transfer , cloud cover , latitude , radiative cooling , climate change , climate sensitivity , geology , meteorology , general circulation model , cloud computing , geography , physics , oceanography , geodesy , quantum mechanics , computer science , operating system
A positive feedback on high‐latitude winter marine climate change involving convective clouds has recently been proposed using simple models. This feedback could help explain data from equable climates, e.g., the Eocene, and might be relevant for future climate. Here this convective cloud feedback is shown to be active in an atmospheric GCM in modern configuration (CAM) at CO 2 = 2240 ppm and in a coupled GCM in Eocene configuration (CCSM) at CO 2 = 560 ppm. Changes in boundary conditions that increase surface temperature have a similar effect as increases in CO 2 concentration. It is also found that the high‐latitude winter cloud radiative forcing over land increases with increases in surface temperature due to either increased CO 2 or changes in boundary conditions, which could represent an important part of the explanation for warm continental interior winter surface temperatures during equable climates. This is due to increased low‐level layered clouds caused by increased relative humidity.