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Land dominates the regional response to CO 2 direct radiative forcing
Author(s) -
Shaw Tiffany A.,
Voigt Aiko
Publication year - 2016
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 - 10.1002/2016gl071368
Subject(s) - radiative forcing , forcing (mathematics) , environmental science , climatology , longwave , atmospheric sciences , radiative transfer , outgoing longwave radiation , sea surface temperature , climate model , climate change , meteorology , physics , geology , convection , oceanography , quantum mechanics
In Atmospheric General Circulation Models (AGCMs) direct radiative forcing (increased CO 2 with fixed sea surface temperature) is an imperfect concept because land temperatures are not fixed. Here the response to direct radiative forcing is decomposed into increased CO 2 over ocean and land using an AGCM with spatially dependent CO 2 . The land versus ocean response is mostly linear. Consistent with previous work, ocean direct radiative forcing decreases ocean‐averaged outgoing longwave radiation, precipitation, and tropical circulation intensity; however, it cannot explain the regional response to direct radiative forcing. Increased CO 2 over land dominates the regional response via energy input over land, e.g., over deserts where there is no cloud and water vapor masking and a Rossby wave teleconnection. This mechanism operates across a range of climate perturbations, including decreased CO 2 . Previous AGCM decompositions involving direct radiative forcing and indirect sea surface temperature warming must be reinterpreted to include the importance of increased CO 2 over land.