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A new method for diagnosing radiative forcing and climate sensitivity
Author(s) -
Gregory J. M.,
Ingram W. J.,
Palmer M. A.,
Jones G. S.,
Stott P. A.,
Thorpe R. B.,
Lowe J. A.,
Johns T. C.,
Williams K. D.
Publication year - 2004
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 - 10.1029/2003gl018747
Subject(s) - radiative forcing , forcing (mathematics) , radiative transfer , tropopause , climate sensitivity , cloud forcing , environmental science , atmospheric sciences , climate model , sensitivity (control systems) , climatology , solar constant , atmosphere (unit) , cloud feedback , climate change , stratosphere , physics , meteorology , solar irradiance , geology , aerosol , oceanography , quantum mechanics , electronic engineering , engineering
We describe a new method for evaluating the radiative forcing, the climate feedback parameter (W m −2 K −1 ) and hence the effective climate sensitivity from any GCM experiment in which the climate is responding to a constant forcing. The method is simply to regress the top of atmosphere radiative flux against the global average surface air temperature change. This method does not require special integrations or off‐line estimates, such as for stratospheric adjustment, to obtain the forcing, and eliminates the need for double radiation calculations and tropopause radiative fluxes. We show that for CO 2 and solar forcing in a slab model and an AOGCM the method gives results consistent with those obtained by conventional methods. For a single integration it is less precise but since it does not require a steady state to be reached its precision could be improved by running an ensemble of short integrations.