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Interpretation of model results that show changes in the effective climate sensitivity with time. Alternative title: Is the climate sensitivity dead? S. C. B. Raper, Alfred Wegener Institute, Germany. Definition for slab ocean AGCMs.
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Interpretation of model results that show changes in the effective climate sensitivity with time. Alternative title: Is the climate sensitivity dead? S. C. B. Raper, Alfred Wegener Institute, Germany
Definition for slab ocean AGCMs • The climate sensitivity is defined as the equilibrium warming for a doubling of the concentration of CO2, expressed as T2x = Q2x / , where Q2x is the doubled CO2 forcing (Wm-2) and is the feedback parameter (Wm-2/K). • But these mixed layer ocean models are not the ones used for transient simulations and the feedbacks/sensitivity may be different (see Boer and Yu 2003a).
Effective climate sensitivity defined • Murphy (1995) defined the ‘effective climate sensitivity’, denoted T2xeff, as the equilibrium response to a doubling of CO2 which would occur if the AOGCM was run to equilibrium with feedback strengths, realised at a particular time, held fixed. The equation for the feedback parameter then includes a heat flux below the atmosphere denoted F, = (Q - F)/ T and the effective climate sensitivity can be expressed as T2xeff = Q2x . T / (Q - F). • The effective climate sensitivity is thus a hypothetical concept even within the realm of climate modelling
Similar to CCCma In Boer and Yu (2003)? Similar to HadCM2 in Raper et al (2001)?
For use in the Policymakers Summary maybe the TCR is a more transparent and relevant metric for model comparison.
Definition used for the TAR with the MAGICC model Range used 1.7 - 4.2 K Is this an appropriate practical definition?