Dynamical amplification of polar warming

Abstract

This paper presents theoretical and modeling evidence suggesting that the atmospheric poleward heat transport can lead to a polar warming amplification (i) by redistributing part of the extra energy intercepted by the low-latitude atmosphere to high latitudes, and (ii) by strengthening the water vapor feedback in high latitudes. For an anthropogenic radiative forcing of 4 Wm-2, we illustrate that the dynamical amplifier contributes to about 1/4 (1/10) of the total high-latitude (global) surface warming in winter in a simple coupled atmosphere-surface moist radiative-transportive climate model. Budget analysis of the radiation fluxes at the top of the atmosphere derived from IPCC AR4 CGCM climate simulations seems to support the dynamical amplifier theory for the larger warming in high latitudes. Copyright 2005 by the American Geophysical Union.