Efficiency of storm tracks an important climate parameter? The role of cloud radiative forcing in poleward heat transport

Abstract

Variability in poleward atmosphere-ocean heat transport has been suggested as one driver of climate change on long timescales. The radiative impact of clouds, particularly extratropical clouds, is an important factor in determining the equilibrium value of this heat transport in the current climate. Therefore, significant changes in cloudiness and cloud radiative forcing could potentially force equally significant adjustments in total poleward heat transport, and thus in atmospheric and/or oceanic dynamics. At the same time, these extratropical clouds and their strong radiative impact are largely the result of the atmospheric eddies that make up the storm tracks. Coincidentally, these storm track eddies also accomplish most of the extratropical poleward heat transport. At high latitudes, the annual-mean radiative cooling of these clouds is shown here to be of the same order as the atmospheric eddy heat transport convergence, and of opposite sign. Some potential implications of these points for climate change studies are discussed.