Why is there a minimum in projected warming in the tropical North Atlantic Ocean?

Abstract

In IPCC projections for the 21st Century, the sea surface temperature (SST) shows several regions of minimum warming in the tropical oceans. These patterns appear both in fully coupled ocean-atmosphere general circulation models (GCMs) and also in atmospheric GCMs coupled to mixed-layer ocean models, and are robust across a multi-model ensemble. The present study focuses on the minimum warming in the tropical North Atlantic, as it has implications for the influence of greenhouse gas-induced climate change on hurricane development. The surface heat budget is analyzed in order to determine the causes for this minimum warming. It is found that the primary contribution is through the influence of the climatological mean wind speed on the efficiency of latent heat flux. In regions of high wind speed, radiative heating can be balanced by latent heat flux with a smaller change in SST than in other regions of the tropics Copyright 2009 by die American Geophysical Union.