The impact of a continent's longitudinal extent on tropical precipitation

Abstract

We examine how the longitudinal extent of a subtropical continent impacts the distribution of tropical precipitation in two aquaplanet general circulation models. In the simpler model, the addition of land decreases evaporation and precipitation in the hemisphere with the continent, and the precipitation response scales with the continent's extent. In the more comprehensive model, tropical precipitation has zonal variation due to the downstream response of clouds to land. As the continental extent increases, this cloud response weakens and the Intertropical Convergence Zone becomes more zonal and shifts to the continent. The different precipitation responses in the two models indicate the importance of radiative feedbacks in modifying tropical circulation in models.