Robust and Nonrobust Impacts of Atmospheric Cloud‐Radiative Interactions on the Tropical Circulation and Its Response to Surface Warming

Abstract

Abstract The impact of cloud‐radiative interactions on the tropical circulation and its response to surface warming are studied in aquaplanet model simulations with prescribed sea‐surface temperatures from eight global atmosphere models. Simulations with enabled and disabled cloud‐radiative interactions are compared. In a present‐day‐like climate, the presence of cloud‐radiative interactions strengthens the Hadley cell, narrows and strengthens tropical ascent, and widens subtropical descent. These cloud impacts are robust across models and are shown to be related to the energetics and mass constraints of the tropical atmosphere. Cloud‐radiative interactions have no robust impact on the circulation response to surface warming but amplify model differences in the response of the ascent and the Hadley cell strength. The lack of robust cloud impacts is consistent with the fact that surface warming‐induced changes in atmospheric cloud‐radiative effects are small compared to the cloud‐radiative effects in the present‐day‐like climate.