Explaining Differences Between Recent Model and Satellite Tropospheric Warming Rates With Tropical SSTs

Abstract

AbstractGlobal climate models generally overestimate recent tropospheric warming trends. While a number of explanations have been suggested, their relative impacts have not been quantified. In particular, interannual and long‐term variability of tropospheric temperatures (TTT) is known to be strongly constrained by near‐surface conditions in ocean regions of deep convection. Here, we analyze the role played by tropical sea surface temperature (SST) variability in recent decades in setting TTT. We find that Coupled Model Intercomparison Project Phase 5 models and observations agree on the interannual relationship between SSTs in regions of deep, tropical convection and TTT. Over the 1979–2018 period, most of the difference between model and satellite‐based TTT trends can be explained by respective differences in SST warming trends in regions of deep convection. While large multidecadal patterns of SST variability certainly play a role, notably in the Pacific Ocean, other mechanisms may also contribute to the overestimation of recent SST warming in climate models.