loading page

The Shortwave Cloud-SST Feedback Amplifies Multi-Decadal Pacific Sea Surface Temperature Trends: Implications for Observed Cooling
  • Zachary Espinosa,
  • Mark D Zelinka
Zachary Espinosa
Department of Atmospheric Sciences, University of Washington, Lawrence Livermore National Laboratory

Corresponding Author:[email protected]

Author Profile
Mark D Zelinka
Lawrence Livermore National Laboratory

Abstract

Climate models struggle to produce sea surface temperature (SST) gradient trends in the tropical Pacific comparable to those seen recently in nature. Here, we investigate whether models systematically underestimate internally-generated SST trends by underestimating cloud feedbacks on SST gradients. A heat-budget analysis reveals coupling between cloud-radiative effects, circulation, and SST gradients in driving multi-decadal variability in the Eastern Pacific and suggests that biases in cloud feedbacks may be causing models to underestimate internal SST variability. We find that the magnitude of the cloud-SST feedback in the subtropical Southeast Pacific is correlated across models with the magnitude of Eastern Pacific multi-decadal SST variability. Using this relationship and observed feedback estimates, we estimate that internal Eastern Pacific SST variability is under-predicted in most models. Adjusting for model bias increases the likelihood of generating a cooling trend at least as large as observations in preindustrial control simulations by between ~10% and ~58%.
05 Jul 2024Submitted to ESS Open Archive
05 Jul 2024Published in ESS Open Archive