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Observational evidence against strongly stabilizing tropical cloud feedbacks
Author(s) -
Williams Ian N.,
Pierrehumbert Raymond T.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl072202
Subject(s) - environmental science , cloud forcing , cloud feedback , convection , cloud computing , atmospheric sciences , climatology , climate sensitivity , radiative transfer , climate model , buoyancy , cloud fraction , free convective layer , meteorology , climate change , cloud cover , geology , physics , computer science , oceanography , quantum mechanics , operating system
We present a method to attribute cloud radiative feedbacks to convective processes, using subcloud layer buoyancy as a diagnostic of stable and deep convective regimes. Applying this approach to tropical remote sensing measurements over years 2000–2016 shows that an inferred negative short‐term cloud feedback from deep convection was nearly offset by a positive cloud feedback from stable regimes. The net cloud feedback was within statistical uncertainty of the National Center for Atmospheric Research Community Atmosphere Model (CAM5) with historical forcings, with discrepancies in the partitioning of the cloud feedback into convective regimes. Compensation between high‐cloud responses to tropics‐wide warming in stable and unstable regimes resulted in smaller net changes in high‐cloud fraction with warming. In addition, deep convection and associated high clouds set in at warmer temperatures in response to warming, as a consequence of nearly invariant subcloud buoyancy. This invariance further constrained the magnitude of cloud radiative feedbacks and is consistent with climate model projections.