Spread in high cloud feedback along tropical convective margins linked to changes in convective organization across scales

Tropical high cloud feedbacks exhibit considerable spread across climate models. This study applies the cloud radiative kernel technique of Zelinka et al. (2012a; 2013) to 22 models across the Coupled Model Intercomparison Project CMIP5 and CMIP6 ensembles to survey tropical high cloud feedbacks and analyze their relationships to climate sensitivity, changes to the tropical overturning circulation, and changes to deep convective organization across scales. First, the inter-model spread in tropical high cloud net, altitude, and optical depth feedbacks exhibit significant correlations to climate sensitivity in the tropical mean and on convective margins. Additionally, we find that inter-model variability in deep convective organization – at both the mesoscale and planetary scales – relates to the inter-model spread in high cloud feedbacks along convective margins. More specifically, decreases in tropical ascent area and increases in mesoscale organization of deep convection relate to more positive high cloud feedbacks, particularly within weak ascent and weak descent regimes. Increases in mesoscale organization also coincide with a greater weakening of the Pacific Walker circulation. Finally, relationships between the inter-model spread in tropical high cloud feedbacks, convective organization across scales, and sea surface temperature patterns will be discussed.