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Linkage between tropical deep convection and low cloud feedback in GFDL perturbed physics experiments

Presentation Date
Thursday, December 16, 2021 at 2:00pm
Location
Convention Center - Poster Hall, D-F
Authors

Author

Abstract

The linkage between tropical deep convection and low cloud feedback is investigated using the perturbed physics experiments (PPEs) with the GFDL AM4 model. Systematic changes in large-scale circulation, precipitation, clouds and radiation are found when convective entrainment rate is modified in the deep convective parameterization. When the entrainment rate is weaker, the ascent rate strengthens in most convective regions except the Western Pacific, and the subsidence rate in the Eastern Pacific and Atlantic is also enhanced. Precipitation and clouds change correspondingly. In particular, the low cloud amount in the Eastern Pacific increases with decreasing entrainment rate. These GFDL PPEs exhibit different characteristics in terms of the sensitivity of convection to surface warming when compared to previous CESM1 PPE results. In addition, we have diagnosed several pathways through which deep convection and large-scale circulation modulate the low cloud response to surface temperature change, including the temperature-stability pathway and radiation-subsidence pathway.

Funding Program Area(s)