Longwave Radiative Feedback Due to Stratiform and Anvil Clouds

Studies have implicated the importance of longwave (LW) cloud-radiative forcing (CRF) in facilitating or accelerating the upscale development of tropical moist convection. While different cloud types are known to have distinct CRF, their individual roles in driving upscale development through radiative feedback is largely unexplored. We hypothesize that CRF from stratiform regions will have the greatest effect on upscale tropical convection. We test this hypothesis by analyzing output from convection-permitting ensemble Weather Research and Forecasting (WRF) model simulations of tropical cyclone formation. Using a novel column-by-column cloud classification scheme introduced herein, we use this model output to identify the relative contribution of five cloud types (shallow, congestus, and deep convection; and stratiform and anvil clouds) to the direct LW radiative forcing and the upscale development of convection via LW moist static energy variance. Results indicate that stratiform and anvil regions contribute dominantly to the domain averages of these variables.