Stratiform and Anvil Cloud-Radiative Forcing in Tropical Cyclogenesis

Cloud-radiative forcing (CRF) has been suggested to accelerate tropical cyclone (TC) genesis, but we do not yet understand the role of convective-scale processes in this cloud-radiative feedback. We use a convection-permitting ensemble Weather Research and Forecasting model framework to examine the hypothesis that CRF within stratiform cloud regions weakens downdrafts, allowing the environment to moisten more easily. We specifically compare our control simulations (CTL) of TC development to sensitivity tests that exclude cloud-radiative forcing (NCRF) either everywhere or just within specific cloud types. Our experiment and analysis indicate that CRF leads to fewer and weaker stratiform downdrafts and greater humidity and moist entropy in the developing TC core, implying suppressed ventilation, with stratiform and anvil CRF dominating this effect. This cloud-radiative feedback accelerates TC development by promoting faster intensification of both the mid-level vortex and surface cyclone.