The Influence of Radiation on the Prediction of Tropical Cyclone Intensification in a Forecast Model

This study examines the influence of radiative heating on the prediction of tropical cyclone (TC) intensification in the Hurricane Weather Research and Forecasting (HWRF) model. Previous idealized modeling and observational studies demonstrated that radiative heating can substantially modulate the evolution of TC intensity. However, the relevance of this process under realistic conditions remains unclear. Here, we use observed longwave radiative heating to explore the performance of TC forecasts in HWRF simulations. The performance of TC intensity forecasts is then investigated in the context of radiative heating forecasts. In observations and HWRF forecasts, high clouds near the TC center increase the convergence of radiative fluxes. A sharp spatial gradient (≥60 W/m2) in the flux convergence from the TC center outward toward the environment is associated with subsequent TC intensification. More accurate simulation of the spatial structure of longwave radiative heating is associated with more accurate TC intensity forecasts. Plain Language Summary Satellite measurements observed larger radiation heating near the center of intensifying tropical cyclones. Previous idealized modeling studies suggest that this heating facilitates tropical cyclone development. In this study, we investigate how radiative heating affects the ability of a tropical cyclone forecast model to predict tropical cyclone intensification. Our results demonstrate that the model forecasts of intensity improve when the model better reproduces the observed spatial structure of radiative heating associated with the tropical cyclone. Key Points Tropical cyclones that intensify tend to have greater longwave convergence within the atmospheric column prior to intensification An operational forecast model can capture the signal of TC intensification in longwave radiation The ability to simulate radiation in the forecast model can influence its prediction skills of tropical cyclone intensification