Sensitivity of tropical cyclone intensity projections to longwave radiation

The accurate projection of tropical cyclone (TC) intensity within a warming climate remains a formidable challenge. Computational limitations require reductions in scale and complexity of high-resolution models, while coarse-resolution models may incorrectly represent critical physical processes. This study investigates the substantial influence of longwave radiation, evaluating its effects on projections in both model categories. Within the framework of an axisymmetric high-resolution model, the inclusion of radiation is likely to reduce projections of increased intensity. In the context of a 3D coarse-resolution model, the role of radiation in TC intensity, and projections of future intensity, is subject to errors that can be attributed to unresolved eyewall dynamics. This study evaluates the radiative effects on intensity projection as model grid spacing decreases from Δx ~ 50 km to Δx < 10 km. Beyond the consideration of maximum intensity, supplementary metrics, including TC strength and rapid intensification, are introduced and discussed. This study provides new understanding of the intricate interplay between longwave radiation, TC intensity projections, and the influence of model resolution.