Tropical Cyclone Intensity and Cloud-Radiative Feedbacks in Cloud-Resolving Models, Climate Models, Reanalyses, and Satellite Observations

We investigate the importance of cloud-radiative feedbacks in TC development and the mechanisms underlying their influence across idealized cloud-resolving simulations and satellite observations, and compare this to their representation in global reanalyses and climate models. Radiative feedbacks in the context of a TC arise from interactions between spatially and temporally varying radiative heating and cooling (driven by the dependence of radiative heating and cooling rate on clouds and water vapor) and the developing TC (the circulation of which shapes the structure of clouds and water vapor). In idealized cloud-resolving simulations, tropical storm formation is delayed by a factor of two or three when radiative feedbacks are removed. In both simulations and in radiative transfer calculations based on CloudSat retrievals, radiative feedbacks are strongest in rapidly-intensifying storms and the longwave feedback contributed by ice clouds is the greatest influence. Enhanced inner-core deep-layer longwave warming anomalies in rapidly-intensifying TCs lead to a stronger radiatively-driven deep in-up-and-out overturning circulation, providing radially inward momentum fluxes and upward moisture fluxes which benefit TC development. Reanalyses and global climate models generally agree that longwave feedbacks favor TC development, particularly while the TC is still weak, but have varying estimates of their magnitude. They disagree on whether shortwave feedbacks enhance or suppress TC development; satellite observations suggest that shortwave feedbacks suppress TC development. Improving the representation of cloud-radiative feedbacks in forecast models and climate models therefore has the potential to yield critical advancements in TC prediction and projection.