Title: Investigating the Tropical Cyclone-Radiation Interaction in NASA Satellite, Reanalysis and Modeling Products: Intensification, Intensity and Diurnal Cycle
Abstract:
Tropical Cyclone (TC)-radiation interaction benefits TC development during TCs’ developing and mature stages, but estimates of TC-radiation interaction from observational measurements are still lacking. This study fills that gap by building observational estimates of TC-radiation interaction from the CloudSat Tropical Cyclone (CSTC) dataset. The inner-core longwave (LW) feedback increases with intensification rate and benefits TC development by increasing the MSE variance for the developing TCs, while the shortwave (SW) feedback plays a minor role on TC development. The LW-driven circulation also favors the spin up of the low-level vortex and moistening of the middle troposphere. Mechanism-denial experiments reveal that the presence of ice clouds, particularly their location in the upper troposphere rather than their phase, leads to the magnitude and sign of radiative feedbacks and the structure and strength of the radiatively-driven circulation. These results are utilized to validate the TC cloud-radiation interaction in TCs simulated by the Goddard Earth Observing System atmospheric model and analysis system, version 5.12.4 (GEOS5). Despite having less ice water mass by at least an order of magnitude than CSTC TCs, GEOS5 TCs experience comparable LW cloud feedback since a small amount of the upper-tropospheric ice cloud mass is sufficient to reduce the outgoing LW radiation. Though, the LW clear-sky feedback is overestimated in the GEOS5 TCs since the water vapor are overestimated. The weaker radiatively-driven circulation in GEOS5 TCs as compared to that in CSTC results from the weaker radiative anomalies at the lower troposphere. In addition, we examine the diurnal cycle of radiative feedback in the GEOS5 TCs where a diurnal cycle of LW radiative feedback is identified and affected by the data assimilation process of GEOS5 products. Both of these investigations aim to broaden our understanding of TC cloud-radiation interaction and improve the representation of TCs in numerical models.
