Cloud microphysics in tropical cyclogenesis: Investigation of developing and non-developing cloud clusters

Recent advances in our understanding of mature tropical cyclones has not yielded similar advances with respect to cyclogenesis. The underlying mechanisms that cause one cold-core cloud cluster to transform into a self-sustaining warm-core system and another nearly identical cluster to dissipate are unknown. Recently we have been investigating the cloud microphysical properties of tropical cloud clusters to determine if there are underlying differences that can be detected in the cloud-top properties that can be pinned to fundamental processes during genesis.

There are two parts to this study. For the first part, we used MODIS, GOES, and Vaisala GLD360 data to differentiate microphysical properties of developing versus non-developing cloud clusters and to examine the process leading up to genesis. For the second part of the study, we used the Weather Research and Forecasting (WRF) model developed at the National Center for Atmospheric Research (NCAR) to simulate developing and non-developing cloud clusters using multiple microphysical schemes. Model output was quantitatively compared to remotely-sensed data to gain an understanding of how differences in cloud physics parameterizations ultimately affect storm intensification though changes in dynamics and thermodynamics. In this presentation, we will show statistical comparisons of the cloud properties of the developing versus non-developing cloud clusters as well as an analysis of the simulated cloud clusters compared to observations in order to better understand the microphysics that are important for tropical cyclone development.