Microphysical properties of developing versus non-developing cloud clusters during tropical cyclogenesis

The Eastern North Pacific basin averages around 16 named storms per year. The inter-tropical convergence zone in this basin provides an environment suited to the development of tropical cloud clusters. However, few of these cloud clusters develop into tropical cyclones. For this study, all cloud clusters in the eastern North Pacific basin were observed during the 2006 hurricane season using the Moderate-Resolution Imaging Spectroradiometer (MODIS). The scenes were analyzed to determine if there are any statistically significant differences in the cloud microphysics between developing and non-developing cloud clusters. Standard MODIS products include the cloud drop effective radius, cloud water path, cloud water phase, cloud top temperature and cloud top pressure. The effective radius and cloud top pressure fields were used to develop a parameter to identify regions of vertical motion in the cloud clusters. Prior to development or dissipation, the cloud clusters were screened by looking at only the updraft regions to avoid influences of the cirrus shield. In this talk we will present statistics of the 2006 season and compare differences in the microphysical parameters of developing cloud clusters compared to non-developing clusters.