Eastern North Pacific tropical cyclogenesis using satellite-based observations

The physical processes that cause one tropical cloud cluster to develop into a tropical cyclone while another, in similar environmental conditions, dissipates are still relatively unknown. In order to tie potential new understanding in genesis processes with an observation source that is consistent in both time and space, we have been investigating remote-sensing observations to determine potential discriminators for developing cloud clusters.

In this presentation tropical cloud clusters from the eastern North Pacific 2009 and 2010 tropical seasons are examined using multiple sources of remotely-sensed observations to isolate the differences in the cloud properties between those clusters that develop into tropical cyclones and those that do not. These differences between the two populations are then examined for insights into the physical processes associated with tropical cyclogenesis. Data used includes stitched GOES-E and GOES-W infrared satellite imagery and lightning flash counts from the Global Lightning Dataset 360. All tropical systems that develop within the inter-tropical convergence zone and surrounding eastern North Pacific basin which exist over the ocean and maintain organized convection for a minimum 72 hours are included. Initial results suggest that a higher frequency of lightning flashes in developing cloud clusters is accompanied by a higher percentage of very cold cloud tops that can be differentiated through use of these data. Analysis of these data along with a depiction of the sequence of events leading up to genesis will be presented.