Tropical Cyclone Rainfall Distribution from Satellite Observations

Heavy precipitation is always associated with Tropical Cyclones (TCs) and also one of the key factors leading to a catastrophic loss of properties and sometimes human lives. Better understanding of TC rainfall distributions could provide more valuable information to the relevant management teams for mitigating impacts of TCs. The multi-satellite sensor infusion approach is the only way to provide a global coverage of TC activities and associated precipitation measurements. There are many difference satellite-based rain retrieval algorithms, but the LEO passive microwave (PMW) and the GEO Infrared (IR) blended technique which takes advantages of accurate rain estimates from PMW and frequent sampling of IR is the best rain products for TCs because of its consistence for all TCs.

The Japan Aerospace Exploration Agency (JAXA) Global Satellite Mapping of Precipitation (GSMaP) data is applied for this study. GSMaP is the blended technique-based rain dataset in which the IR-based rain retrieval is carefully calibrated with the PMW-based rainfall and rain gauge measurements. The GSMap rain is at hourly temporal resolution and 0.1° spatial resolution over the 60 latitude zones.

All TC rainfall during 2000-2012 are extracted from GSMaP and interpolated into a polar coordinate at 0.5° azimuthal and 1 km radial resolution in order to display the TC’s spiral convective zones. TC’s moving directions and vertical wind shear conditions are extracted from the Joint Typhoon Warning Center archives. The composite rainfall distributions of TCs at each category and basin are carefully analyzed to present the basic characteristics of precipitation for each TC category and basin as well as their differences. Results demonstrate clearly the circularly zonal patterns of rain distributions for the composite TCs at each category. However, TC rainfall is mainly located in the forward quadrats along the TC’s motion direction. There are also distinct regional differences on TC rain distribution regarding to TC’s motion. In addition, the vertical wind shear has crucial impacts on TC rainfall distributions and their geographic characteristics. Detailed analyses will be presented at this conference.