Two separate satellite missions now contain passive microwave sensors that enable meteorologists to study the internal structure of tropical cyclones around the world. The Special Sensor Microwave Imager(SSM/I) onboard the Defense Meteorological Satellite Program (DMSP) polar orbiters and the Tropical Rainfall Mapping Mission (TRMM) Microwave Imager (TMI) contain similar passive microwave channels. These channels permit one to view the rainbands, eyewall and eye of tropical cyclones (TC) even when upper-level clouds obscure more frequently available visible and Infrared (IR) geostationary and polar orbiter imagery.
SSM/I 85 GHz data has proven invaluable in defining TC structure and several efforts have made progress in relating this storm structure to TC intensity estimates. One limitation with SSM/I data has been the temporal gaps that can exist in storm sampling during the lifespan of a given TC. The TMI data has the potential to bridge a portion of this gap by using its 790 km swath and tropical inclination of 35 degrees to provide views of storms between SSM/I overflights. SSM/I and TMI data are being gathered for TCs around the world
and compared to map TC structure. Particular attention will be placed on the two-fold resolution increase in TMI data over that of the SSM/I and the fact the TRMM satellite also carries a precipitation radar (PR). Coincident 3-D rainrate structure from the PR will assist in understanding the SSM/I and TMI 85 GHz images as well as the lower channels that provide additional storm information.
The SSM/I and TMI data sets will be processed in near real-time for
storms worldwide, posted on the NRL-Monterey web page and utilized by the Joint Typhoon Warning Center in Guam for TC analysis. In addition, co-located visible and IR imagery from geostationary satellites around the globe will be processed and displayed for user interpretation in conjunction with the passive microwave data sets