Thursday, 18 October 2001
Satellite microwave sensors: new tools for monitoring the kinematical, thermodynamical, and cloud microphysical processes in tropical cyclones
Fuzhong Weng, NOAA/NWS/NESDIS/ORA, Camp Springs, MD
Tropical cyclones normally developed over the vast ocean where little conventional measurements are available. The lack of observations is one of the major factors affecting the accurate prediction of tropical storms. Recently, a series of satellite microwave sensors on board various space platforms provide the most valuable information on hurricane dynamic and thermodynamic structures. This study presents the products derived from satellite microwave sensors under the hurricane environments. In particular, the data from the Advanced Microwave Sounding Unit (AMSU) on board NOAA-15 and 16 satellites are used to retrieve the profiles of atmospheric temperature, moisture and wind. However, due to the contamination of cloud and precipitation, the quality of these profiles are significantly degraded near the surface boundary. The growing concern is how the profiling capability from the satellite sensors can be extended into the lower boundary conditions in the precipitation areas. In this study, the new microwave sensors such as WindSAT/Corrolis and Conical scanning Microwave Imager and Sounder (CMIS) are demonstrated to obtain the hurricane wind vectors at the surface through full polarimetric microwave measurements.
Cloud microphysical processes are important in affecting the hurricane inner core structure and spiral precipitation bands through the latent heat releases. Satellite microwave sensors having window channels provide unique information on cloud and precipitation parameters. The Special Sensor Microwave Imager (SSM/I) is used to derive the cloud liquid water under various weather conditions. Recently, the new AMSU-B sub-millimeter wavelength channels (89 and 150 GHz) have become available and were utilized to obtain the cloud ice water path and ice particle size. The measurements of the cloud liquid and ice water paths can be quantitatively related to the surface rainfall rate. Thus, the evolution of the severe storm systems like hurricanes can be effectively monitored through these products.
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