Measurements and implications for combined radar-passive microwaverainfall profiling techniques

摘要

An upcoming NASA satellite platform, the Tropical RainfallnMeasuring Mission (TRMM), represents the first opportunity tonincorporate both multifrequency passive microwave and active radarnmeasurements in its retrieval algorithms. The TRMM microwave imagern(TMI) includes many of the same passive channels as the current SpecialnSensor Microwave Imager (SSMI), with the addition of a 10.7 GHz channel.nThe 14 GHz incoherent precipitation radar (PR) scans an across-tracknswath width about one-third the width of the forward-view conical TMInscan. Therefore, the radar data arrives about a minute after the TMInscan, and the PR and TMI beams view significantly different profiles innthe atmosphere for a given on-Earth pixel location. During the 1992-1993nTOGA-COARE experiment in the western Pacific Ocean, a DC-8-basednprecipitation radar and an ER-a-based 4-channel microwave radiometerngathered data over a multitude of precipitating storm regions includingnthe forming and mature stages of a tropical cyclone. Example imagery andnvertical radar profiles are presented. These data are currently beingnused by the authors for vertical profiling algorithms which exploit theninformation contained in both the radar and radiometer. The radar datanprovide clues to the underlying cloud vertical structure that can benused to mitigate ambiguities in profile-based retrieval algorithms thatnrely upon the passive T_B alone