| Summary: | 碩士 === 國防大學理工學院 === 大氣科學碩士班 === 98 === In this study, the observations from the precipitation radar（PR）aboard the Tropical Rainfall Measuring Mission（TRMM）satellite are used for adjusting ground-based radar calibration biases, and minimizing systematic errors associated with the differences in different radars. Furthermore, with the project we would like to promote the accurate determination of the radar rainfall estimation, and to proceed PR and ground-based radar in Taiwan area reflectivity data comparisons of statistic differences and relative magnitudes. Moreover, to compare reflectivity spatial patterns and relative magnitudes between the radars, it can be useful for the systematic monitoring of ground radar biases and studying of its effect.
The method we used in this study is according to Bolen and Chandrasekar（2003）. The data we used to intercompare are TRMM PR products and Taiwan ground-based radar.（1. Central Weather Bureau radars－WU-FEN-SHAN、HUAL-LIEN、CHI-GU、KEN-TING. 2. National Central University C-band Dual-Polarimetric radar. ） The geometric method makes use of variable resolution volume matching to minimize the effects of potential geometric distortion in space radar. In the period of 2006 to 2009, the results of comparison show that the WU-FEN-SHAN mean reflectivity are lower than PR about 1.07 dB. But the other three radars are higher than PR 1.23（HUAL-LIEN）,0.54（CHI-GU）,0.78（KEN-TING） dB respectively. From May to September in 2008, the National Central University C-band Dual-Polarimetric radar mean reflectivity are higher about 1.16 dB than PR. If adjust the biases between PR and ground-based radar in five kilometer high, the reflectivity differences between two ground-based radars will reduce about 2-5 dB, and also the differences of rain-rate will reduce about 16-27 mm/hr further.
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