摘要
本文主要內容是利用中壢特高頻雷達來研究對降水回波功率與降水粒子終端速度的的觀測結果討論與模擬。所使用的資料為2000年7月18日1544~1952 LT　的觀測資料。發現當降水回波與終端速度在同一個range gate 為負相關與正相關的頻譜寬做比較，在負相關性部分的頻譜寬會有明顯比正相關性部分的頻譜寬大的現象。另外，由觀測資料發現，融解層之上如果有較強的上升氣流產生時，其對應的回波功率也愈強，而融解層以下則是當有較強上升氣流產生的時候，其對應的回波功率則是愈小。在分析降水回波功率與終端速度間的相關性時，發現在層狀降水的部分會有正負相關性交錯的現象，針對此現象，我們針對負相關性的部分作模擬分析，發現可以模擬出符合負相關性的降水粒子分佈模型。

Abstract
In this research, we use the observation results of Chung-Li VHF radar to discuss and simulate the echo power of precipitation and terminal velocity of rain drops. According to the results, we found that if the updraft is happening in the region above (below) the melting layer, the relative echo power is larger (smaller).
After we analyzed the correlation between the echo power and the terminal velocity. We found that there exist both positive and negative correlation cases for the stratiform precipitation. In light of this phenomenon, we simulate the negative correlation cases and build up a drop-size distribution model which finely agree with the negative correlation coefficient.

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