利用二維雨滴譜儀研究雨滴譜特性

Characteristics of the Raindrop Size Distribution in Northern Taiwan from the 2-D Video Disdrometer Data Analysis

林位總(Wei-Jhong Lin) ； 陳台琦(TaiChi Chen Wang)

《大氣科學》 35卷1期 (2007/03) Pp. 69-86

摘要

雨滴粒徑分佈可以決定雲中含水量(W)、回波強度(Z)、降雨率(R)等積分降雨參數，因此分析雨滴粒徑分佈(Drop Size Distribution, DSD)的特性十分重要。本篇文章以2001及2002兩年二維雨滴譜儀資料，進行Gamma分布計算，進一步也對梅雨季（5、6月）及颱風季（7~9月）分析雨滴譜特性，結果顯示利用不同的季節，所分析之雨滴譜參數的分布有不同的特徵。另外也進行了正規分布(Normalized Gamma DSD)，的分析，有較佳的物理意義描述雨滴個數的多寡及變化。並以降雨率及回波不同等級之分類，研究雨滴譜之特性及Z-R關係式之變異性。研究中也發現，在相同的回波強度(Z)下，其最大降雨個案以及最小降雨個案在雨滴譜的特性上，有明顯的差異性存在，本文進一步針對同一降水事件分析其DSD分布特性的演變。

關鍵字

雨滴粒徑分佈 ； 雨滴譜儀 ； 降雨率

並列摘要

The Characteristics of Drop Size Distribution (DSD) is of vital importance to the calculation of radar reflectivity, rainfall rate, and liquid water content. There is also a long tradition to study the precipitation processes through the DSD analysis. In this paper the DSD data sets collected by a 2-D Video disdrometer from 2001 to 2002 were analyzed according to the different classification. The results show that there is obvious difference in DSD between Mei-Yu season and typhoon season. The normalized DSD parameters were also studied for two extreme types of DSD with the same reflectivity. The first type exhibits larger total concentration, smaller median diameter and the heaviest rainfall. As a strong contrast, the second type has less total concentration, bigger median diameter and smallest rainfall. The evolution of DSD during the whole life cycle of a precipitation system in Mei-Yu season was also illustrated.

並列關鍵字

Drop Size Distribution ； Disdrometer ； Rainfall rate