本文利用中央氣象局高雄WSR-64M(1984及以前年份)與WSR-81S(1986年起)氣象雷達1981-1990(缺1985)共九年五月及六月份,層狀降水回波面積在5000平方公里以上,且觀測範圍內至少有一氣象測站日降水量≧50mm,觀測員根據PPI顯示之描繪圖(CV圖),包括降水回波形狀、排列與移動狀況、時空變化,以及由發展、成熟到消散之演變,做詳細分析,以統計臺灣西南部強降水雷達回波之氣候特徵。結果共選出個案101個。綜合而言,這些個案的回波形狀以長條(佔40.6%)與塊狀(佔35.6%)為主,且多(63.4%)以≧6m/s的速度向東或東北(71.3%)移動。其它重要特徵尚包括(1)層狀降水回波面積在10000平方公里者約佔80%,但中間的對流降水回波70%在1000平方公里或以下。(2)達豪雨標準(日降水量≧130mm)之個案共26個,其中條狀與塊狀分別有13及11次,另兩次則為散狀。(3)平均而言,豪大雨回波之總生鉻期約為11個半小時,發展與成熟期約各佔四個小時,另約三個小時為消散期。(4)整體而言,回波發展多在午夜至1500LST時段,成熟期多在0300-1800LST間,其中以1200-1400LST者為最多,至於消散期則多發生於0900-1200LST間與1500LST以後。(5)在與綜觀環境配合方面,豪大雨個案中長條與塊狀兩類回波在鋒前、鋒區、鋒後者約各佔37.5%,58.3%與4.2%。62.5%個案發生時850hpa有大於20krs的低層噴流LLJ,100%個案生時700hpa有大於20krs的LLJ。其次,91.6%個案回波發生在500hpa槽前。(6)探空分析顯示,豪雨時風隨高度順轉,總指數(T)與K指數平均值分別為44與36。
By using the 1981-1990(1985 missing) isoecho contouring analysis of a WSR-64M (before 1984) and a WSR-81S) since 1986) weather radar which located in Kaoshang, south south-west of Taiwan heavy (≧50mm/day) and torrential (130mm≧mm/day rainfall event was studied. A radar climatology and a composite synoptic weather chart are presented in this paper. In there, 101 cases were identified and, in accordance with, their pattern, movement, lifetime, and time sequence, four characteristics were categoried. Synoptic and static stability conditions are also summarized.