台灣梅雨期豪雨之時空分布特徵

On the Spatial and Temporal Patterns of Heavy Rainfall in Taiwan Mei-Yu Season

陳泰然(George Tai-Jen Chen) ； 楊進賢(Jinn-Shang Yang)

《大氣科學》 16卷2期 (1988/06) Pp. 151-162

摘要

本文分析1975～1984年5～6月台灣地區各測站非颱風型豪雨之特徵，將台灣地區分成北、中、南、高山、盆地與島嶼等七種不同類型，分析其間豪雨時空分佈特性之異同。豪雨起止時刻與最大時雨量出現時間、生命期、豪雨降水量之日夜變化與豪雨個案降水量時間合成分佈等均經分析。結果顯示，地形效應為導致地區豪雨發生之重要因子，而中尺度低壓與豪雨有密切關連。局部環流與大氣不穩定度之改變，似為決定豪雨日夜變化之主要因子。此外，發現豪雨特徵顯現之中尺度對流系統，其最強對流中心之數目與強度密切關連，數目多則強度弱，而中尺度對流系統範圍較大者之平均強度亦較弱。

關鍵字

豪雨 ； 中尺度對流系統 ； 日夜變化 ； 地形效應

並列摘要

Rainfall data in May-June 1975-1984 were analyzed to study the characteristics of non-typhoon associated heavy rainfall in the Mei-Yu season. The spatial distribution and temporal patterns in 7 different geographical areas were studied. These areas include northern Taiwan, central Taiwan, southern Taiwan, eastern Taiwan, mountain area, basin area and island stations. The starting time and the time of maximum hourly rainfall were analyzed. The duration and diurnal intensity variation of heavy rainfall were presented. The composite curves of rainfall intensity and frequency were generated for the single-, double- and triple-peak heavy rainfall events.Results showed that the topographical effect is an important factor in producing heavy rainfall. It was also observed that the mesolow and the heavy rainfall are closely related. Diurnal variations of heavy rainfall were found to be mainly modulated by the local circulations and the stability changes. Furthermore, the characteristics of heavy rainfall revealed the possible structure of the mesoscale convective systems (MCSs). The intensity of the convection seems to beclosely related to the number of the convective centers within in the MCS. The single-center MCS is stronger than the double-center one, and the double-center MCS is stronger than the triple-center one. Finally, the MCS with a greater horizontal scale has a weaker mean intensity.

並列關鍵字

heavy rainfall ； MCS ； diurnal variation ； orographic effect