- 作者: 陳泰然
- 作者服務機構: 國立臺灣大學大氣科學系
- 中文摘要: 本文係針對民國六十四年六月十日至十五日間臺灣地區之梅雨個案,進行其水氣參數及降水系統之分析研究。結果顯示在臺灣海峽上空原已存在之降水系統雷達回波具有週期17小時及波長300公里之特性。這些系統有沿著850-500毫巴平均風偏右25度方向移動之趨勢。當他們移至臺灣上空時,地形效應和溫度日夜變化之熱效應,顯然對決定臺灣地區之降水強度及空間分佈佔有非常重要的角色。結果使得臺灣北部中幅度對流降水系統具有為時2.6,3.5和7.1小時之週期。 研究結果又顯示低層西南氣流,特別是低層噴射氣流,有在梅雨鋒面南部形成潛在不穩定度的趨勢。而大幅度之連續上升氣流隨即透過對流運動系統來釋放已存的潛在不穩定度。對流運動則產生雷達回波和強烈之降水。
- 英文摘要: Moisture parameters and precipitation patterns are analyzed for a synoptic case of Mei-Yuin Taiwan during the period of June 10 through 15, 1975. The pre-existing rainfall systems asevidenced by radar echoes propagate southeastward with a wave period of 17 h and wavelengthapproximately 300 km over the Taiwan Strait. These systems tend to move toward right of themean wind in 850-500 mb layer with an averaging deviation of 25°. As they move over theTaiwan Island, the local orographic effect and diuranl thermal control evidently play an im-portant role in regulating both their intensities and spatial distributions. As a result, the me-soscale convective rainfalls have the peak time periods of 2.6, 3.5, and 7.1 h in northern Taiwan. Results show that the low level southwesterlies, especially the Low Level Jet, tend to creatpotential instability to the warm side of Mei-Yu Front. Continued large scale ascents then leadto the release of potential instability through organized mesoscale convective systems. The con-vection that is released produces the radar echoes and the cells of heavy precipitation.
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