華南春季低層噴流之形成與台灣北部地區豪雨之個案分析

A Case Study of the Formation of a Low Level Jet over Subtropical China an Heavy Precipitation in Northern Taiwan

陳泰然(George Tai-Jen Chen) ； 蒲金標(Chin-Piao Pu)

《大氣科學》 12卷1期 (1985/03) Pp. 23-32

摘要

本文針對1983年3月12日於台灣北部發生先連續性後間歇性之大量降水與雷雨之不尋常現象，利用傳統及衛星資料進行分析研究。結果發現850 mb高壓迅速向東南移動，使華南產生高度梯度之增強，為低層噴流形成之主要機制，中尺度對流複合系統則在低層噴流下游速度輻合區與風場輻合隨時間增加區發展及維持。850 mb槽前平行於槽之準線性中尺度對流系統，顯係由低對流層正渦度平流向上增加之準地轉動力強迫作用所激發。最後發現，台灣低壓可在缺乏500 mb正渦度平流及海面可感熱加熱微弱之情況下，透過MCC之潛熱加熱過程形成並加強。

並列摘要

A case of continuous heavy rainfall and severe thunderstorms followed by intermittent convective activities on March 12, 1983, a rather unusual phenomenon in Spring, was selected in this study. It was found that a low level jet at 850 mb was developed over southern China in response to the fast movement of a high pressure system southeastward to subtropical latitudes. MCC'S tended to develop and be maintained over the area downstream of a low level jet and over the area o f increased convergence. A quasi-linear mesoscale convective system appeared to develop ahead of 850 mb trough due to the quasi-geostrophic dynamic forcing in the lower troposphere. Finally, it was found that in the absence of 500 mb positive vorticity advection and sea surface sensible heat transport; Taiwan low can develop by convective heating process of a MCC system.