潭美颱風高雄豪雨事件之天氣分析

Weather Analysis of Violent Rainfall Event in Kaohsiung Area by Tropical Storm Trami(2001)

謝信良(Shinn-Liang Shieh) ； 簡國基(Guo-Ji Jian) ； 王時鼎(Shih-Ting Wang)

《大氣科學》 31卷1期 (2003/03) Pp. 1-15

摘要

本文利用都卜勒雷達、衛星及地面觀測資料，描述2001年潭美(Trami)颱風之侵台過程，內容則著重在天氣分析與現象說明。潭美是小型且微弱的輕度颱風，生命史僅36小時；歸納其所造成之豪雨，共可分為三階段，階段一為颱風環流豪雨，發生在7月11日上午的蘭嶼地區；階段二是低層環流減弱，西南氣流增強之豪雨，出現於11日下午之屏東及高雄山區。第三階段颱風雖已減弱為熱帶性低氣壓，但內部伴隨中尺度渦旋發展，引發比前兩階段更為劇烈的豪雨，發生於11日夜間之大高雄地區；其中高雄氣象站11日總雨量並創下40年來之最大日降雨量（470.5公厘）紀錄，當日雨量的89%均集中於10Z～16Z之間降下，可見此階段降雨之急劇。
雷達及地面觀測資料顯示，伴隨第三階段豪雨的中尺度渦旋，係於11日上半夜（約11Z起）在大高雄地區組織發展，成熟後則緩慢向北運動，劇烈降雨區也因而逐漸向北擴展；中尺度渦旋中心繼而通過台南站東側，最後於16Z～17Z左右自台南站北側出海，南台灣雨勢才逐漸緩和。潭美颱風運動軌跡之天氣分析顯示，颱風環流於接近台灣地形時，很可能出現高、低層環流分離現象；其中，低層環流減弱消失於台灣東南方近海，高層環流中心則持續向西北運動，以連續路徑通過台灣地形。

關鍵字

潭美颱風 ； 颱風豪雨 ； 中尺度渦旋

並列摘要

This article uses Doppler radar、satellite and surface observational data, on the weather analysis point of view, describing the weather phenomenon during tropical storm Trami(2001)passed through Taiwan. Trami was a small and weak tropical storm in its 36 hours lifetime. For the heavy rainfall induced by Trami, it could be divided into three stages. The first stage produced by Trami's circulation and occurred at Lanyu in the morning of 11 July. The second stage caused by the intensification of southwest flow as Trami's low level circulation was weakened, heavy rainfall appeared in Pington and Kaohsiung's mountain area in the afternoon of 11 July. The third was the most violent rainfall stage, though Trami had weakened into a tropical depression, due to the formation and development of a mesovortex in it. Such devastating rains occurred in Kaohsiung area at night of 11 July, and resulted in record-breaking daily precipitation at Kaohsiung station(up to 470.5mm)in recent forty years. One noticeable thing was more than 89% rainfall concentrated between 10UTC and 16UTC 11 July, that perceived hasty and fierce character in this stage. Doppler radar and surface observational data showed that the mesovortex, which produced devastating rains in stage three, organized and developed in Kaohsiung area time before midnight of 11 July. It moved northward slowly then, the accompanying heavy rainfall area extended northward also. After that, the mesovortex passed eastside of Tainan station and entered Taiwan strait from north of Tainan between16UTC and 17UTC.The precipitation eased at last. As for the track, on the weather analysis point of view here, Trami's circulation possibly appeared vertical decouple as it approached Taiwan. Its low level circulation weakened and vanished in southeast coastal waters of Taiwan, but the high level circulation moved toward northwest with continuous track passing through Taiwan topography.

並列關鍵字

Tropical storm Trami ； Heavy rainfall ； Mesovortex