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題名 | 長生命期鋒面雨帶之研究(2):地形效應=A Study of a Long-Lived Rainband (Ⅱ): The Terrain Effect |
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作者姓名(中文) | 潘秋吟; 陳臺琦; 鄧仁星; 林沛練; |
作者姓名(外文) | Pan, Chiu-yin; Wang chen, Tai-chi; Teng, Jen-hsin; Lin, Pay-liam; |
書刊名 | 大氣科學 |
卷期 | 27:3 1999.09[民88.09] |
頁次 | 頁191-213 |
分類號 | 328.63 |
語文 | chi |
關鍵詞 | 追隨地勢坐標; 地形效應; 鋒面雨帶; Frontal rainband; Tarrain following coordinate; Terrain effect; |
中文摘要 | IOP13為TAMEX期間較為特殊的案例,其生命期長達二十幾個小時,為了要研究其緩慢移動及長生命期的特徵和在登陸後能持續發展的原因,在本文中將以登陸後多個連續時間的回波分析來探討雨帶在地形上的演變,並用追隨地勢座標雙都卜勒風場合成計算其三維風場來探討地形對內部氣流結構的影響。 由6月25日0747~1036LST的徑向風場及回波場分析,地形的作用使風切線及雨帶的走向由東北-西南走向逐漸變成風切線的北段更偏沿地形的南-北走向而其靠海的南段則偏東西走向。但值得注意的是,由不同高度回波結構分佈的分析結果來看,中低層的回波形態呈現與登陸前相似之平行風切線方向雨帶及登陸後增強之平行地形走向雨帶的兩帶狀分佈。同時垂直運動中心明顯分成兩列,一列仍與主要風切輻合帶配合,另一列則平行於南北走向之山勢。 為了探討地形對雨帶的影響,故將範圍縮小至地形處,使用追隨地勢座標來作回波和合成風場分析,以探討地形對垂直風場分佈之改變。由分析結果得知,與地形接觸後,地形的抬升作用使低層西南氣流的水氣可往上傳輸至中層,當低層的水汽供應與中層的輻合配合的當時,可增強垂直速度且回波可垂直發展的很高,造成降水系統對流區位置重新分配,氣流結構發生改變,而可進一步的解釋此對流雨帶登陸後仍能維持長生命期的原因。 |
英文摘要 | IOP#13 is a rather special case in TAMEX (Taiwan Area Mesoscale Experiment), 1987. A long-lived mesoscale convective system was riding along the shallow shear zone which was referred as Mei-Yu front. It's life period extended more than 20 hours. In order to study its slow motion and its interaction with terrain, we carry out the Dual-Doppler synthesis of eight consecutive volume scans. The terrain following coordinate system was applied to the synthesis algorithm to include the slope wind effect. From the radial wind and reflectivity pattern, 0747 to 1036 LST June 25th, indicated that the terrain will cause a second wind shear zone and rainband along the N-S mountain ridge while the original NE-SW oriented shear zone and rainband will become more E-W after it encounter the mountain area. However this new pattern still have enough moist and warm inflows from west and southwest direction. Hence the long lived system still sustain. Within the smallest synthesis domain, we can observe the SW inflow was flowing under the westly inflow at the central part of the system before landfall. But after landfall it encounter the slope of mountain ridge, it will blow up along the slope. This extra upward motion will intersect the NE-SW shear zone updraft above. Then an erected updraft will form to cause strong convection effect to enhance and sustain the rainband. The results show that the terrain following synthesis is very helpful for studying terrain effect. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。