臺灣博碩士論文加值系統

本研究利用空軍馬公雙偏極化雷達及中央氣象局七股都卜勒雷達進行雙都卜勒雷達資料合成，於凡那比(2010)颱風中心自台灣南部陸地出海前、其西南側雨帶明顯增強之際，針對該雨帶進行觀察與分析，並推測其隨後引發颱風眼牆重建之原因。
由雙都卜勒雷達合成之風場資訊顯示，在該雨帶內緣(靠近颱風中心一側)之底層存在明顯輻合，中高層以上轉趨輻散之現象；透過垂直剖面圖可以發現，雨帶底層存在自海面流向颱風中心之徑向內流，且20~30dBZ 以上之回波發展高度普遍可達10~15 公里高度，而在8~10 公里高度位置存在可能是由於冰晶形成過程產生之大量潛熱釋放所造成，垂直運動速度達每秒10 公尺以上之上升運動區；此外，透過分析渦度收支方程式各項因子可以發現，水平平流項對渦度趨勢之影響最鉅，輻散項在底層的正貢獻隨時間有明顯增加之趨勢，傾斜項則是除了水平平流項外，在中高層扮演了最重要的角色。
以上各種特徵顯示該雨帶中極可能有渦旋熱塔(Vortical Hot Tower)的存在，透過升尺度(Upscale)作用使得同時間颱風中心氣壓持續下降，進而增強沿雨帶方向旋轉之逆時針環流，最終引發眼牆的重建。

By synthesizing the respective dual-polarimetric and Doppler radar data from Ma-Kung and Chi-Gu, this study seeks to analyze the relevant mechanisms behind the intensification of the rainband in the south-west quadrant of Typhoon Fanapi(2010). In addition, this study also offers insights as to why the typhoon eyewall was able to build again, when the typhoon center was about to leave the Taiwan area.
Analysis of the dual-Doppler radar data shows the presence of convergence zones and divergence zones located respectively in the lower and middle to upper levels of the inner rainband region(side close to the typhoon center). From the typhoon’s vertical profile, we discover a strong inflow into the typhoon center from the outer sea surface near the bottom of the typhoon, and reflectivity at the 20~30dBZ range increased to the 10~15 kilometer level. An updraft region exceeding 10 meters
per second was observed at a height between 8~10 kilometers. This was likely caused by the high latent heat released from the formation of ice crystals. Furthermore, we found that the horizontal advection term contributed the most to the vorticity tendency, based on the analysis of the vorticity budget equation. In the lower atmosphere, the positive contribution of the divergence term increased evidently with time, and the tilting term played the most prominent role in the middle to upper atmosphere, excluding the horizontal term.
The aforementioned features indicate the possible existence of a vortical hot tower within the rainband. A subsequent upscale process thus developed, which resulted in the typhoon center pressure to drop continuously, and the counterclockwise circulation along the rainband to accelerate. This eventually led to the reconstruction of the typhoon eyewall.

誌謝 ii
摘要 iii
ABSTRACT iv
目錄 v
表目錄 vii
圖目錄 viii
1. 前言 1
1.1 研究動機 1
1.2 文獻回顧 1
1.3 研究的 5
2. 資料與方法 6
2.1 資料來源 6
2.1.1 馬公雙偏極化雷達 6
2.1.2 七股都卜勒雷達 6
2.2 雙偏極化雷達參數介紹 6
2.2.1 反射率(Reflectivity；ZHH、ZVV) 6
2.2.2 差異反射率(Dfferential Reflectivity；ZDR) 7
2.3 雷達參數誤差修正 8
2.4 執行雙都卜勒雷達合成前資料完整性之確認 9
2.5 雙都卜勒雷達資料合成 9
3. 結果與討論 11
3.1 環境場及颱風結構演變之分析 11
3.2 降雨演變趨勢及特徵分析 14
3.3 馬公雷達回波資料分析 15
3.4 雙都卜勒雷達資料分析 15
3.5 渦度場及渦度收支各項之特徵分析 18
3.5.1 渦度場特徵分析 18
3.5.2 「渦度趨勢」與「渦度隨時間變化」之比較及特徵分析 19
3.5.3 渦度收支方程式中各項因子變化特徵分析 22
3.5.3.1 渦度趨勢項變化特徵分析 23
3.5.3.2 輻散項變化特徵分析 23
3.5.3.3 傾斜項變化特徵分析 25
3.5.3.4 水平平流項變化特徵分析 26
3.5.3.5 垂直平流項變化特徵分析 26
3.5.3.6 渦度收支各項於正渦度相對極大值區域內之面積平均特徵初步分析 27
3.6 雨帶增強期間颱風中心氣壓趨勢分析 28
3.7 雨帶增強期間紅外線色調強化彩色雲圖及可見光雲圖分析 29
4. 結論 31
參考文獻 88
論文發表 90
自傳 91

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