蘇門答臘島為中心位置位於赤道，呈西北-東南走向的一個狹長島嶼，其山脈亦呈西北-東南走向，綿延1600公里，最高海拔達3800公尺。北半球冬季期間，亞洲冬季季風常可延伸至海洋大陸區域，當東北風受到蘇門答臘狹長且高聳的山脈地形阻擋，易在蘇門答臘西側兩端背風處形成背風渦漩(Lee Vortex)。由於蘇門答臘地形的獨特性，南北兩端之背風渦漩恰為氣旋式之環流，本研究將以蘇門答臘背風渦漩是否能發展為熱帶氣旋為重點，探討蘇門答臘地形對印度洋熱帶氣旋生成的影響。
由於東北風較不易跨越赤道南下至蘇門答臘南端，故本研究選取YOTC (Year of Tropical Convection)期間(2008 - 2010)，所有蘇門答臘北端西側之背風渦漩發展為熱帶氣旋之4個個案進行分析，並選擇2個強度較強的個案進行數值模擬。其中一個個案位於蘇門答臘南端西側亦有熱帶氣旋生成，本研究亦會探討蘇門答臘地形對其生成的影響。本研究使用的模式為雲解析風暴模式(CReSS)，在完成控制組的模擬以及校驗後，並進行了無地形組的敏感度實驗。
渦旋之渦度垂直剖面時序顯示，在渦漩仍處背風處時，控制組中渦漩低層的渦度較大，且低層的渦度收支診斷結果顯示，該期間控制組之渦漩有較大的輻合項，顯示蘇門答臘的地形效應確實使渦漩在背風區域時有較大的渦度，此原因為東北風受地形阻擋而形成角隅流(Corner Flow)，使渦旋北端有較強的風速，以及更封閉的環流結構。
由選取個案之綜觀分析來看，自南海向西移動的熱帶氣殘留系統、熱帶擾動或其他對流系統所提供的正渦度以及水氣的平流效應亦是相當重要的熱帶氣旋生成因素之一，當上述系統受東北風向西平流進入到北印度洋後，能夠提供背風渦漩正渦度以及水氣平流，使背風渦漩有更好的發展環境。從控制組以及無地形組的模擬結果來看，地形效應雖能增強背風處渦漩的中低層渦度，但並不是使選取之個案發展為熱帶氣旋的關鍵要素，其生成原因為東北風或是東風和赤道西風所提供的風切環境以及上述來自南海的正渦度以及水氣平流。
另外從控制組和無地形組的比較顯示出當赤道西風到達蘇門答臘時，西風受蘇門答臘高聳的地形影響會偏折為西北風，若有低壓位於蘇門答臘南端的近海，此偏折之西北風能使低壓東側的環流更為閉合，控制組低壓之中低層有較強的平均渦度以及輻合項，使低壓有較好的結構以及能較快的發展為熱帶氣旋。

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