- 學位論文
西北太平洋颱風水氣與大氣溫度的關係
The Relation between Water Vapor in Typhoon and Atmospheric Temperature over Western North Pacific
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摘要
本研究以ERA-interim資料，欲探討1979-2009年西北太平洋地區，大氣溫度增加對颱風水氣的影響。利用迴歸分析和趨勢分析的方法，並以颱風水氣輻合作為中介點的角度，研究各尺度大氣溫度和各強度颱風總水氣量的關係。 從各尺度的迴歸分析發現，大尺度的大氣溫度和弱颱水氣的相關較佳，強颱則較差，利用年際差值的迴歸分析得知，西北太平洋六到十月平均的熱帶大氣溫度每上升一度，弱颱的極端水氣(水氣值的最高10 %)將增加7 %，以NCEP- CFSR資料可以得到相似的弱颱結果，但此研究於中颱、強颱並沒有顯著的相關。 年際變化的結果亦發現，西北太平洋平均大氣溫度上升，對弱颱外圍水氣增加較明顯，而且高水氣的弱颱對外圍水氣的反應比強颱明顯，故推論大尺度大氣溫度增加，將提供弱颱良好的水氣輻合環境，使最需環境支持的弱颱水氣增加。 31年趨勢分析發現，弱颱的高水氣有增加的趨勢，強颱的低水氣則有減少的趨勢，而兩者各自與其水氣輻合的趨勢相同，相關良好，並且和水氣增加率年代際變化的結果相呼應 (弱颱的水氣增加率變高，強颱則變低)。而趨勢上弱颱的低層輻合有增強趨勢，強颱則因為外圍水氣減少的趨勢，但只有強颱水氣和外圍水氣有高相關。 利用MRI-AGCM的模式資料，比較本世紀末和現在的差距，結果發現未來中颱、強颱於低水氣值時，水氣增加率將會提高，代表模式預估中颱、強颱的水氣會大幅提升，水氣值低的狀況不再。
並列摘要
Data from ERA-interim (ECMWF) covering the period June-October in 1979-2009 are examined for the relation between total column water vapor in typhoons and column mean of temperature over western North Pacific. Moreover, we take water vapor convergence as in-between to analyse the relation above. We find that water vapor in weak typhoons correlates with large scale temperature but water vapor in strong typhoons does not. The interannual results of regression analyses show that the top 10 % bin of water vapor in weak typhoons increases 7 % for each degree increase in atmospheric temperature over WNP. Furthermore, the water vapor in weak typhoons increases by environmental water vapor, which also increases by temperature over WNP. From 31-year trend analyses, the yearly means of water vapor in wreak typhoons are increasing, but water vapor in strong typhoons are decreasing. They correspond to the trends of water vapor convergence and the interdecadal changes of water vapor increase rate. Nevertheless, we find that the trend of water vapor in weak typhoons increases with convergence in 850 hPa; the trend of water vapor in strong typhoons decreases with environmental water vapor. From MRI-AGCM (JMA) data, the results of interannual differences show that the lower parts of water vapor in strong typhoons will increase in the end of this century. At last, we discuss the differences from interannual and trend results in order to clarify how temperature affects water vapor in typhoons.
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