本研究利用Mann-Kendall法檢視台灣地區1961-2008年間中央氣象局地面觀測站的地表風速之長期變化趨勢。研究結果顯示：無論都會區或非都會區，1974年之後，大多數測站全年平均風速及冬季季風風速皆有明顯地變小趨勢。因為都市化效應(Urbanization)的緣故，都會區的風速遞減趨勢大於非都會區的遞減趨勢，且無都市化效應的離島地區(蘭嶼、彭佳嶼和東吉島)全年及冬季的強風發生機率亦有逐年下降的趨勢。本研究亦針對颱風侵台期間的地表風速加以分析，結果發現颱風侵台期間的最大風速及全台平均風速皆呈現遞減的長期變化趨勢。本研究並計算百分位數(percentile)的風速趨勢，發現大多數地區的10th、25th、50th、75th、90th風速的百分位數呈現下降的趨勢。高風速下降率尤其特別明顯。此下降趨勢都與其他國家風速變化趨勢的結果相似。 除此之外，本研究並利用台灣地區的風速資料分析風力發電的變化趨勢，本研究採用兩種不同的方式估算風力發電量，第一種方式依據地面實測風速1961~2008年的歷史資料與風機的性能曲線計算風力發電量，第二種方式依據韋伯機率函數與風機的性能曲線積分求得風力發電量。本研究計算未受到都市化影響的測站：東吉島、蘭嶼與梧棲的風能潛勢，再分析澎湖中屯風力發電廠2002~2009年的實測風力發電量，研究結果發現兩種方式計算得之風力發電量的下降趨勢，東吉島的下降率為-2.25% decade-1，蘭嶼為-8.06% decade-1，梧棲為-26.98% decade-1。離島地區的下降趨勢小於海岸地區的下降趨勢。This study used the Mann-Kandall test to check to long term trend of surface wind speeds in Taiwan during the period of 1961-2008. It was found that the annual mean wind speeds of most stations after 1974 have a decreasing trend. But the decrease rate of urbanized area 0.155 m s-1decade-1 (-6.18 % decade-1) is larger than that of rural area 0.135 m s-1 decade-1 (-3.14 % decade-1). The mean wind speeds of winter months (November – February) also demonstrate a negative trend in most meteorological stations. In addition, the maximum wind speeds and average wind speeds during the typhoon-invaded periods all show a steady decline. Then the long term trend of wind power potential in Taiwan was analyzed. The wind power potentials of three stations: Dong-Ji Islet, Lan-Yu Islet and Wu-Chi were calculated by using the two-parameter Weibull probability function and the performance curve on a wind turbine. The parameters in Weibull function were determined by method of moment from the hourly wind speed data between 1961~2008. The results indicate that the wind power potential also show declining trend for all three stations, the decrease rate are around -2.25% decade-1 in Dong-Ji Islet, -8.06% decade-1 in Lan-Yu Islet and -26.98% decade-1 in Wu-Chi, respectively. The decreasing rate of the island and off-shore is less than of the coastal area.
