本研究之最主要的目標是以分析總可降水量 (total precipitable water, TPW) 、海氣參數及降雨量的變化情形建立一個適用於台灣地區的乾旱分析方法，以期尋找出可能的乾旱預警指標。並針對全球、區域及單站等不同尺度來看台灣旱象降水與海氣參數的特徵。以全球尺度而言，NOAA系列衛星求得全球緯向0-30度總可降水量平均；區域尺度而言，DMSP衛星選取北緯0至40度，東經100-140度作區域性的範圍平均；單站而言，分別以板橋及花蓮探空測站為例。結果顯示：2002、2003年的總可降水量，不論其單月平均或是年平均可降水量，均較於近十二年來之長期平均值有明顯減少的現象，而在海氣參數的部分較近八年平均值，海溫在2002年底都是偏低，而2003年底偏低的情況略少，此外潛熱通量在2003年底時並無偏低的情況，而這也是說明了在2004年初的春雨並無大幅減少的可能原因。經由海氣參數與地面雨量站作相關性分析後以A區(北台灣海峽)為建置乾旱指標的研究地區，而指標的結果與下ㄧ季全台平均雨量在定性上約有70％的準確性，而在定量上的相關性約0.5。此外若以年底末季所合成的乾旱指標預報隔年的年平均雨量，在定性上預報準確性約有85％，在定量上相關性約有0.8。 The purpose of the research is to analyze the total precipitable water (TPW), rainfalls, and the sea-atmosphere parameters variations around Taiwan area, and to make a drought index for predicting the drought occurrence in Taiwan area. First, the zonal mean TPW of 0o to 30oE from NOAA satellites were analyzed to understand the global scale TPW variation, and TPW and the sea-atmosphere parameters within the area covered 0 to 40N and 100 to 140E measured by the Defense Meteorological Satellite Program (DMSP) satellites were analyzed to see the local scale variation. Radiosonde data collected at Panchiao and Hualian stations in Taiwan were also used to compare the previous two sets of satellite observations for validation. The result shows that TPW of 2002 and 2003 had the lowest values during the past 12 years. In addition, the latent heat flux and sea surface temperature of 2002 had the lowest values during the recent 8 years. In the end of 2003, the result also shows that the latent heat flux was normal and the sea surface temperature slightly below normal. That is the reason why the spring rain still maintain normal in the early months of 2004. By the correlation analyzing, the North Taiwan Strait test area was pickup, and the sea-atmospheric parameters in this area were used to make a drought index for the whole Taiwan area. The test result shows that the drought index made in this study could work well.
