臺灣地區區域降雨總量及極端降雨與乾旱之變遷特性

Regional Changing Patterns of Total Rainfall, Extreme Rainfall and Drought in Taiwan

王婕妤(Chieh-Yu Wang)

指導教授 ： 吳瑞賢

國立中央大學/工學院/土木工程學系/碩士(2012年)

摘要

近年，臺灣受到氣候變遷的影響，出現降雨分布集中、降雨強度越來越大的趨勢，使得臺灣未來很可能面臨水旱災頻率增多、水庫蓄水量不足等情況，造成水資源的調度與分配更加困難。本研究以1990為分界，透過資料分析，探討1990年前和1990年後，氣候變遷對臺灣地區旱、澇之影響，並對歷年降雨量進行趨勢分析及比較。
首先，本研究分析50年之長期雨量站資料，探討是否存在明顯之趨勢變化，並進一步計算降雨總量的改變以及降雨型態是否產生空間上之變化。接著，以頻率分析計算各雨量站1961至1990年以及1991至2010年之年單日最大降雨量和年最大連續不降雨日數，探討在氣候變遷影響下極端降雨及乾旱特性之變化。
研究結果顯示，乾濕交替的月份趨勢變化比較明顯，在1991至2010年期間，中、南部地區年降雨量有上升之趨勢。經由克利金法計算高程平均年降雨量及平均總水量，發現北部地區的降雨型態已產生空間上之變化，平均年降雨量與平均年總水量在海拔200公尺至海拔1000公尺呈現減少，海拔1000公尺以上則呈現增加。而中、南部地區，雖發生極端降雨，但水庫標高以上的平均年降雨量與平均總水量均呈現增加。接著，由頻率分析發現，在氣候變遷的影響下，中、南部地區之降雨強度已增強，且氣候變遷造成的極端型降雨，已明顯對原有的重現期距分析結果造成改變。乾旱分析結果，臺灣西部地區在1991至2010年發生小旱及大旱的範圍有向內陸擴散之跡象，且中、南部沿海地區在此時期發生大旱的機率為0.02，北部則屬不易發生乾旱之地區。

關鍵字

乾旱 ； 頻率分析 ； 趨勢檢定 ； 降雨 ； 氣候變遷

並列摘要

In the recent years, the rainfall intensity rises sharply in Taiwan due to global climate variations, and it may result in the situations such as increased flooding and droughts, the reservoir storage volume is insufficient, and it causes the management and the distribution of water resources more and more difficult in the future. This study discussed the influence of floods and drought under climate change, and analyzed rainfall by the Mann-Kendall method for the trends in year 1961-1990 and that in 1991-2010.
First, this study analyzed 50 years long-term rainfall data to discuss the change of trend, and to calculate the total rainfall and the rainfall patterns in spatial. Second, this study analyzed the return period of the single day maximum rainfall and the maximum continuance days without rainfall by frequency analysis in year 1961-1990 and 1991-2010. Last, this study discussed the effect of the extreme rainfall and the drought under climate change in Taiwan.
According to the analysis result of Mann-Kendall method, there was an obvious trend appeared in the alternate drying and wetting month. The average annual rainfall showed an increasing trend in both central and southern Taiwan. Analyzing average annual rainfall and average amount of water by the Kriging method, the rainfall patterns had changed in spatial in northern Taiwan. The average annual rainfall decreased between the elevation of 200 meter above sea and that of 1000 meter above sea, and the average annual rainfall increased for the elevation above 1000 meter. In central and southern Taiwan, the average annual rainfall increased for region above the elevation of reservoir sites. In addition, the frequency analysis result showed that the rainfall intensity increased sharply in the central and south area under climate change. Extreme rainfall had changed the return period, i.e., more sever rainfall is expected in 1991-2010 than that in 1961-1990. In Central and Southern Taiwan, the range of small-scale and large-scale drought would spread gradually to inland in 1991-2010. During this period, the probability of large-scale drought occurring is 0.02 in the central and south area along the coast, while the probability is less than 0.01 in Northern Taiwan.

並列關鍵字

Drought ； Frequency analysis ； Trend test ； Climate change ； Rainfall

參考文獻

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