臺灣中部流域乾旱特徵之時空變化

Spatiotemporal Variation of the Drought Characteristics in Central Taiwan

許心藜(Hsin-Li Hsu) ； 葉信富(Hsin-Fu Yeh)

《作物、環境與生物資訊》 15卷1期 (2018/03) Pp. 1-14

https://doi.org/10.30061/CEB.201803_15(1).0001

摘要

近年來受到極端氣候的影響，臺灣面臨嚴重的缺水危機，且因降雨模式的改變，使得乾旱現象愈趨明顯，影響水資源的管理及利用。因此，本研究以臺灣中部流域作為研究區域，選定13個雨量站及17個地下水位站之長期紀錄資料，利用標準化降雨量指標(Standardized Precipitation Index, SPI)及標準化地下水位指標(Standardized Groundwater level Index, SGI)分析該區域之乾旱特性。本研究分析臺灣中部流域之雨量及地下水位資料，結果顯示在2015年為嚴重乾旱年，且在SPI及SGI訊號有著一定的相關性。另外，在地下水乾旱方面，大安溪流域面臨較多次的乾旱事件，但延時及強度較低，烏溪流域則相反。最後，本研究進行SPI與SGI之交互相關性分析，其最大交互相關係數值介於0.83到0.91之間，在不同流域地下水乾旱(SGI)對應於氣象乾旱(SPI)之關係不盡相同，但皆存在一定的相關程度，其中，大甲溪流域顯示出高達0.91之最大相關性。由研究成果發現當乾旱延時較長，其強度相對較高，且在嚴重乾旱方面，因降雨造成乾旱發生頻率較地下水大。

關鍵字

標準化降雨量指標 ； 標準化地下水位指標 ； 乾旱 ； 臺灣中部

並列摘要

In recent years, Taiwan has been facing severe water shortage because of extreme weather. In addition, changes in rainfall patterns resulted in an increasingly notable drought phenomenon, which affects the management and utilization of water resources. Therefore, the basins in Central Taiwan were used as study sites in this study. Long-term records from 13 rainfall and 17 groundwater stations were selected. The Standardized Precipitation Index (SPI) and Standardized Groundwater Level Index (SGI) were used to analyze the drought characteristics of this region. The rainfall and groundwater level data from basins in Central Taiwan were analyzed in this study. The results show that the year 2015 was a year with severe drought and has some correlation with SPI and SGI signals. In addition, with regards to groundwater drought, more drought events occurred in the Da'an River basin, but the drought duration and intensity were relatively low, in contrast to that in the Wu River basin. Finally, the correlation between SPI and SGI was analyzed in this study. The greatest cross-correlation coefficient between the SPI and SGI range from 0.83 to 0.91. The correlation between SPI and SGI varies in different basins, but a certain degree of correlation was observed in all basins. Among three basins, Dajia River basin shows the maximum correlation up to 0.91. The results show that the drought intensity is relatively higher when the drought duration is longer. With regards to severe droughts, droughts caused by rainfall occur at a higher frequency than those caused by groundwater.

並列關鍵字

Standardized precipitation index ； Standardized groundwater level index ； Drought ； Central Taiwan