應用趨勢分析探討氣候變遷下太麻里溪流域的水文變化

Application of Trend Analysis to Explore Hydrological Change under Climate Change in the Taimali Stream Basin

受到氣候變遷與極端氣象事件所影響，近年來臺灣地區的降雨量變化趨勢有顯著的改變。河川流域內之水文條件與氣候息息相關，為了探討氣候變遷對於水文條件之影響，本研究應用M-K趨勢檢定及 Theil-Sen 斜率檢定，探討太麻里溪流域內 1981 年至 2012 年之降雨量、1983 年 8 月至 2009 年 7 月之逕流量及 1984 年至 2008 年之輸砂量的變化趨勢。研究結果顯示，年降雨量、秋季降雨量、豐水期降雨量以及八月降雨量皆呈現顯著增加之趨勢，其 τ 值分別為：0.29、0.25、0.27以及 0.23；年逕流量及秋季逕流量亦呈現顯著增加，其 τ 值分別為：0.27 與 0.24；此外，年輸砂量、秋季輸砂量以及豐水期輸砂量也呈現顯著增加，其 τ 值分別為：0.28、0.25 與 0.25。透過趨勢檢定可以發現，氣候變遷對於太麻里溪流域之水文變化具有相當影響力，造成年降雨量、年逕流量與年輸砂量皆呈現顯著增加趨勢，尤其是集中於秋季及豐水期期間，增加趨勢更是明顯。 Due to the climate change and the extreme weather events, the precipitation in Taiwan has changed very dramatically. The hydrological conditions in a basin are highly related to the weather. In order to identify the effect of the climate change, we assess annual, seasonal and monthly trends of precipitation from 1981 to 2012, stream runoff from August in 1983 to July in 2009, and sediment load from 1984 to 2008 in the Taimali stream basin using the Mann-Kendall trend test and the Theil-Sen slope test. The results show that the precipitations of annual, wet period, autumn season, and in August have significant increasing trends. The τ values are 0.29, 0.27, 0.25, and 0.23, respectively. The stream runoffs of annual and autumn season also have significant increasing trends. The τ values are 0.27 and 0.24, respectively. In addition, the sediment loads of annual, wet period, and autumn season also have significant increasing trends. The τ values are 0.27, 0.25, and 0.25, respectively. Through the trend analysis, we can identify that the hydrological conditions in the Taimali stream basin are strongly affected by the climate change. It causes the annual precipitation, stream runoff, and sediment load significantly increasing, especially for the autumn season and wet period with obvious increasing trend.

Due to the climate change and the extreme weather events, the precipitation in Taiwan has changed very dramatically. The hydrological conditions in a basin are highly related to the weather. In order to identify the effect of the climate change, we assess annual, seasonal and monthly trends of precipitation from 1981 to 2012, stream runoff from August in 1983 to July in 2009, and sediment load from 1984 to 2008 in the Taimali stream basin using the Mann-Kendall trend test and the Theil-Sen slope test. The results show that the precipitations of annual, wet period, autumn season, and in August have significant increasing trends. The τ values are 0.29, 0.27, 0.25, and 0.23, respectively. The stream runoffs of annual and autumn season also have significant increasing trends. The τ values are 0.27 and 0.24, respectively. In addition, the sediment loads of annual, wet period, and autumn season also have significant increasing trends. The τ values are 0.27, 0.25, and 0.25, respectively. Through the trend analysis, we can identify that the hydrological conditions in the Taimali stream basin are strongly affected by the climate change. It causes the annual precipitation, stream runoff, and sediment load significantly increasing, especially for the autumn season and wet period with obvious increasing trend.