南北过渡带典型流域径流变化归因对比研究

Comparative Study of Runoff Changes and Their Attribution in Typical Watersheds in China’s North-South Transitional Zone

为探明中国南北过渡带不同河川径流变化的差异,采用线性趋势回归法与累积距平法对比分析了1975—2015年南北过渡带秦岭南麓汉江源武侯站与北麓渭河源武山站的径流变化特征,采用基于Budyko水热平衡方程的弹性系数法开展径流变化的归因识别。研究发现:汉江源区径流呈微弱减少趋势,渭河源区径流呈极显著减少趋势,分别于1990年和1993年发生突变;两流域年径流量均对气候变化较为敏感,特别是汉江源区,其径流对降水变化表现出较高的敏感性;降水、潜在蒸散发和下垫面变化对汉江源径流变化的贡献率分别为65.23%、6.02%和28.75%,对渭河源径流变化的贡献率分别为24.51%、26.62%和48.87%。研究结果表明渭河源区径流对人类活动影响更加敏感。

This study attempted to identify the differences in runoff changes of two rivers in the south and north of China’s north-south transitional zone.The linear regression test and the cumulative anomaly method were applied to detect temporal variations in runoff at Wuhou and Wushan stations in the sources of Hanjiang River and Weihe River from 1975 to 2015.The elasticity coefficient method based on the Budyko hydrothermal balance equation was applied to quantify the attributions of climate change and land surface changes.The results show that the annual runoff at Wuhou in Hanjiang River shows a slightly decreasing trend,whereas runoff at Wushan Station shows a significant decreasing trend.Abrupt changes are detected in 1990 and 1993 respectively.Runoff in both watersheds shows high sensitivity to climate change,especially in the source of the Hanjiang River,its runoff shows high sensitivity to the changes of precipitation.The changes in precipitation,potential evapotranspiration and land surface contribute 65.23%,6.02%and 28.75%respectively to the runoff changes in the source of the Hanjiang River and 24.51%,26.62%and 48.87%respectively in the source of the Weihe River.Furthermore,the runoff in the source of the Weihe River is highly influenced by human activities comparing to that in the source of Hanjiang River.