气候变化对汉江上游径流的影响

根据汉江上游安康以上流域1961-2005年历年逐月气温和降水量资料，统计分析了近45 a流域气候变化的基本特点。同时，通过对各站气温、降水量与安康站径流量的相关计算，建立了天然径流量气候模型，并分析了径流量对气候变化响应的敏感性。结果表明：1) 近45 a来汉江上游安康以上流域的年平均气温呈上升趋势；降水量呈递减趋势，90年代以后减少更为显著。2) 在过去45 a中，汉江上游径流量总体呈下降趋势；1961年以来，汉江上游径流量大体经历了两个丰水段和两个枯水段；1985年发生跃变，以前呈微弱的上升趋势，以后呈下降趋势。3) 径流量与区域年平均气温呈负相关，而与年降水量呈较显著的正相关，年径流量对降水变化的响应较其对气温变化的响应更为敏感。

Effects of Climate Change on Runoff Volume in the Upper Reaches of the Hanjiang River

Based on the monthly temperature and precipitation data at 14 weather stations from 1961 to 2005, the climate change characteristics in the upper reaches of the Hanjiang River upstream of Ankang in the past 45 years were analyzed. The correlation between the temperature and precipitation at each meteorological station and the annual natural runoff volume at Ankang hydrological station were calculated. After selecting the representative stations, we developed the climatic model for calculating the annual natural runoff volume, and analyzed the sensitivity of natural runoff volume to climate change and the effect of climate change on the runoff volume. The results show that the annual natural runoff volume of the Hanjiang River increases with the increase of precipitation but decreases with the increase of temperature, and that the response of the annual natural runoff volume is more sensitive to precipitation changes rather than to temperature changes.