1966~2015年长江源冰川融水变化及其对径流的影响--以冬克玛底河流域为例

Glacial meltwater variation in Dongkemadi River Basin of Yangtze River source from 1966 to 2015 and its influence on runoff

气候变暖改变了长江源的冰冻圈,影响了当地的生态系统。采用HydroGeoSphere(HGS)水文模型,对长江源区冬克玛底河流域冰川融水进行了模拟研究,以评估气候变暖背景下冰川融水径流对流域水资源的影响。利用研究区周围4个气象站点的资料,采用多元回归和插值方法重建了1966~2015年气象数据,并采用2005~2006年的实测流量数据对模型模拟结果进行了验证,表明模型有一定的可信度。结果显示:①过去50 a,冬克玛底河流域的平均物质平衡为-151 mm/a,冰川物质累积亏损为7.55 m,温度升高对冰川的影响超过降雨增加的影响;②物质平衡与降水呈现正相关,与正积温和冰川融水为负相关;③过去50 a,冬克玛底河流域总径流量、冰川区产流量、非冰川区产流量都呈现增加趋势,其中增加的总径流量的25%为降水增加所致,75%为气温升高导致冰川消融所致。研究结果可为气候变暖背景下长江源的保护提供一定的科学依据和参考。

The freezing circles in the source of the Yangtze River have changed as a result of the globe warming, which has affected the local ecosystem. The HydroGeoSphere(HGS) hydrological model was used to simulate the melting of glaciers in the Dongkemadi River Basin in the source area of the Yangtze River, in order to assess the impact of glacial meltwater runoff on watershed water resources in the context of climate warming. By using the data of four meteorological stations around the study area, the meteorological data from 1966 to 2015 were reconstructed by multiple regression and interpolation method. The measured flow data from 2005 to 2007 and the measured material balance data from 1990 to 2010 were used to verify the credibility of the model. The results showed that:(1) In the past 50 years, the average material balance of the Dongkemadi River Basin was-151 mm/a, and the accumulated loss of glacier material was 7.55 m. The effect of temperature increase on glaciers exceeded the increase of rainfall.(2) Material balance was positively correlated with precipitation and negatively correlated with positive accumulated temperature and glacial meltwater.(3) In the past 50 a, the total runoff,glacier runoff and non-glacier runoff in the Dongkemadi River basin all showed an increasing trend, and 25% of the increase in river runoff was caused by the increase in precipitation and 75% was caused by the melting of glaciers due to temperature rise. The results provide a scientific basis for the protection of the Yangtze River source in climate warming background.