气候变化对黄河源区水资源的影响

利用气候模型结果和大尺度分布式水文模型评估黄河源区未来的水资源.根据IPCC DDC的13个系列的GCMs成果,结合黄河源区的实测气象资料,分析了该地区气候在未来100 a内的可能变化;建立了考虑融雪和冻土影响的分布式水文模型,经验证该模型能够适用于黄河源区.计算出了相应的径流情景,分析了黄河源区水量尤其是水资源特性(径流的年内、年际分布)的可能变化;对南水北调西线工程的需水量进行了简单评估.

Impact of Climate Change on Runoff in Source Region of Yellow River

A visible climate change in China,together with the global change,is outlined in detail in the IPCC’s reports.The head regions of Yellow River supply about 1/3 water of the whole river basin.The impact of global worming is much sensitive in the high and cold regions.So it is important to make clear the change of water resources under changing climate in the regions.Observations in the past 50 years show that the temperature in the regions increased 0.02 ℃ per year,while the precipitation fluctuated without any obvious trend.13 Scenes under 2 SRES from 7 GCMs are downloaded from IPCC’s DDC.Validation shows that the average of 7 GCMs’ results is better than individual one and Scene B2 is more rational than Scene A2.Prediction of the future 100 years shows: temperature will increase continuously,especially in Huangheyan Station,while precipitation will be inconsistent among the GCMs’.Overall trend of all scenes seems to have a fluctuation before 2030 and then increase.A distributed hydrological model is established to derive runoff change from climate change,with a cell size of 25 km×25 km and a time step of 24 hours.The effects of snow,glaciers and permafrost are taken into consideration in the model.The parameters of the model are calibrated by 30-year(1961-1990) observations,and validated by the observations of the following 10 years.Runoff forecasted in the validation fits well with observations.Water in the future 100 years in the study regions will fluctuate in the early 20 years and then will decrease about 5% per year.The trouble of washy or drouthy years will increase,and the interannual variation will increase as well.The water demand in the line of Western Route Project of South-North Water Diversion is discussed briefly.