A Simulation Analysis of the Impact of Climate Change on Runoff in the Manas River

Climate change has significant influence on the hydrologic cycle.Snowmelt runoff is the main of water resources in the arid regions.So,there is great significance to study the influence of climate change on snowmelt runoff.The upper stream of the Manasi River,a typical inland river basin,was selected as the study area in this paper.The studied climate change scenarios were determined based on the changing trend of climate in the study area and global climate modeling(GCM).The runoff has been simulated under 20 climate changing scenarios(random assortment of ΔT=1 ℃,2 ℃,3 ℃,4 ℃ and ΔP=0,±10%,±20%) using SRM model,which based on semi-distributed physical structure.The runoff change rate and the effect of temperature and precipitation on runoff were analyzed according to the simulation.The results show that the annual mean air temperature and annual precipitation had increased during the period from 1971 to 2007.The runoff in the Manasi River would increase with the temperature and rainfall.The snow melting-time would be ahead of time.If temperature raises 1 ℃,the runoff would increase by 13%-16%;if the rainfall increases by 10%,the runoff would increase by 2%.This indicates that temperature and rainfall play important role to the surface runoff of inland rivers.The study is helpful for regional water resources planning under the condition of climate change.