Author(s): Xiangyi Ding; Yangwen Jia; Cunwen Niu; Hao Wang
Keywords: WEP; Scale conversion; CMIP3 data set; Climate Change; Water resources
Abstract: It is of great significance to estimate the impacts of climate change on water resources for water resources security, social and economic as well as environmental sustainable development. A physically based distributed model, water and energy transfer processes model in large river basins (WEP-L), which couples simulations of natural hydrological processes and water use processes, is briefly introduced. The WEP-L model is applied to the Haihe River Basin (317,800 km 2) which is subdivided into 3,067subbasins and 11,752 contour bands, and the model is verified by comparing simulated and observed discharges at main gage stations. To estimate the impacts of climate change on water resources, the multi-model average data set provided by National Climate Centre (NCC) based on the World Climate Research Programme’s (WCRP’s) Coupled Model Intercomparision Project phase 3 (CMIP3) multi-model data set under A1B, A2 and B1 scenarios according to the Special Report on Emissions Scenarios (SRES) provided by Intergovernmental Panel on Climate Change (IPCC) in 2000 is used. After data scale conversion using the spatial downscaling method combining RDS (distance square inverse method) with the Theissen Polygon Method, the change processes of hydrological components under different scenarios in 2021-2050 as well as historical conditions in1961-1990 are simulated using the WEP-L model, and the impacts of climate change on water resources as well as the water resources evolution rules are analyzed. The research results illustrate: 1) from the view of average annual variation, comparing with the historical average (1961-1990), although the precipitation in the future 30 years (2021-2050) will appreciably increase, due to the temperature increase, the evapotranspiration will generally increase with a larger extent than the precipitation, resulting that the runoff will decrease, and in the years with more precipitation than the historical average, the flood scale will become larger, while in the remaining years, the drought may be severer; 2) from the view of average monthly variation, comparing with the historical average (1961-1990), the evapotranspiration in every month will increase, the precipitation and runoff will appreciably decrease in flood seasons, while in the remaining months, although the precipitation will appreciably increase, the runoff will decrease with different extents. Therefore, more serious challenge may confront the water resources management and ecology in the basin, and some corresponding countermeasures are suggested.