Simulative study of future climate and hydrological change over the Yellow River basin

A macro-scale and semi-distributed hydrologic model (VIC) was applied in the upper-middle reach of the Yellow River (above the Huayuankou Hydrological Station), and the regional climate model RegCM4.0 one-way nested by the global model BCC_CSM1.1 was used to downscale climate simulation to drive the VIC for simulating the future climate and hydrologic changes over the Yellow River basin under the new RCPs scenarios (RCP4.5 and RCP8.5). The simulation results show that, under RCP4.5 and RCP8.5 scenarios, annual mean surface air temperature in the future will arise apparently. In the periods of 2019-2048 and 2069-2098, relative to the reference period 1971-2000, temperature will arise 1.2-1.5℃and 2.19-3.9℃,respectively. The annual mean precipitation will slightly increase, with the rate of 6% in 2019-2048, and 1.4%-5.6% in 2069-2098. The annual mean evaporation will distinctly increase, with the maximum rate of 9.6% in 2069-2098. However, the annual mean runoff in Huayuankou Station in 2019-2048 will increase by 3.4% to 7.4%, while decrease by 3.3% to 5.3% in 2069-2098. In the upper reach of the Yellow River, the general climatic and hydrological trends are the same as the whole basin, but the annual mean runoff in the upper reach will remain the stable level in the future, the decreasing rate will be much less than the one in the whole basin.