水文模式DHSVM与区域气候模式RegCM2/China嵌套模拟试验

本研究在改进水文 -土壤 -植被模式DHSVM ,用气候观测资料驱动DHSVM进行模拟试验的基础上 ,建立了区域气候模式RegCM2 /China与水文模式DHSVM的嵌套系统 ,将区域气候模式对中国和东亚地区控制试验 (目前气候情景 )和敏感性试验 (未来 2×CO2 气候情景 )结果用双线性插值方法降尺度 (downscaling)到滦河、桑干河流域的 8个气象站点 ,然后再用数字高程模式DEM插值到DHSVM的细网格点 ,驱动水文模式进行嵌套模拟试验。试验结果表明 ,滦河、桑干河流域在未来大气中CO2 浓度加倍情况下 ,地面气温呈一致的增加趋势 ,年平均气温增加2 .8℃ ;两流域未来降水也呈增加趋势 ,滦河、桑干河流域年降水量分别增加 6mm和 4 6mm ;两流域未来蒸发量有所增加 ,年均蒸发量增加 2 9mm ;未来滦河流域年径流深减少 2 7mm ,流量减少 14 .72× 10 8m3 ,桑干河流域径流深增加 2 6mm ,流量增加 12 .2 2× 10 8m3 ,两流域合计 ,流量减少 2 .5× 10 8m3 ;未来滦河、桑干河流域径流深趋向一致 ,分别为 74和 71mm ,约为全国目前平均径流深 2 84mm的 1/ 4。可见 ,两流域未来总体上仍呈现暖干化趋势。本研究发展的嵌套模式系统具有一定的预测能力 ,而且通过参数移植 ,可应用于中国其他流域

NUMERICAL SIMULATION EXPERIMENTS BY NESTING HYDROLOGY MODEL DHSVM WITH REGIONAL CLIMATE MODEL RegCM2/China

Based on improvement of the distributed hydrology-soil-veg etation model DHSVM and its application to North China,a nested regional climatic-hydrologic model system is developed by connecting DHSVM with RegCM2/China.The simulated climate scenarios,including control and 2×CO₂ outputs,are downscaled to 8 stations in Luanhe River and Sanggan River Basins to drive the hydrology model.According to simulation results,under double CO₂ conditions,temperature and evapot ranspiration will rise 2.8 and 29 mm,respectively;precipitation also increases but with different values for each basin,6 mm for Luanhe River while 46mm for Sanggan River;runoff change for the two basins is different too,27 mm decrease for Luanhe River Basin while 26 mm increase for Sanggan River Basin.As a result,the runoff in future for Luanhe River Basin and Sang gan River Basin is 74 mm and 71 mm,respectively,which is approximately a quarter of mean annual runoff(284 mm)of the whole country.Total streamf low for the two basins will decrease about 2.5×10⁸m³.All these indicate that the warm and dry trend will continue in the two river basins under double CO₂ scenarios.The nested model system,with both climatic and hydrologic prediction ability,could also be applied to other basins in China by parameter adjustment.