Research On The Optimization Of Land-surface Hydrological Process In Regional Climate Model

Since the twentieth century,due to the global warming and the negative affections caused by human activities,the hydrological cycle on the earth has changed.At the same time the drought and flood envents in some area are strengthened.There is a great significance to study the relationship between the climate change and the hydrological cycle.It has been proved that there are great advantages and foreground of Regional Climate Model in the area of regional climate simulation.But due to the different land-surface features and circumfluence characteristics,there would present distinguishing simulation effects by the choosing of different parameters.Consequently,it was needed to optimize the parameters to get a suited numerical simulation scheme. Aimed at the characteristics of the simulation domain,especially the shortage of runoff routing calculation in BATS model,the corresponding method of WEP was introduced.With the tools of Regional Climate Model,a basin-scale climate-hydrology coupling simulation model has been set up,which is particularly proper to the Source Region of the West-route of South-to-North Water Transfer Project(the upper Yibin area of Yangze river basin).On the basis of the coupling model,to research the impact of greenhouse gas and land surface change in simulation domain,two experiments were carried out:doubling the density of CO₂ and changing the land cover type.Through this study,conclusions are drawn as follows:â‘ A more accurate result would be obtained by taking Grell as convective precipitation scheme and using NRA data to drive the model.â‘¡The simulated temperature,precipitation,and runoff will more closely to the real under the substituted runoff methods;â‘¢The surface temperature, precipitation,and runoff(especially in summer) will raise,if the density of CO₂ is doubled;â‘£The climate of the research region will trend to warm and drought after grassland degradation.The simulation precision of RegCM was enhanced by the optimization of the land surface hydrological process,which is a key point to the research of climate-hydrology-ecology interactions and influencing mechanism under the climate change and affections of human activities on both theory and practice.