Modeling Studies On Land Surface Hydrological Processes In Shuiyangjiang Catchment

Water cycle is the very important physical process in the landsurface processes, to describe the land surface hydrological morerealistically and deal with land surface parameterization too simply,it is needed that seeks reasonable large scale hydrological model,meanwhile which is thought about coupling with land surface model toimprove runoff calculation of former climate model.With thedevelopment of geographical information system GIS and digitalelevation model DEM,anti-distributed hydrological model TOPMODELbased on topography is applied in hydrological modeling research bydifferent country sciences. In this paper, we choose the hydrologicalmodel, firstly which is applied to day and hour discharge modeling forAnhui province Shuiyangjiang catchment to validate its modelingcapacity in the humidity district;Secondly, using DEM data differentresolution(100m,200m,400m,600m,800m,1000m) in the Shuiyangjiangcatchment in the Anhui province, the Sensitivity Analysis of theTOPMODEL's results to DEM Resolution is done using the 365 days dataof 1995 , the analysis results show, with the decreasing of thecatchment's DEM resolution, the drain's river network is changedwhich effects on the model runoff simulation, so the determinationcoefficient of model is decreased ,the modeling results are sensitivityto the DEM resolution, when the model parameterization lnT0 is adjustedusing the relationship between catchment average topography index λ *and lnT0, the determination coefficient of model increased obviously,but it is needed to search its physical explanation;There is complexrelationship between Evapotranspiration and soil vegetation , butbecause the Evapotranspiration is calculated using experientialformulation in TOPMODEL, resulting to calculate Evapotranspirationunreasonably. To improve on the Evapotranspiration calculation ofTOPMODEL hydrological model, the Aerodynamics resistant method of SSiBwhich is a land surface model is used to replace the former method ofthe hydrological model, which makes the hydrological model morereasonable, the results shows that improved model performs better thanthe former model;Lastly , SSiB land surface model is applied toShuiyangjiang drainage basin, to obtain the drainage in the basinoutlet, routing parameterization is used to SSiB, the land surfacemodel is drived by different precipitation data, the study show thatdifferent intensity and spatial heterogeneity precipitation dataimpact on land surface runoff modeling. Due to runoff parameterizationis too simple in SSiB, therefore there is much error in the drainageof simulated and observed, meanwhile runoff simulation is worse thanthe hydrological model.