Researceh In Couplling WRF Model With The Arid Snowmelt Runoff Model

Snow plays an important role in reginal water reasources and global climate because of its spetial properties different from other land types and the energy mass transfer whith the phase changes of snow . It is a special saturated surface with high surface reflectance.Snowmelt processes simulation becomes a very hot issue in climate change and hydrology reseaches.Accoding to complexity of Xinjiang's spring snowmelt process,this paper setup a distributed snowmelt model based snow energy balance and mass balance method ,which coupled with Weather Research Forecasting model (WRF). A high resolution(at 1 km resolution) Numeric Weather Forecasting System was established with the initial fields and lateral boundaries from by America NCEP/NCAR FNL global reanalysis data . A 24-hours snowmelt runoff-modeling and forcasting system is put forward through using the meteorological results of WRF model .Finaly, with this model system ,this paper took the JunTang River Basin in northern slope of TianShan Mountain as the research area and simulated the process of snowmelt and runoff in 2009 snow season .Meteorological measurement in point-scale,special snow cover date and runoff observation data were used to validate the simulation results . Some conclutions can be arrived in this article:(1) meso-microscale Numeric model WRF,due to reasonable physical equations and advanced model architecture. These spatial meteologic data can force distributed snowmelt model by coupling atmospheric and hydrologic models and do some surport at input data for snowmelt model.(2)One-layer distributed snowmelt model based energy balance method can simulate successfully in low mountain area not only single point but also watershed scale.Snowpack's spatial and time differences and snowmelt-runoff could be better reflected . Erengy input into snowpack changed from day period; Net radiation is the most important branch in total energy flux, contribution as 78 percent about, next to is the turbulent energy ,occupied by 22 percent in snowpack energy input at snowmelt period.(3) WRF meteorological Model Couplling with the arid Snowmelt Runoff Model .Use this system, we simulated snow melt process in the north of Tian shan mountain in 2009. The simulated data shows good agreement with the monitoring data, and indicate the spatial and temporal change of water and energy in snowpack,meanwhile,the snowmelt runoff is also can be arravied, and the certainty coefficient of snow melt runoff in 2009 is 85%, the average relative error of the maximum runoff simulation result is 7.48%. The precision settled for snowmelt runoff model's requirement. This research can procide important reference for the snowmelt process simulation and runoff forecasting in data scarced regions .