基于WRF驱动的CLM模型对青藏高原地区陆面过程模拟研究

Simulation and Application of the Land Surface Model CLM Driven by WRF in the Tibetan Plateau

NCAR-CLM是目前国际上发展较为完善的陆面过程模型.鉴于大多数研究利用气象站点的数据驱动CLM模型,尝试将WRF气候模型的模拟结果作为驱动CLM的面上强迫场数据来对青藏高原陆面能量特征进行模拟研究.对WRF气候模型模拟的输出结果与青藏高原气象站观测数据进行比较分析表明,WRF模拟输出的气温和向下短波辐射数值与观测值的相关系数大于0.92(p>0.05),气压和比湿的R2在0.80以上(p>0.05),降雨和风速的模拟性能不稳定,但WRF模拟输出的强迫场也可以作为CLM模型的驱动数据.CLM模拟的地表温度、感热和潜热通量与青藏高原气象站观测的地表温度以及涡度通量数据验证分析表明,虽然CLM对地表温度的模拟在合理范围内,但模拟与观测值还是有较大偏差,潜热和感热之间的相关系数分别为0.87和0.68(p>0.05),表明CLM的模拟结果在单点上是可靠的.据此,在此模拟结果基础上分析了青藏高原地区的陆面能量时空分布特征.

NCAR Community Land Model（CLM） is a currently sophisticated land surface model.For the purpose of validating CLM in studying land-atmosphere process in the Tibetan Plateau,the simulated data of WRF（Weather Research and Forecasting Model） by using dynamical downscaling method were applied to the forcing data sets of CLM model.Comparing the observed data from weather stations in the plateau with the air temperature and downward short wave radiation of the forcing data set found that the correlation coefficients between the simulated and observed monthly mean air temperatures and downward shortwave radiations are larger than 0.92（p＆gt;0.05）,and those for atmospheric pressure and specific humidity are larger than 0.80（p＆gt;0.05）.The simulated data of WRF model can be used to drive the CLM model,though it is unstable to simulate precipitation and wind velocity.Thus the simulation performance of CLM in the Tibetan Plateau using ground temperature from weather stations and eddy flux data sets is validated.It is revealed that the simulation of surface temperature is reasonable,but there is larger deviation between simulated and observed surface temperatures.The correlation coefficients for latent heat flux and sensible heat flux are 0.87 and 0.68（p＆gt;0.05）,respectively.Based on the feasible forcing data set and reliable simulation results,the temporal and spatial distributions of energy balance on the Tibetan Plateau are analyzed.