WRF模式对青藏高原那曲地区大气边界层模拟适用性研究

采用WRF（Weather Research and Forecasting）模式4种边界层参数化方案对青藏高原那曲地区边界层特征进行了数值模拟,并利用"第三次青藏高原大气科学试验"在青藏高原那曲地区5个站点的观测资料对模拟结果进行验证,分析不同参数化方案在那曲地区的适用性。研究表明,YSU、MYJ、ACM2和BouLac方案对2 m气温和地表温度的模拟偏低。BouLac方案模拟的地表温度偏差较小。通过对能量平衡各分量的对比分析发现,温度模拟偏低可能是向下长波辐射模拟偏低以及感热通量和潜热通量交换过强导致的。对于边界层风、位温和相对湿度垂直结构的模拟,局地方案的模拟效果均优于非局地方案。BouLac方案对那曲地区近地层温度、边界层内位温和相对湿度的垂直分布模拟效果较好。 

Evaluation of the WRF model to simulate atmospheric boundary layer over Nagqu area in the Tibetan Plateau

The WRF (Weather Research and Forecasting) Model was employed to simulate the atmospheric boundary layer characteristics over Nagqu area in the Tibetan Plateau. By comparing simulations with results from the comprehensive campaign "The Third Tibetan Plateau Scientific Experiment", four boundary layer schemes were evaluated for their applicability over complicated underlying surface in Nagqu area.The results indicate that the YSU, MYJ, ACM2 and BouLac boundary layer parameterization schemes have cold biases in the simulation of 2 m air temperature and ground surface temperature. The BouLac scheme yields the minimum cold bias of surface temperature. By analyzing components of the energy balance, it was found that the cold bias of temperature mainly came from lower downward long wave radiation and unrealistically strong exchange of the sensible heat flux and latent heat flux. For the simulation of vertical structure of the atmospheric boundary layer, local schemes show better results of wind and relative humidity than that of nonlocal schemes. In Nagqu area, the BouLac scheme has a good effect on simulating surface temperature and vertical distribution of potential temperature and relative humidity in the boundary layer.