WRF模式模拟飑线的低层温度偏差分析

Analysis of low-level temperature deviation of squall line simulated by WRF model

为了研究WRF(Weather Research and Forecasting)模式模拟飑线的低层温度偏差问题,选取2009年6月14日发生在江苏省北部的一次飑线个例进行分析。通过WRF模式对此次飑线过程的模拟发现,WRF模式模拟的低层日最高气温滞后实际观测2~3 h,且模拟的傍晚低层气温的降温幅度低于实际观测2~3℃。对比试验证实,通过改变边界层参数化方案可以减弱边界层与自由大气的温度交换,进而在一定程度上改善模拟结果,即模拟的飑线强度和低层温度均与实际观测更加相近;在不改变边界层方案的情况下,将地面自动加密观测站数据加入模拟中也可起到相同的作用。

In order to study the deviation of low-level temperature in squall line simulated by WRF(Weather Research and Forecasting)model,a squall line case in North Jiangsu Province on June 14,2009 was selected for analysis.The simulation results show that the WRF has defects in simulating the diurnal variation of low-level temperature,which mainly show that the simulated daily maximum temperature lags behind the observation for 2—3 h,and the cooling range of simulated low-level temperature in the evening is 2—3℃lower than the observation.Comparative experiments show that by changing the parameterization scheme of the boundary layer,the temperature exchange between the boundary layer and the free atmosphere is weakened,and then the simulation results are improved to a certain extent,that is,the simulated squall line intensity and low-level temperature are more similar to the observations.Without changing the boundary layer scheme,by adding the ground automatic encryption observation station data into the simulation,it can also improve the simulation results.