WRF模式对污染天气下边界层高度的模拟研究

大气边界层高度是影响大气污染物浓度的重要因素之一，但数值模式中选择不同边界层参数化方案模拟的边界层高度有很大差异.利用WRF模式中5种边界层参数化方案及2006~2007年春、秋、冬3季河北香河地区激光雷达观测资料，对比分析了污染天气下，不同边界层方案对边界层高度的模拟效果，并分析了误差产生的可能原因.结果表明：5种参数化方案均能模拟出3季污染天气下边界层高度的变化特征，但各方案模拟的边界层高度与观测之间均存在较大误差.模拟的最大边界层高度月变化特征显示，秋冬季的模拟结果与观测值匹配较好，春季偏差较大；模拟的边界层高度日变化显示，均方根误差：春季 > 秋季 > 冬季，且误差在午后（14：00~18：00）更加明显；对该地区而言，非局地YSU方案能较好地模拟污染天气下的边界层高度；各参数化方案中边界层高度计算方法的不同及对大气廓线、湍流动能的模拟差异，可能是造成模拟边界层高度产生误差的主要原因.

Modeling study on boundary layer height in pollution weather by WRF with different boundary layer schemes

Atmospheric boundary layer height (ABLH) is one of important factors affecting concentrations of air pollutants,but different boundary layer (BL) schemes in numerical models could result in uncertainties in predicting ABLH.By using five BL schemes in the Weather Research and Forecast (WRF) model,combined with the Lidar observed data at Xianghe in spring,autumn and winter of 2006 and 2007,this study compared the simulated ABLH with different BL schemes in the pollution periods,analyzed the cause of simulation errors.The results indicated that five BL schemes could capture the variations of ABLH,but there were obvious discrepancies between the simulated and the observed ABLH.In autumn and winter,the monthly maximums of ABLH were modeled better than those in spring.Also,the root mean square errors in diurnal changes of simulated ABLH were assessed with spring > autumn > winter,especially in the afternoon between 2~6pm in local time.The non-local YSU scheme presented the best simulation in polluted days.The ABLH simulation errors could be mainly caused by the differences in atmospheric profiles,turbulent kinetic energy and the ABLH calculation.