中文摘要：

研究新一代中尺度气象模式WRF中两种大气边界层方案（MYJ，YSU）对沈阳冬季大气边界层结构模拟的影响，重点分析温度层结、低层风场、边界层高度等对污染物扩散有重要影响的气象要素．和观测数据的比对表明WRF基本能够模拟出温度风速的日变化特征，但模拟风速偏大．YSU方案由于模拟的边界层顶卷挟和边界层内混合作用较强，夜间接地逆温强度低于MYJ方案，逆温维持时间比MYJ方案短4小时，同时模拟边界层高度也高于MYJ方案，有利于污染物垂直扩散．边界层高度的3种计算方法中，湍流动能方法计算的边界层高度最高，Richardson数方法次之，位温方法得到的高度最低．Richardson数方法对临界值的选取较敏感．

英文摘要：

Abstract This study analyzed the effects of two difference boundary layer schemes in the Weather Research and Forecast （WRF） model on the simulation of meteorological factors related to pollutant dispersion over Shenyang China in winter. The performance of WRF was evaluated against observation data with statistics. It was revealed that WRF underestimated the temperature and overestimated the surface wind speed which may be attributed to the outdated land use data. The Yonsei University （YSU） scheme simulated higher air temperature and weaker nocturnal surface-based inversion layer than the Mellor-Yamada-Janjic （MYJ） scheme,due to the stronger entrainment at the top of the boundary layer and vertical mixing in YSU. The duration of inversion layer was 4 hours longer in MYJ than YSU. The temperature difference between the two schemes was highest before sunrise, after which the surface heating weakened the difference. The surface wind was not sensitive to the boundary layer schemes and both MYJ and YSU simulated north wind with the highest frequency and speed, agreed with observation. The boundary layer height was also higher in YSU than MYJ, favoring the vertical dispersion of pollutant. Among the three methods determining the boundary layer height, the TKE （Turbulent Kinetic Energy） method led to the highest values, while potential temperature method led to the lowest. The bulk Richardson number method was sensitive to the critical value.