南京市冬季市区和郊区晴天大气边界层结构对比分析

应用2008年12月24—31日南京市区和郊区同步大气边界层观测资料，对晴天大气边界层结构进行对比分析．结果表明：南京地区冬季晴天，市区近地面层气温高于江北郊区近地面层的气温，市区热岛效应明显，且热岛强度夜间大于白天；市区逆温出现的时间滞后于郊区，逆温层高度也大于郊区．夜间，市、郊区风速随高度不断增大，并在一定的高度出现一个8m／s的极值中心．市区空气相对干燥．通过典型日分析，市区14：00干岛效应显著，相同高度上相对湿度一直低于郊区．在市、郊区近地面层中，愈近地面风速愈小；近地面层中白天风速最大，夜间最小；白天，大气层结不稳定，湍流混合作用强，上下层风速的差别趋于减小．市区风速在低层受建筑物影响．相同高度上小于郊区风速．

Contrastive analysis of atmospheric boundary layer structures in fair weather of winter between urban and suburban areas of Nanjing

Based on the simultaneous observations of atmospheric boundary layer in the urban and suburban areas of Nanjing in the period of 24th to 31 st of December in 2008, A contrastive analysis is made of the atmospheric boundary layer structure on fair days of winter. The results show that in the fair weather of winter, the air temperature near the surface layer in the urban area is higher than that in the suburban area located in the north of Nan- jing. Besides,the urban area has very evident heat island effect,the intensity of which in daytime is stronger than that in nighttime. The time that temperature inversion layer appears in the urban area lags behind that in the suburbs, and the inversion layer height in the urban area is also higher than that in the suburbs. During the night, the wind speed in urban and suburban areas is constantly increasing with different heights and an extreme value center of 8 m/s will occur at a certain height. The relative humidity（RH） in the urban area is relatively low. Based on the analysis of a typical day,the urban heat effect is evident at 14：00 and the RH at the same height in the urban area keeps lower than that in the suburbs. The nearer the wind is to the ground surface, the smaller its speed is;and the wind speed in the near surface layer is the highest in the daytime and smallest in the night. During the daytime, the atmospheric layers are unstable, and the turbulent mixing is strong. Therefore, the difference between the wind speeds in the upper and lower layers tend to decrease. The speed wind at the same height in urban area is smaller than that in the suburbs under the effect of the buildings near the surface.