城市形态参数对边界层气象条件影响的模拟

利用耦合城市冠层方案的气象模式WRF，选取高密度城市深圳，通过在模式中设置不同建筑物高度和密度的敏感性试验，研究城市形态参数对边界层气象条件的影响.结果表明：建筑物高度和密度增加会使日间城市冠层对热量的截留作用增强，城市储热分别增加约6W/m²和9W/m²；在城市冠层遮蔽效应和截限作用的共同影响下，建筑物高度增加会使日间地表温度降低约0.3℃，而建筑物密度增大则会引起地表温度增加0.6℃以上，2m温度和地表温度的变化有很好的一致性.城市建筑物高度和密度增加均会引起地表粗糙度增加，造成风速分别降低约0.4m/s和0.6m/s，同时在夜间，由于湍流运动增强，使得夜间边界层高度分别增加约30~40m和20~30m.反之，建筑物高度和密度减小使日间储热减小6~7.5W/m²，10m风速增加约0.3m/s和0.4m/s，夜间边界层高度降低约30~50m和10~30m.

Assessment of urban morphological structure parameters effects on meteorological fields in planetary boundary layer

In this paper, the regional meteorological model WRF with urban canopy scheme has been used to study the impacts of urban morphological parameters on the meteorological fields in planetary boundary layer over the Shenzhen region (high population and building density city). The results from sensitivity experiments showed that the interception of heat in the urban canopy was enhanced in the daytime by the higher building height and density, and therefore the heat storage in the urban areas was also increased by about 6W/m² and 9W/m². Considering the effects of both shading and trapping by the urban canopy, the skin surface temperature was reduced by about 0.3℃ with the increased building height, and the skin surface temperature was increased by more than 0.6℃ in the daytime with the higher building density. In addition, there is a good consistency between the 2m temperature and the skin surface temperature. The wind speed was decreased by about 0.4m/s due to higher building height and 0.6m/s due to higher building density through the increased surface roughness. In the meantime, the nocturnal boundary layer was increased by about 30~40m due to higher building height and 20~30m due to higher building density at night through the enhancement of turbulent motion. On the contrary, the decreases of building height and density reduced the heat storage by 6~7.5W/m² in the daytime, increased the 10m wind speed by about 0.3m/s and 0.4m/s, and decreased the nocturnal boundary layer height by about 30~50m and 10~30m.