应用城市地表能量平衡方案研究城市冠层结构对城市热岛的热力影响

A Study of Thermal Effect of Urban Canopy Structure on Urban Heat Island with Town Energy Balance Scheme

用南京大学区域边界层模式NJU-RBLM,通过对一组理想试验的模拟,研究了TEB方案(town energybalance)和SVAT方案(soil-vegetation-atmosphere transfer)模拟城市热岛现象的差异及本质原因,发现TEB方案对城市热岛(UHI)尤其是夜间UHI模拟效果更优,这是由于TEB方案具备较强模拟城市储热项的能力形成的。此外,深入探讨UHI对大气边界层热力结构的影响,发现UHI现象使城市和郊区的近地层位温廓线在清晨和傍晚都存在明显差异,同时使城市区域气温全天高于郊区,且日间城乡温差能达到的高度明显高于夜间。分析人为热源和建筑物冠层对UHI的影响时发现:人为热源对UHI的影响在夜间强于白天,而建筑物对白天城市湍能的影响强于人为热源的作用。

To study the difference and the reasons of simulating the Urban Heat Island （UHI） with the Town Energy Balance （TEB） scheme and with the SVAT （soil-vegetation-atmosphere transfer） scheme, some ideal numerical experiments are performed with a regional boundary layer model, which is developed by Nanjing University. Results show that because of the great ability of simulating urban heat storage, the TEB scheme is better than the SVAT scheme in simulating the UHI phenomenon. Moreover, the UHI obviously affects the thermal structure of urban boundary layer, that is, there is obvious difference of surface potential temperature profile between urban and rural areas in the morning and the evening. At the same time, urban temperature is higher than rural temperature all through the day. The reaching height of the temperature difference between urban and rural areas in the daytime is higher than that in the nighttime. The anthropogenic heating and building structure play an important role in the UHI. The effect of anthropogenic heating on the UHI in the nighttime is greater than that in the daytime. As far as the turbulence in the daytime over the urban areas is concerned, the effect of buildings is larger than that of the anthropngenic heating.