南京城区近地表不同地面覆盖层热岛效应观测与分析

在2008年7月27～28日南京城郊14个观测点温湿度观测数据的基础上,对南京城区、环玄武湖区和郊区的水泥地面、草地以及地面以上80cm高程近地表处的大气温湿度日变化规律、热岛效应和干岛效应强度进行了分析。结果表明:①南京城区近地表的热岛效应十分明显,城郊最大日平均温差:水泥地为3.1°C,大气为1.9°C,草地为1.2°C;②环玄武湖区水泥地的热岛效应明显,但近地表的大气和草地的热岛效应几乎不存在;③城区干岛效应明显,城区湿度比郊区明显要小,其中水泥地的平均湿度差最大,达到-14.1%;④城区湿度与温度呈相反的日变化规律,且湿度的变化主要取决于大气的温度变化;⑤南京城区雨花台、新街口、南汽和夫子庙等地的热岛效应较强,城市中的湖泊和草地对缓解城市热岛效应有显著的作用,而城市中的水泥地面对城市热岛效应起到明显的加剧作用,长江对城西地区的热岛效应起到消解作用。

Observation and Analysis of Near-surface Urban Heat Island Effect on Various Ground Covers in Nanjing City

Based on the temperature and humidity data measured at 14 observation sites in Nanjing during July 27 and 28,2008,the diurnal variation of surface temperature,air temperature and humidity at 80 cm above ground were analyzed.The intensity of UHI and urban dry island(UDI) in three distinct zones,i.e.urban zone,rural zone and Xuanwu Lake zone,and the effect of typical surface covers(cement and grass) were discussed.The results show that:(1) the near-surface UHI effect is evident in Nanjing city,the maximum diurnal average temperature difference between urban zone and rural zone is 3.1°C on cement cover,1.9°C in air and 1.2°C on grass cover;(2) the UHI effect in Xuanwu Lake zone is evident on cement cover,but insignificant in air and on grass cover;(3) The UDI effect in urban zone is evident,the humidity in urban zone is much lower than rural zone and the difference reaches-14.1% on cement cover;(4) the diurnal variation of the humidity is contrary to that of temperature and significantly depends on temperature;(5) it is observed that,in urban zone,Yuhuatai,Xinjiekou,Nanqi and Confucius temple areas show relative high UHI intensity.The city lake and grass cover play an important role in reducing the UHI effect,while the cement cover can intensify the UHI effect.The Yangtze River located in the west of Nanjing can reduce the UHI effect in Hexi area.