南京市小气候日变化规律及其对人体舒适度的影响

Diurnal variation patterns of microclimate and their effects on human comfort degree in Nanjing City

于2005年7—9月,对南京市市中心繁华区、水体、郊区空旷地和森林绿地4个不同生境的日平均温度、湿度和风速等气象因子进行了24h定点同步观测。结果表明:各点于翌日4:00出现气温最低值,13:00—14:00出现最高值,森林绿地日平均气温最低,市中心繁华区最高,市中心繁华区、水体于17:00气温突增,市中心繁华区和郊区空旷地气温日振幅较大;各观测点相对湿度最高值时段为0:00—翌日5:00,16:00—17:00为湿度最低时段,森林绿地日平均湿度最大,市中心繁华区最低;森林绿地、郊区空旷地的风速、风速变化幅度白天大于夜晚,风速11:00—12:00开始变小;南京市气候呈弱热岛效应,城郊日平均温差<0.5℃;热岛对人体舒适度有负面影响,市中心繁华区、城市郊区空旷地白天人体舒适度始终低于森林绿地。

In July-September 2005, a 24 hours synchronous observation was conducted on the air temperature, relative humidity and wind speed in the urban center, urban lake, suburb, and urban forest of Nanjing City, aimed to investigate the effects of the diurnal variation patterns of these microclimatic factors on the human comfort degree in these habitats. The results indicated that in all test habitats, air temperature was the lowest at 4：00, and the highest at 13：00.2 14：00. Urban forest had the lowest mean air temperature, while urban center had the highest one. The air temperature in urban center and urban lake increased rapidly at 17：00, and that in urban center and suburb had a larger diurnal variation range. The relative humidity in the four habitats was the highest at 0：00-5：00, and the lowest at 16：00-17：00. Urban forest had the highest humidity, while urban center had the lowest one. Wind speed and its variation range in urban forest and suburb were bigger at daytime than at night, and the wind speed decreased at 11：00-12：00. There existed a weak ＇ heat island effect＇ in Nanjing, with a diurnal difference of mean air temperature less than 0.5 ℃ between urban center and suburb. The human comfort degree at daytime in Nanjing was always higher in urban forest than in urban center and suburb.