利用遥感地表参数分析上海市的热岛效应及治理对策

CHARACTER ANALYLSIS OF HEAT ISLAND IN SHANGHAI CITY USING REMOTE SENSING PARAMETERS

从NOAA-AVHRR数据提取出晴空状况下上海市的地表反照率、地表温度和植被指数参数,分析了冬夏两季遥感地表参数所反映的热岛效应变化。发现在冬夏两季的白天和夜晚都存在明显的城市热岛效应,在冬季夜晚的热岛效应比白天强,而在夏季夜晚的热岛效应比白天弱。这是由于下垫面的差异,导致白天城区地表温度大大超过郊区。城区的地表反照率和植被指数始终小于郊区。进一步的相关分析表明,夏季城市的地表温度与植被指数、地表反照率存在显著的负相关,相关系数分别为-0.975、-0.712。通过提高植被覆盖率和地表反照率,可以减小城市热岛效应。

Remote sensing parameters (surface temperature, vegetation index and surface albedo) are extracted from NOAA-AVHRR data and used to study heat island effect of Shanghai city in summer and winter seasons. The main results of this paper are summarized as follows: there exists obvious heat island effect in Shanghai city during daytime and nighttime in summer and winter season. In winter, heat island effect of nighttime is stronger than that of daytime, however, in summer, the situation is converse, namely, heat island effect of nighttime is weaker than that of daytime due to large difference of land surface between city and suburb. Vegetation index of city is always smaller than that of suburb and surface albedo of city is always smaller than that of suburb. In addition, correlation matrix of these parameters indicates that surface temperature has significantly negative correlation with vegetation index and surface albedo, and their correlative coefficients are -0.975 and -0.712. It means that the measures of increasing vegetion cover and surface albedo can lessen the heat island effect of Shanghai city.