长沙市水体冷岛效应的季节变化及其影响因素

Seasonal Variations of Water Cooling Island Effect in Changsha City and Its Influencing Factors

针对城市热岛现象十分严重的问题,通过研究水体的冷岛效应,旨在探索有效缓解城市高温的解决方案。选取长沙市50个水体,利用代表春、夏、秋、冬四季的4幅Landsat 8遥感数据,探讨了长沙市水体冷岛效应的季节性变化规律及其显著影响因子。结果表明:长沙市的水体冷岛强度随季节变化显著,在夏季最大,春季、秋季次之,冬季最小;水体面积(除冬季外)和水体周围环境中的土地利用类型是影响水体冷岛强度的主要因素,但对海拔高度相差不大的长沙市而言,水体海拔高度及其形状指数在任何季节都不是影响水体冷岛强度的主要因素;水体冷岛强度对于水体面积存在显著的阈值效应,其春、夏、秋三季的水体面积阈值分别为9.79、3.67和4.89 hm^(2)。

In view of the serious problem of urban heat island phenomenon,the cooling island effect of water body is studied in order to find effective solutions to alleviate urban high temperatures.In this study,50 water bodies in Changsha city are selected,and four Landsat 8 remote sensing data representing the four seasons of spring,summer,autumn and winter are used to explore the seasonal variation of the water cooling island effect in Changsha and its main influencing factors.The results are as follows:(1) The intensity of water cooling islands in Changsha changes significantly with seasons,it is the strongest in summer,followed in decreasing order by spring,autumn,and it is the lowest in winter.(2) Land use types surrounding water bodies are the main influencing factor in any seasons,and the size of the water area is the main influencing factor in spring,summer and autumn.However,for Changsha with less elevation difference,both the elevation and the shape index of water bodies are not the main influencing factors on the water cooling island effect in any seasons.(3) There is a significant threshold effect of water cooling intensity on water area,and the optimum thresholds are 9.79,3.67 and 4.89 hm^(2),respectively,in spring,summer and autumn.