基于遥感的长沙市城市热岛与土地利用/覆盖变化研究

基于多时相Landsat TM/ETM+影像，首先计算长沙市地表亮度温度，然后利用NDVI(归一化植被指数)、MNDWI(改进 的归一化水体指数)、NDBI(归一化建筑指数)和NDBaI(归一化裸土指数)4个指数，采用决策树分类方法对长沙市影像进行 土地利用/覆盖分类。在此基础上，对长沙市城市热岛的空间分布特征、时空演变特征以及城市热岛与土地利用/覆盖变化和各种影 响因子之间的关系进行研究。结果表明，随着长沙市城区范围的不断扩张，城市热岛范围也不断增大； 土地利用/覆盖类型的变化 会改变地表温度的空间分布，城市用地和裸地是城市热岛强度的主要贡献因素，水体和林地具有较好的降温作用。地表温度与4种 归一化指数的回归分析表明，它们之间存在明显的相关性，不同土地利用/覆盖类型的地表温度存在较大差异。

A REMOTE SENSING IMAGE-BASED STUDY OF THE RELATIONSHIP BETWEEN URBAN HEAT ISLAND AND LAND USE/COVER CHANGES IN CHANGSHA CITY

In this paper,first,the land surface brightness temperature was retrieved by single channel algorithm based on multi-temporal Landsat TM/ETM data,then,NDVI,MNDWI,NDBI and NDBaI indices were calculated to classify the land use/cover types in the study area by the decision tree method and,finally,the spatial and temporal changes of Urban Heat Island(UHI) and the relationship between UHI and land use/cover change in Changsha City were studied.The results show that the extent of UHI increases with the expansion of the built-up area in Changsha City,that the change of land use/cover types is likely to cause the variation of the spatial distribution of Land Surface Temperature(LST),and that the built-up area and the barren land seem to be the major factors responsible for UHI intension,while the water body and the forest land play an important role in reducing LST.Regression analysis shows that there exists a significant correlation between LST and the four indices,and there also exist remarkable LST differences in different land use/cover types.