城镇化与绿地退化对城市热环境影响研究

城市的发展和城市化进程的加速,导致建设用地的迅速膨胀和生态景观绿地的急剧减少,最终改变了城市热环境。以广州南部快速发展区为例,基于Landsat6遥感影像数据定量分析城市化及绿地系统的变化情况及其城市地表热场和热岛效应空间分布情况,探讨城市热场及热岛效应受城市化和绿地退化（以NDVI为表征）影响的定量关系。研究表明,广州南部地区的热环境状况与其地形特征之间有较密切的联系,城市热环境的分布变化与城镇建设用地和NDVI的分布变化有一定的相关性,特别是与NDVI呈现线性负相关,即地表温度随着归一化植被指数的增大而降低。结果表明,城镇化与绿地退化是导致城市热岛分布变化的影响因素之一。最后从生态角度出发,提出通过构建城市点状绿岛和带状生态廊道来改善城市热环境的可能性。

Analysis on the influence of urbanization and greenland-degradation on city thermal environment

With the quick development and urbanization progress,more and more land is used for urban construction and then greenland located in the city rapidly reduces,resulting in the deterioration of the city＇s thermal environment.Taking the southern Guangzhou area as example,based on Landsat-6 remote sensing images and quantitative analysis technology,this paper gives quantitative probe to the urbanization of developing area and the variation of green land（presented by NDVI）.And we also study the spatial distribution of city surface heat island effect.We aim to disclose the quantitative relationship among the above two factors.Our study shows that city thermal environment is closely associated with its terrain feature.At certain extend the spatial distribution of city thermal environment flows with the counterpart of its built-up area and NDVI.Mostly thermal environment is negative linear relative to NDVI.In other words where the NDVI is bigger the surface temperature is lower.It can be concluded that urbanization and Greenland-Degradation are the two most important factors to city-heat-island＇s distribution change.At last from ecological view,we bring forth some suggested measures to improve the city thermal environment by constructing a few ecological green-islands and green-galleries among the study area.