基于MODIS数据的长株潭地区城市热岛时空分析

基于MODIS影像,采用分裂窗算法反演的地表温度对长株潭地区城市热岛空间分布与季相变化特征、影响因子进行定量研究。结果表明,长株潭地区春季和夏季存在明显的城市热岛效应,而冬季和秋季城市热岛并不明显;地表覆盖类型对城市热岛的影响十分明显,长株潭地区春、夏、秋季植被绿地状况与城市热岛呈现明显负相关分布,其中以夏季最为明显,夏季地表温度与NDVI相关系数的平方R2达到0.8193,即植被覆盖对城市地表温度的影响显著。因此,城市植被的分布与季节变化影响着城市热岛的强度与时空分布,揭示出植被绿地对降低城市热岛效应具有重要的作用,大范围的绿地建设能有效降低城市热岛效应。

Temporal and spatial characteristics of urban heat island in Changsha-Zhuzhou-Xiangtan area based on MODIS data

In this paper,land surface temperature was retrieved by split window algorithm based on MODIS images,and the seasonal characteristics of urban heat island as well as its influencing factors of Changsha-Zhuzhou-Xiangtan area were analyzed using remotely sensed data.The result indicated that there was a clear urban heat island effect in spring and summer in Changsha-Zhuzhou-Xiangtan area,but this did not happen in winter and autumn;it was found that land cover affected urban heat island clearly,the distribution of urban heat island presented a obvious negative correlation with the vegetation in spring,summer and autumn in Changsha-Zhuzhou-Xiangtan area,especially in summer,the coefficient R2 between land surface temperature and NDVI reached 0.8193,that is,the higher vegetation cover was,the less urban heat island was.Therefore,the vegetation has an important effect on alleviating urban heat island.