基于Landsat ETM+影像的城市热岛研究

Study on Urban Heat Island Based On Landsat ETM^+ image

采用Landsat ETM+影像数据,分别利用MODTRAN4和FLAASH对热红外波段和可见光、近红外波段进行大气校正,采用Valor的植被指数混合模型估算地表比辐射率,以普朗克公式推算地表温度,并以长沙市为研究区,分析了不同地表覆盖类型以及NDVI与地表温度之间的关系。结果表明,不同地表覆盖类型的地表温度有着显著差异,城市地表温度与NDVI之间具有明显的负相关关系,增加城市的绿地面积有助于缓解城市热岛效应。

The thermal infrared band and the red and near infrared bands of Landsat ETM^＋ data were atmospherically corrected by MODTRAN 4 and FLAASH, and land surface emissivity was calculated by combining vegetation index algorithm from Valor. The land surface temperature was retrieved based on inversion of the Plank＇ s law. And this method was applied to Changsha city, the relationship between urban land cover and land surface temperature were studied, and lhe same work was done between NDVI and land surface temperature. The result showed that promi- nent negative correlation between land surface temperature and NDVI were found in the urban area, and the increment areas of vegetation were helpful to alleviate the urban heat island effect.