【摘要】 利用MODIS卫星资料通过暗像元法,对成都及周边地区1万km2范围内的光学厚度进行反演,进而得到该区域内大气订正后的地表反射率以计算增强植被指数EVI,讨论了其在成都及周边地区的特征.研究结果表明:反演区域内气溶胶分布具有明显地域性,成都市及周边区域污染较重,加之扩散条件差,气溶胶光学厚度约为0.8～1.0,西岭雪山和青城山等林地地区光学厚度约为0.2～0.4.大气订正后计算的EVI能够比较准确的反映城市、耕地、草地、森林以及它们交界地带的过渡特征,以及不同地表覆盖类型条件下植被指数的时间变化趋势.更多还原

【Abstract】 Based on the 6S radiative transfer model,the dark target(DT) method proposed by Kaufman(1997) was used to retrieve the aerosol optical depth(AOD) in Chengdu city and its surrounding areas.Then the inversion of enhanced vegetation index(EVI) and the surface reflectance for the VIs calculation was made after atmospheric correction.The characteristics of EVI were also analyzed.The results showed that the aerosol distribution was obviously regional.The values of AOD in the region of Chengdu and the adjacent areas were about 0.8~1.0,as serious pollution and bad diffusion;in contrast,the AOD values of the Xiling Snow Mountains and the Qingcheng Mountains were lower,being 0.2~0.4.Multitemporal profiles of EVI on the surface of various vegetation cover types(city,plantation,sward,forest and others) in Chengdu and its surrounding areas represent their time variation and transitional feature.更多还原