MODIS通道1和通道2大气订正的一种快速实用方法

提出了利用气象资料对MODIS影像进行大气校正的一种快速实用方法.读取MODIS前两个通道250min的反射率,采用常用的黑色目标扣除法(Dark-object subtraction)计算天空程辐射,通过卫星过境时刻的气象能见度和水汽资料计算大气透过率,最后推导出目标物的反射率.通过比较两个邻近日期MODIS影像校正前后的归一化植被指数(NDVI)值,得出利用本文提出的方法对MODIS进行大气校正所得到的NDVI值更接近实际情况.结果表明:利用气象能见度和水汽压可以对MODIS数据进行快速有效的大气校正.

A feasible method on atmospheric correction to channel 1 and 2 for MODIS

It is necessary to perform atmospheric correction for extracting quantitative information from MODIS image. A feasible method by which atmospheric correction of MODIS image was performed by using meteorological data was discussed. The reflectance of two bands was obtained from MODIS and the approach is based on DOS method to calculate the path radiance with the reasonable dark-object reflectance choice. The atmospheric parameters at overpass time were evaluated by using interpolation among local meteorological records and the atmospheric transmittance was calculated. At last the reflectance of objects was obtained. This approach was evaluated by comparing MODIS-NDVI in close date before and after atmospheric correction. Results showed that MODIS-NDVI by using this approach is close to true conditions. It will be feasible to use meteorological visibility and vapor pressure data to perform atmospheric correction of MODIS data.