关键词: FY-3B/MERSI影像, FLAASH模型, 大气校正

Abstract:

Based on the FY-3B/MERSI images, MYD09GA products from MODIS and visibility from weather station in Shaanxi, the FY-3B/MERSI images on 26 April, 10 July, 16 November 2012 and 9 January 2013 were corrected by FLAASH model. And on this basis the results of MERSI before and after atmospheric correction were comparatively analyzed, including the reflectivity, NDVI and EVI of MERSI before and after atmospheric correction, and the difference of reflectivity between MERSI before and after atmospheric correction and MYD09GA. The results are as follows: (1) The scattering effect of atmospheric molecules and aerosols was weakened in visible wavelengths after atmospheric correction and the intensity of scatter decreased with the wavelengths, and the ranges of reflection in each channel were obviously widened, which indicated that the phenomenon of different objects with same spectrum was eliminated. (2) Except red bands, the reflectance in invisible wavelengths after atmospheric correction decreased in different seasons, and the decreasing ranges in autumn and winter were larger than that in spring and summer. However, the reflectance in near-infrared wavelengths increased after atmospheric correction except for the 16 channel in autumn and winter. (3) Compared with the surface reflection of MODIS, the differences of FY-3B/MERSI after atmospheric correction were smaller than that before atmospheric correction, and the reflectance of vegetation and residential area after atmospheric correction was well consistent with MYD09GA than that before atmospheric correction. (4) The values of NDVI and EVI for vegetation and habitation areas after atmospheric correction increased, and the increasing of the former was higher than the latter. Furthermore, the differences of NDVI and EVI between vegetation and habitation after atmospheric correction was larger than that before atmospheric correction, the former between vegetation and habitation increased from 0.1828 to 0.2211 and the latter increased from 0.0232 to 0.0251, which would be beneficial to distinguish vegetation and non-vegetation in image classification.

Key words:  FY-3B/MERSI image, FLAASH model, atmospheric correction