Impacts Of Spectral Response Difference Effects On Sno Calibration

National Satellite Meteorological Center used Simultaneous Nadir Observation (SNO) method to calibrate MEdium Resolution Spectral Imager (MERSI), which is a payload on the Chinese next-generation meteorological satellite FY-3 A during its in-orbit test period. In the SNO process, two remote sensors measured the same target in the almost same time and almost same imaging geometry, slight differences between two sensors' design have become important factors in vicarious calibration. When used SNO method to calibrate FY-3 A/MERSI with EOS/MODIS, the difference between the respected bands spectral response has become an important factor. This dissertation focuses on the quantitative study of apparent reflectance differences caused by differences spectral response.ChapterⅢandⅣare the key parts of this paper. ChapterⅢdescribes the sensitivity experiment at first, and then carries out forward modeling used different targets, such as snow-ice, vegetation, water and sand, at last analysises the impacts of the spectral response function shape to the apparent reflectance. The simulation results show that for the snow-ice, water and sand it can be generally fitted a correction curve to the spectral response differences, but for vegetation it can only be given a range. Meanwhile MERSI band 1 and band 2 spectral responses in infrared spectrum has been studied, analyzed the range of impact for different underlying surface.ChapterⅣintroduces how to get SNO satellite data at first and then collect snow-ice, vegetation, water and sand satellite data. Try to adapt these data respect to spectral response differences. The results showed that, after a revised apparent reflectance, the two stars measured apparent reflectance differences in a certain degree of reduction. However, in some cases, the apparent reflectance differences increased.Concluded some conclusions of this study at last, and proposed the next step study goals.