研究目的
To characterize the OMI FoV using collocated MODIS reflectance measurements and verify the accuracy of the OMPIXCOR product 75FoV corner coordinates.
研究成果
The OMI FoV is best represented by a super-Gaussian distribution with exponents n = 2 and m = 4, and 75FoV corner coordinates. The FoV changes as a function of viewing angle and is scene dependent. The correlation between OMI and MODIS reflectances decreases and the standard deviation increases when clouds are in the scene. The true OMI FoV is approximated by a super-Gaussian distribution with exponent n = 2 and m = 4, and 75FoV corner coordinates.
研究不足
The study is limited by the scene dependency of the OMI-MODIS overlap function and the time differences between Aqua and Aura overpasses, especially with clouds in the scene. The super-Gaussian function is unsuitable to represent the overlap sensitivity function in partially clouded scenes.
1:Experimental Design and Method Selection:
The study used collocated MODIS and OMI reflectance measurements to characterize the OMI FoV. A 2-D super-Gaussian function with varying size and shape was assumed to represent the OMI FoV. The highest correlation between MODIS and OMI reflectances in cloud-free scenes was found to verify the OMI FoV.
2:Sample Selection and Data Sources:
Cloud-free scenes from 2008 over the Sahara and other regions were selected. MODIS measurements with a much higher spatial resolution than OMI and spectrally overlapping at 469 nm were used.
3:List of Experimental Equipment and Materials:
OMI and MODIS satellite data were used.
4:Experimental Procedures and Operational Workflow:
The OMI FoV was verified by finding the highest correlation between MODIS and OMI reflectances, assuming a 2-D super-Gaussian function. The size and shape of the FoV model were varied to find the optimal overlap function.
5:Data Analysis Methods:
The correlation between OMI and MODIS reflectances was analyzed using Pearson’s correlation coefficient and standard deviation.
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