P2.7
Land Surface Albedo Retrieval: Simulation Study for NPOESS VIIRS Algorithm
Yunyue Yu, Raytheon Information Technology System Services, Lanham, MD; and T. P. DeFelice, S. J. Cantrell, K. Jensen, D. Cornell, J. L. Privette, and S. Liang
Simulation tools are applied to develop a land surface albedo retrieval algorithm for Visible/Infrared Imagery/Radiometer Suite (VIIRS) that will be on-board the National Polar-orbiting Environmental Satellite System (NPOESS) and its predecessor, the NPOESS Preparatory Project (NPP; launch 2006). The simulation study is focused on the dark pixel surface spectral albedo retrieval process: computation of the black- and white-sky albedo, and the estimation of fraction of the skylight irradiance. The fixed bi-direction reflectance distribution function (BRDF) kernel model of the black- and white-sky albedo computation, the Moderate Resolution Imaging Spectroradiometer (MODIS) approach when few non-cloudy pixels are available, is applied for the VIIRS bands. We also investigated possible combination models, i.e., models with different kernels for different surface type. The inversion process for computing kernel model parameters is investigated for 1) possible precomputing the process with look-up tables, and 2) determination of minimum number of samples needed for the inversion process. The estimation of fraction of the skylight irradiance from aerosol optical depth (AOT) is usually pre-computed as a lookup table. An optimization study of the table size increments, in terms of solar zenith angle and AOT, is performed. Furthermore, a sensitivity analysis for the derived dark pixel surface albedo algorithm is conducted. Simulation tools used for the above study are the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) and the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) program.
Poster Session 2, IIPS Poster Session II
Wednesday, 14 January 2004, 2:30 PM-4:00 PM, Room 4AB
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