Development of a prototype snow albedo algorithm for the NASA MODIS Instrument
نویسندگان
چکیده
A prototype snow albedo algorithm has been developed for the Moderate Resolution Imaging Spectroradiometer (MODIS). The prototype algorithm is designed to enable daily snow albedo determination for cloud free areas mapped as snow by the MODIS snow-mapping algorithm. The bidirectional reflectance distribution function (BRDF) of snow is modeled using a discrete ordinates radiative transfer model to allow for the correction of anisotropic scattering effects over non-forested surfaces. For forested areas, a simple Lambertian scattering model is assumed. The effects of illumination and viewing geometries are also considered in the albedo determination. Initial prototyping efforts were accomplished using MODIS Airborne Simulator (MAS) data acquired over Wisconsin and New York during January and February 1997. Despite limited concurrent field observations for validation, the prototype algorithm’s performance appears reasonable in the visible part of the spectrum. However, correction for anisotropic scattering effects in the shortwave infrared region of the spectrum remains problematic.
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