Reduction of the Topographic Effects on Remotely Sensed Images from High Latitudes

Abstract

Satellite images from high latitudes are highly dependent on topography due to the low solar angle. A correction method based on a parametric radiance model and using a digital elevation model (DEM) is presented. The radiance model gives each pixel value as a parametric function of a ground cover dependent reflectance factor, and the irradiance, which are calculated from the DEM and the solar angles. An algorithm for estimation of the model parameters from well kndwn field reference points is stggested. In a test using a Landsat TM image from Ny-Alesund (79 N, 12 'E), Svalbard, inaccuracies in the DEM were the main source of error.