Quality assessment and improvement of temporally composited products of remotely sensed imagery by combination of VEGETATION 1 and 2 images

Abstract : Global temporal composites of surface reflectances are among the most commonly used products of wide field-of-view satellite-borne instruments such as the Advanced Very High Resolution Radiometer (AVHRR), the MODerate resolution Imaging Spectroradiometer (MODIS) and VEGETATION. The multi-temporal and spatial consistencies of these composites are key elements for their usefulness. In this paper, we use two different criteria to evaluate the quality of existing and new temporal composite products in SPOT–VEGETATION imagery. The first criterion, based on variograms, analyses the spatial characteristics of composite images, and the second one evaluates the quality of the time series based on the analysis of simultaneous imagery from VEGETATION 1 and VEGETATION 2. Thanks to these criteria, we show that the standard deviation of the errors that affect the surface reflectances of current composite products can be reduced by a factor greater than 2 using improved algorithms detailed in this paper. Finally, we produce multi-instrument composites by integrating images from both VEGETATION instruments to further improve the composite products.