Near-real-time estimation of spectral surface albedo from GOME/ERS-2 and GOME-2/MetOP measurements

Abstract

An algorithm is being developed for estimation of spectral surface albedo from top-of-atmosphere (TOA)-radiances measured by the Global Ozone Monitoring Experiments GOME/ERS-2 and GOME-2/MetOp. The surface albedo is necessary as input for satellite trace gas retrievals, both for near real time and off-line operation. Required is the retrieval of spectral surface albedo with uncertainty less than about 0.01 in the spectral range 310 nm to 800 nm. The algorithm under development estimates Minimum Lambert-equivalent reflectivity (MLER) for a moving time window (for near-real time processing the moving time window can only include measurements from the past). We expect that this advanced MLER-method gives sufficient accuracy for most regions and over most time of the year - for snow-free conditions, in regions with permanent snow cover and for snowmelt periods. Some further refinements are still required to identify and handle with snow build-up periods. The present status of algorithm development and initial results will be presented.