Short‐wave radiances: comparison between SEVIRI and the Unified Model

摘要: The radiation scheme in the Met Office Unified Model (UM) is extended to allow calculation of short-wave radiances. Comparisons between reflectances simulated with global forecasting configuration UM and observations from SEVIRI (Spin Enhanced Visible Infrared Imager) on board Meteosat 8 are presented. One main purposes for such a comparison model validation, since it allows us directly compare satellite reflectances, without having make use retrieval systems. Eliminating algorithm has advantage that we can be certain any discrepancies modelled measured radiances due inaccuracies model, rather than differences assumptions made both algorithm. In principle, this should detect weaknesses parametrizations. In particular, four channels corresponding radiance simulations obtained over oceanic regions. Generally good agreement observed was visible channels, but greater disagreement found NIR 1.6 IR 3.9 hinting at deficiencies model's representation particle size. Sensitivity studies carried out explore these sensitivities.