作者： Folke Olesen , Isabel Trigo , Prasanjit Dash , Cristina Madeira
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摘要: The Land Surface Analysis (LSA) Satellite Application Facility (SAF) system, currently operational at Instituto de Meteorologia (IM), Portugal, generates Temperature (LST), with a 15-minute frequency, over the Meteosat-8 disk. LST product is available for European Continent, up to about 60oN, since February 2005, when initial phase of LSA SAF has begun. retrieval based on generalised split-window algorithm, using radiances Meteosat-8/SEVIRI channels 10.8 μm and 12.0 μm, ECMWF forecasts 2m temperature (T2) total column water vapour (TCWV), satellite viewing angle, fraction vegetation cover as input. latter, also one products, used estimation surface emissivity. algorithm applied cloud free pixels, according mask Nowcasting (NWC) algorithm. an elusive quantity, difficult define, thus validate. in LSA-SAF calculated via Planck’s function from directional leaving IR radiance measurements METEOSAT-8 pixels. “Surface radiance” means that atmospheric attenuation along path corrected reflected downwelling removed. “surface” formed by all elements emit radiance. strategy validation within project involves three main tasks, namely: (i) inter-comparison other derived products; (ii) comparison ground-truth sites; (iii) evaluation errors variables input (T2 TCWV). Here we present first results obtained MODIS AATSR LST, after co-locating data each polar-orbiter space time. high sampling rate provides quality information diurnal cycle, while higher spatial resolution polar-orbiters reveals further heterogeneities. Thus, differences between products are analysed terms angle differences, time day properties, including type topographic