Representing seasonal water in ECMWF ECLand system

<p>In 2015 lake parametrization was introduced at European Centre for Medium-Range Weather Forecasts (ECMWF) to take into account the impact of lake on the boundary layer and near surface atmosphere. All inland water bodies (lakes, reservoirs, rivers, coastal waters) have constant size distribution and are simulated by the Fresh-water Lake model FLake.</p><p>To introduce water seasonality and reduce errors caused by the constant water distribution, time-varying water maps based on Global Surface Water Explorer (GSWE) data are being introduced in the ECMWF ECLand system. Techniques used to adapt GSWE to create monthly water fraction maps for the use of global NWP modelling and first evaluation results will be presented.</p>