Recent advances in land surface modelling at ECMWF

ABSTRACT The land surface physical parameterization used operationally in the Integrated Forecast System (IFS) at the European Centre for Medium-range Weather Forecasts (ECMWF) has been fully revised in its soil, vegetation, and snow components. The current scheme has an improved match to soil moisture and snow field-site observations with beneficial impact on the turbulent fluxes and near surface temperature and moisture as verified by conventional synoptic observations. The gain in hydrological consistency is of crucial importance in order to ease the data assimilation of land surface satellite observations in water sensitive channels (e.g. ASCAT-C-Band active microwave, AMSR-E C-band passive microwave, SMOS L-band passive microwave, etc.). Independent offline verification studies show that the land surface hydrological cycle is in a better agreement with large-scale basins runoff and terrestrial water storage exchange on monthly time-scale. The impact of the revised land surface hydrology is estimated in 1-year global integrations with specified Sea Surface Temperatures (hindcast experiments) showing an overall improvement of the model climate particularly evident near the surface and areas/seasons sensitive to the introduced physical parameterization.

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