Assimilation of surface albedo and vegetation states from satellite observations and their impact on numerical weather prediction

The impact of assimilating these near-real-time (NRT) products within the land surface scheme of the European Centre of Medium-Range Weather Forecasts (ECMWF) is evaluated for anomalous years. It is shown that: (i) the assimilation of these products enables detecting/monitoring extreme climate conditions where the LAI anomaly could reach more than 50% and in wet years albedo anomaly could reach 10% , (ii) extreme NRT LAI anomalies have a strong impact on the surface fluxes, while for the albedo, which has a smaller inter-annual variability, the impact on surface fluxes is small, (iii) neutral to slightly better agreement with in-situ surface soil moisture observations and surface energy and CO2 fluxes from eddy-covariance towers is obtained, and (iv) in forecast using a land-atmosphere coupled system, the assimilation of NRT LAI reduces the near-surface air temperature and humidity errors both in wet and dry cases, while NRT albedo has a small impact, mainly in wet cases (when albedo anomalies are more noticeable).