SMOS long term assessment based on re-analyses: strategy and work plan

This document proposes a long-term strategy and work plan to assess the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) soil moisture and brightness temperature products. It proposes different strategies and work plans for the Near Real Time (NRT) brightness temperature product and for the two SMOS neural network Soil Moisture (SM) products developed for ESA and for the European Centre for Medium-Range Weather Forecasts (ECMWF) assimilation purposes. The proposed approaches are based on SMOS-dedicated monitoring suites to compute first guess departure statistics against the ERA5 reanalysis. Brightness temperature monitoring is proposed to rely on the Integrated Forecasting System (IFS) monitoring suite adapted to SMOS. Soil moisture monitoring suites for both the ECMWF and the ESA neural network products, are proposed using the surface stand-alone analysis with ERA5 atmospheric analysis forcing. The monitoring suites will be based on IFS cycle 46r1 developments that allow to ingest SMOS neural network soil moisture products (ECMWF 2019). The required input data sets are described, and a detailed work plan is proposed with corresponding required resources.