EUMETNET opens to microwave radiometers for operational thermodynamical profiling in Europe

It is recognised that from the perspective of numerical weather prediction (NWP) and mete- orological fore- and nowcasting the atmospheric boundary layer (ABL) is one of the most undersampled regions of the atmosphere. Indeed, the widespread weather stations primar- ily measure at or close to the surface whereas observations from satellites have difficulties at the lowest altitudes due to cloud shadowing, surface emissions or broad averaging ker- nels, depending on technology (Illingworth et al. 2019, and references therein). On the other hand, commercially available ground-based microwave radiometers (MWR) operating in the K- and V-band (20–60 GHz) for temperature and humidity observations, respectively, are most sensitive to this lowest part of the atmosphere by their observation geometry and scanning strategy as well as by the choice of spectral channels. At the same time, MWRs have reached a high level of maturity and are therefore suited for operational networks and could contribute to closing the observational gap in the ABL. This conclusion was drawn by the recently completed COST action TOPROF (Illingworth et al. 2019). Based on these considerations, the consortium of European Meteorological Services EUMETNET mandated its observation programme E-PROFILE to produce a business case for the federation of a European network of existing MWR. The investigations were based on the one hand on stakeholder needs and requirements from official documentation of the World Meteorological Organisation (WMO) and EUMETNET as well as from a dedi- cated user survey. On the other hand, considerations of technological maturity and expected benefits for the meteorological community have been assessed from published scientific studies.