Monitoring regional atmospheric stability with hyperspectral satellite observations enhanced with a potential network of ground-based microwave radiometers

This study attempts to assess the potential benefit of a network of ground-based microwave radiometers (MWR) in variable configuration in synergy with simultaneous geostationary satellite observations from the future Meteosat Third Generation Infrared Sounder (IRS) for observing regional atmospheric stability. Since both observation types do not yet exist, reanalysis fields of the western part of Germany (Rhein-Ruhr-Area) were used to simulate MWR and IRS observations. From these simulations, neural network retrievals for CAPE and Lifted Index (LI) were derived for satellite only (IRS), ground-based only (MWR) and for synergistic (IRS+MWR) observation configurations. The developed retrievals were applied to two years of simulated observations. In general, the IRS+MWR retrievals outperform (up to 0.3 improvement in Heidke Skill Score) the IRS retrievals under clear sky and especially under cloudy conditions, if both observation types are available simultaneously and at the same location. The impact of adding one to 200 MWRs of the hypothetical observation network to the satellite observations was investigated using a spatial statistical interpolation method. The fields of CAPE/LI from IRS observations were merged with the CAPE/LI values from the MWR network by taking into account the corresponding error covariance matrices of both retrievals, which were derived from reanalysis data. It was shown that the contribution of ground-based observations is more pronounced under cloudy conditions and is most valuable for the first 25 sensors located in the domain.