Applying a new integrated mass-flux adjustment filter in rapid
update cycling of convective-scale data assimilation for the
COSMO-model (v5.07)
Abstract. A new integrated mass-flux adjustment filter that uses the analyzed integrated mass-flux divergence field to correct the analyzed wind field has been introduced in this work. The filter has been examined by twin experiments with rapid update cycling, using an idealized setup for convective-scale radar data assimilation. It is found that the new filter slightly reduce the accuracy of background and analysis states, however, it preserves the main structure of cold pools and primary mesocyclone properties of supercells. More importantly, it considerably diminishes spurious mass-flux divergence and successfully suppresses the increase of the surface pressure tendency in analysis. For the ensuing 3-h forecasts, the one that employes the filter becomes more skillful after one hour. These preliminary results show that the filter is a promising tool to improve the imbalance problem caused by the data assimilation.