Assimilation of radar precipitation data in NWP Models — a review

The COST 717 Action has a working group (No 3) on ‘Using Radar Information for Assimilation into Atmospheric Models’. As an initial part of its plan, the group is reviewing previous attempts to assimilate radar data. The main techniques used to assimilate precipitation data — physical initialization, latent heat nudging and variational assimilation are described. Most previous studies have worked with surface rain rate estimates, but attempts to assimilate reflectivity directly are also covered.