Impact study of MAP IOP2B observations on the mesoscale numerical simulation

During the MAP IOP2B (19-20 September 1999, the most intensive rainfall period in the MAP SOP) a lot of additional observations e.g. windprofilers, high-resolution radiosondes and surface observations were collected. To study the impact of those observation data/type on the mesoscale numerical simulation, the limited area model ALADIN-AUSTRIA and the ECMWF 4D-Var assimilation experiments on the MAP IOP2B data have been used to carry out the simulations of IOP2B. The ECMWF 4D-Var assimilation experiments are 1) the MAP reanalysis, 2) assimilation without any windprofilers, 3) assimilation with all the windprofilers, including QC rejected windprofilers, and 4) assimilation without any additional MAP observations. The impacts of the windprofiler and the additional observation data on the IOP2B numerical simulation of precipitation, humidity and wind, especially in the regions like Lago Maggiore and Central Po Valley have been investigated.