Mean number of storm days

Abstract

Precipitation events are the main driving force for hydrological processes; for this reason, correctly compiling the distribution of precipitation in the study area is given high priority. Therefore, three models for assessing precipitation were implemented in DANUBIA: a mesoscale atmosphere model, an interpolation model based on station data and a satellite-supported rainfall retrieval. The satellite- based derivation of precipitation takes place using data from the European Meteosat system. In a fi rst step, the boundaries of the raining cloud areas are delineated. Second, the precipitation rate is assigned considering the precipitation processes identifi ed before. Comparing monthly mean precipitation in the study area for 1999 based on the atmospheric model, the interpolation method and the satellite-based technique reveal shortcomings in identifying stratiform precipitation for the satellite method. On the other hand, weather models have slight weaknesses in calculating convective precipitation. Further results show the average number of storm days from May to September between 1995 and 1999 derived using the satellite retrieval technique. The frequency distribution indicates the expected midsummer maximum in July and reveals an increase in thunderstorm frequency caused by orography within the drainage basin.