Abstract (eng)
The distribution of precipitation in Central Europe is largely determined by the Alps. Complex precipitation processes lead to a diverse precipitation climate with high variability at small scales. Differences in the mean rainfall of 1000 mm/a or more are possible within small spatial distance. Since the analysis of precipitation is fundamental for meteorological applications as well as for many other fields, it is necessary to consider the influence of the mountains on precipitation. In the present work, the elevation dependence of precipitation and effects on the precipitation distribution due to orographic lifting are investigated. These effects are taken into account in interpolations of station data using simplemethods. In order to consider elevation dependence of precipitation (Höhenmethode), three different climate datasets are used to calculate regression equations, which describe the distribution of precipitation with altitude. The application of these regression equations to topographical data results in a simulation pattern, which is combined with interpolations of station data. This creates a precipitation field in which topographical structures become visible. A linear model is used to account for the effects of orographic lifting on precipitation (Staumethode).
This model simulates a precipitation pattern for eight different flow directions. The simulations are optimized by comparing them to climatological precipitation fields. Depending on the prevailing flow direction, the best matching simulation pattern is combined with the interpolation of station data. To verify both methods, a cross-validation is carried out. The results in both cases are indifferent with respect to the application of the selected methods. In contrast to the small quantitative differences in the verification results, the application of the regression pattern results in clear optical effects in the final precipitation field where topographical structures become visible. In addition to the crossvalidation, verification scores between the simulation patterns and climatological fields are calculated. Analysis of these scores shows that it is possible to simulate orographic precipitation using the linear model, despite some necessary assumptions.