Verifying modeled precipitation in mountainous region for heavy precipitation cases

The days with heavy precipitation (accumulation exceeding 200 mm/day) were selected out of the meteorological archives for the area of the South East Alps in Slovenia for the period 1961 - 2000. The best data coverage was for 24 hours accumulations. For these days limited area simulations were performed with mesoscale models using ERA-40 reanalysis as boundary and initial conditions. The model resolution was about 10 km and the simulated precipitation were evaluated using the measured ones. Several strategies to spatially interpolate the measured precipitation in time and space into different regular grids were tested and simulated precipitation were interpolated and evaluated on the same grid as measured ones. The validation results show that it is relatively easy to obtain significant results in the areas of spatially homogenous precipitation while in the mountainous areas of strong precipitation gradients and of the precipitation maxima the results are very much spatial scale dependant. It is difficult to say anything about the quality of model predictions of precipitation if the measured values are having a great spatial variability.