Abstract : 1C.22
Diurnal precipitation cycle over Austria and its relationship with orographically induced circulations
University of Natural Resources and Applied Life Sciences
Diurnal precipitation patterns over Austria were analyzed for different seasons. This study is based on data from the automatic station network built up in the last 20 years and a few stations with longer records of hourly precipitation data. 132 stations were available for the analysis.
We found that the evening precipitation exhibits a systematic regional pattern and seasonal cycle, reflecting the intensity and timing of convective precipitation. In summer the maximum fraction of evening precipitation was observed over the Alpine main ridge in Tyrol, near the highest mass elevation in Austria. This can be explained by the long continuation of the in-valley wind phase of the thermal wind circulations in the inner Alps. In autumn, a maximum is found in the southeast, presumably orographically enhanced influence from Adriatic air masses. The regions east and north of the Alps show both lower values of the evening precipitation comparatively and a small amplitude in the seasonal cycle. This hints towards an important influence of orographically induced circulations and the valley winds in the diurnal precipitation pattern. The presentation will focus on the complete diurnal cycle of precipitation as a function of season and region.