Die tägliche Druckvariation iiber Mitteleuropa im Sommer

The daily pressure variation having occurred in June 1964 is investigated more in detail. By means of the harmonic analysis of 170 synoptic stations of Central Europe it has become obvious that the phasis of the second harmonics related to local times in this month of unusually small pressure difference is independent from longitude and in the normal way decreases from south to north. Furthermore, the mean local time of the phases shows a time difference compared with the results gained by Bartels 40 years ago of 19 minutes being explained by the fact that the pressure observations of the synoptic stations are made so many minutes earlier than the exact observation time. This thesis is substantiated by the fact that in Berlin, where the pressure readings are made 15 minutes before the observation time, the harmonic analysis results in a phase difference of 14 minutes. The phasis of the first harmonics shows lowest values of the amplitude extending from Belgium to an amphidromy situated over northern Denmark and separating regions of strong daily pressure variations over central Germany and over the North Sea. The highest pressure values are observed in the late afternoon over the North Sea and in the early morning over central Europe, whereas the lowest values are measured in the early morning along the German coasts of the North Sea and in the late afternoon in the interior of the land-covered area of central Europe. It is not only the isolated valleys of the Alpine mountains but the region of the upper Main and Elbe rivers too where the daily amplitude is fairly great, whereas it is lower over central Bavaria.