Tidal Results of Neighbouring Stations ("Part III" of an old investigation).

On the 10th Earth Tide Symposium in Madrid 1985 an investigation was referred concerning among other tasks tidal gravity results of two similar stations in Berlin and in Potsdam/Germany. There have been compared the results of contemporary time series of two different tidal gravimeters (LaCoste&Romberg ET18 and ASKANIA GS15 No. 222). Deviations of the amplitude factors at both stations were observed with a mean value in the order of 0.7 percent. Nowadays it became possible to perform such measurements with a more up-to-date equipment and to evaluate it with improved methods. So was installed a LaCoste&Romberg (Type G) gravimeter between 1997 and 1999 in turns at both the stations and the time series were analysed using the ETERNA 3.3 analysis program. Deviations of the tidal amplitudes are nearly of the same amount as in the 197811980 measurements but with an opposite sign. Therefore possible reasons are discussed with regard to the quality of the error estimations. Furthermore a lower noise level was observed in both periods at Insulaner station in the inner city of Berlin.