Analysis of co-located measurements made with a LaCoste&Romberg Graviton-EG gravimeter and two superconducting gravimeters at Strasbourg (France) and Yebes (Spain)

Abstract

Two experiments of intercomparison between the LaCoste&Romberg Graviton-EG1194 spring gravimeter and the superconducting gravimeters SG-026 and OSG-064, operating respectively at J9-Strasbourg (France) and CDT-Yebes (Spain), were analyzed. The main objective was to check the instrumental response of the spring meter, both in amplitude and phase as well as its time stability. A general conclusion is that normalization factors have been obtained with a similar ratio for main diurnal constituent O1 at both observing sites. The accuracy of scale factors was determined at the level of 0.03 % (at J9-Strasbourg) and 0.1 % (at CDT-Yebes). For the semidiurnal constituent M2, slight differences were found at J9-Strasbourg, which would require further investigations. Site effects were also demonstrated by considering the different response of the spring gravimeter to tilts and atmospheric pressure variations at both sites.