DOI: 10.5880/igets.zu.l1.001
title: Superconducting Gravimeter Data from Zugspitze - Level 1

description: The International Geodynamics and Earth Tide Service (IGETS) was established in 2015 by the International Association of Geodesy IAG. IGETS continues the activities of the Global Geodynamics Project (GGP) between 1997 and 2015 to provide support to geodetic and geophysical research activities using superconducting gravimeter (SG) data within the context of an international network. As part of this network, the Zugspitze Geodynamic Observatory Germany (ZUGOG) was established by the GFZ German Research Centre for Geosciences in September 2018. Continuous time-varying gravity and atmospheric pressure data from the SG at ZUGOG are integrated in the IGETS data base hosted by GFZ. The ZUGOG observatory is located in the European Alps on the summit of mountain Zugspitze, Germany's highest peak, at an altitude of 2938 m above MSL. The operation and maintenance of the ZUGOG instrumentation is jointly done by staff of the Umweltforschungsstation Schneefernerhaus (UFS) and GFZ. The shortest distance to the North Sea coastline is approximately 700 km. The area is close to the seismically active area of the Inn valley/Ester mountains. ZUGOG is located in the research catchment Zugspitze (RCZ; Bernhardt et al. 2018, https://doi.org/10.1007/s00506-018-0510-8) covering an area of 11.4 km² located in the Northern Limestone Alps. Its main characteristics are an annual precipitation of more than 2000 mm at an average temperature of -4.5°C. The altitudes vary between 2962 m (summit of mountain Zugspitze, Germany’s highest peak) and 1430 m at Partnach spring where the catchment is drained solely due to the special geological situation. The catchment is therefore regarded as lysimeter and especially suitable for studies on water balance. Germany’s highest and largest glaciers - the Northern and Southern Schneeferner – are also located in the RCZ as well as permafrost rock walls in mountain Zugspitze. The observatory is a former laboratory of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. The special architecture of the lab prevents snow accumulation on the roof above the sensor. Due to the high altitude, the gravimetric footprint can be largely increased. The room has a ventilation system, and the SG is additionally insulated in a box with heaters. The first concrete pier is occupied by the SG, while the second one is intended for absolute gravimeters (first measurements in Oct 2018, second measurements in Sep 2019 both by Ludger Timmen from Leibniz Universität Hannover) and other instruments. A continuous GNSS station is installed nearby as well as a snow balance and 5 snow height sensors for the monitoring and modelling of near-field effects. ZUGOG is a high precision geodynamic observatory comprising space techniques and ground instruments. Presently, the observatory is equipped with the SG 052 manufactured by GWR Instruments, one of the two SGs operating in parallel at Sutherland, South Africa, until September 2017 (Förste et al., 2016, http://doi.org/10.5880/igets.su.l1.001). The time series of gravity and barometric pressure from the SG D037 starts in September 2018, however, with a malfunction in the beginning until 29 December. The SG is active and the time series is kept up to date regularly with a time delay of a few months. The time sampling of the raw gravity and barometric pressure data of IGETS Level 1 is 1 second and 1 minute. For a detailed description of the IGETS data base and the provided files see Voigt et al. (2016, http://doi.org/10.2312/GFZ.b103-16087). In addition, ZUGOG is equipped with auxiliary data supporting the interpretation of the SG measurements, which is, however, not provided in the IGETS data base due to their complexity. These are a local network of hydrological and meteorological sensors as well as a permanent GNSS (Global Navigation Satellite Systems) station.