DOI: 10.5880/igets.we.gfz.l1.001
title: Superconducting gravimeter data of iGrav006 and auxiliary hydro-meteorological data from Wettzell - Supplement to: Landscape-scale water balance monitoring with an iGrav superconducting gravimeter in a field enclosure

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 data set contains superconducting gravimeter data of iGrav006 and auxiliary hydro-meteorological data from the Geodetic Observatory Wettzell (Germany) as a supplement to Güntner et al. (2017, http://doi.org/10.5194/hess-21-3167-2017). In addition, raw gravity and atmospheric pressure data from the observatory superconducting gravimeter SG D030 are available for Wettzell (Wziontek et al. 2017, http://doi.org/10.5880/igets.we.l1.001).
      
      Provided are Level 1 and Level 3 data. The Level 1 product contains raw one-second gravity and barometric pressure time series of iGrav006. These time series are also available together with gravimeter PCB temperature variation in one minute time resolution. Hydro-meteorological time series, namely precipitation measured in-situ with a rain gauge and corrected for undercatch, lysimeter-based precipitation and actual evapotranspiration, reference evapotranspiration, and streamflow measured at gauging station Chamerau are provided as auxiliary time series with hourly resolution. The optional PCB variation-based correction of gravity is part of the auxiliary Level 1 product. In addition, gravimeter calibration file and station logfiles are provided as well. The Level 3 product contains hourly barometric pressure and gravity residuals along with all correction applied to calibrated gravity variation. More detailed information about the time series and their quality can be found in the file headers and logfiles of the individual data files, while details on processing strategy are described in Güntner et al. (2017). 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).
      
      Abstract of Güntner et al. (2017):In spite of the fundamental role of the landscape water balance for the Earth’s water and energy cycles, monitoring the water balance and its components beyond the point scale is notoriously difficult due to the multitude of flow and storage processes and their spatial heterogeneity. Here, we present the first field deployment of an iGrav superconducting gravimeter (SG) in a minimized enclosure for long-term integrative monitoring of water storage changes. Results of the field SG on a grassland site under wet-temperate climate conditions were compared to data provided by a nearby SG located in the controlled environment of an observatory building. The field system proves to provide gravity time series that are similarly precise as those of the observatory SG. At the same time, the field SG is more sensitive to hydrological variations than the observatory SG. We demonstrate that the gravity variations observed by the field setup are almost independent of the depth below the terrain surface where water storage changes occur (contrary to SGs in buildings), and thus the field SG system directly observes the total water storage change, i.e., the water balance, in its surroundings in an integrative way. We provide a framework to single out the water balance components actual evapotranspiration and lateral subsurface discharge from the gravity time series on annual to daily time scales. With about 99% and 85% of the gravity signal due to local water storage changes originating within a radius of 4000 and 200 meter around the instrument, respectively, this setup paves the road towards gravimetry as a continuous hydrological field monitoring technique at the landscape scale.