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

description: The International Geodynamics and Earth Tide Service (IGETS) was established in 2015 by the International Association of Geodesy. 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 Djougou station (code DJ) in northern Benin, a Sudanian region in West Africa, was established in 2010 thanks to the financial support of INSU-CNRS France and the ANR (Agence Nationale de la Recherche) in the frame of the GHYRAF (Gravity and Hydrology in Africa) project. Continuous time-varying gravity and atmospheric pressure data from DJ are integrated in the IGETS data base hosted by ISDC (Information System and Data Center) at GFZ.
      
The DJ station is the unique permanent station maintained in Africa belonging to the geophysical observatories funded by INSU-CNRS. The superconducting gravimeter is also contributing to the hydrological and meteorological observatory on West Africa called AMMA-CATCH (African Monsoon Multidisciplinary Analysis - Coupling the Tropical Atmosphere and the Hydrological Cycle).
      
The operation and maintenance of the DJ instrumentation is done by staff at EOST/IPG Strasbourg with the help of IRD (Institut de Recherche pour le Développement) in Benin.
      
The DJ station is located in the Ara catchment near the village of Nalohou which is 10 km away from Djougou (longitude: 1.6056 E, latitude: 9.7424 N, height above MSL: 483 m). The local environment is agricultural with mainly fallows and cultivated areas and there is no close industry.
        
There are several buildings belonging to the DJ gravity station. One room is hosting the superconducting gravimeter SG-060 manufactured by GWR Instruments which was installed in july 2010. Another room 5 m away is dedicated to the absolute gravity measurements done regularly with FG5#206 operated by EOST Strasbourg. A third building is for the diesel electric generator that allows powering the installation during the numerous shortages that occur mainly during the monsoonal period in summer.
      
The time series of gravity and barometric pressure from SG-060 starts in July 2010 and is still going on. The time sampling of the raw gravity and barometric pressure data of IGETS Level 1 is 1 minute. Raw data with a time sampling of 1 second will be provided additionally on the seismological IRIS Data Management Center (http://ds.iris.edu/ds/nodes/dmc/).
      
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, DJ station is equipped with auxiliary data supporting the interpretation of the SG measurements, which is, however, not provided in the IGETS data base due to complexity. In addition we benefit from the very dense local network of hydrological and meteorological sensors of AMMA-CATCH as well as from a permanent GNSS (Global Navigation Satellite Systems) station a few meters away from the gravimeter, starting in September 2011.