Gravity Field

The Southafrikan Geodynamic Observatory Southerland (SAGOS)

The Sutherland observatory is designed for high precision geodynamic observations of the Earth using space techniques and ground instruments. The observatory's basic equipment consists of a superconducting gravimeter, a GPS receiver ground-station and a triaxial magnetometer. The Superconducting Gravimeter (SG) records temporal gravity variations from seconds to years. Its large dynamic range and high accuracy permits the recording of weak gravimetric signals of tidal and non-tidal origin as well as free oscillations of the Earth after large earthquakes, core modes and long-term variations as ground-truth data for satellite gravity missions. The SG is an element of a global Gravimeter network of 18 SG stations around the world (Global Geodynamics Project, GGP). The 1 Hz GPS groundstation supports the satellite missions CHAMP and GRACE. The triaxial magnetometer is designed to detect and record pulsations of the Earth's magnetic field due to magnetic storms. The SG data are preprocessed according to international standards (GGP) and fed into the GGP Data Centre hosted by GFZ since 2003.