grid structure of model GME

Triangular grid of the global model ICON.
Mesh displayed in reduced resolution (German Weather Service).

The Atmospheric attraction computation service (Atmacs) provides atmospheric and non-tidal ocean loading corrections for high-precision terrestrial gravity measurements.

Redistribution of masses in the atmosphere and the oceans affect measurements of high-precision gravimeters by means of Newtonian attraction and deformation effects. In order to make other signals visible in the gravity signal, a correction must be applied. Up to 95% of atmospheric effects in gravity time series can be eliminated by a simple linear regression to air pressure variations. However, this is not sufficient for many applications where small signals should be interpreted. Therefore, the spatial distribution of the air masses must be considered, which can be realized using the density derived from parameters of atmospheric models. Moreover, for a complete and precise description of atmospheric effects, the ocean response to atmospheric pressure and winds has to be considered.

Atmacs provides time series for both contributions to loading (Newtonian attraction and deformation) from the atmosphere based on the operational weather model of the German Weather Service (DWD), the Icosahedral Nonhydrostatic global model (ICON). Non-tidal ocean loading effects are also available through Atmacs based on the Max-Planck-Institute for Meteorology Ocean Model (MPIOM) and computed by GFZ.

Currently 62 stations contributing to the International Geodynamics and Earth Tides Service (IGETS) are included in the computation routine. Please follow up the news for latest updates on the service and contact us if you wish your station to be included in the computation.