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| Titel |
A Matlab-based Tool for the Analysis of Global Gravity Effects |
| VerfasserIn |
Michal Mikolaj, Bruno Meurers, Andreas Güntner |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093309
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| Publikation (Nr.) |
 EGU/EGU2014-7920.pdf |
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| Zusammenfassung |
| Major sources of gravity variations are related to atmospheric and hydrological
mass variations. The gravity response to these variations must be considered at the
regional to global scale despite the decreasing gravitational effect with the squared
distance from the point of observation. Otherwise, a seasonal signal typical for
large-scale variations remains in gravity residuals and may interfere with the local
signal.
The presented Matlab-based tool for the analysis of global gravity effects, mGlobE,
enables the computation of the global contribution of atmosphere, continental water storage
and ocean variations to gravity variation (loading and attraction part). Global models of the
atmosphere (ERA Interim), hydrological models (ERA Interim, all versions of GLDAS
model or other models) and models of ocean bottom pressure (ECCO-JPL and
ECCO2) are used as input data sets. These models can be freely accessed through the
providers’ web servers and loaded/converted using mGlobE. The package for the
atmospheric effect enables the computation of the global as well as the local contribution.
Thereby, the gravity response to 3D structure of the atmosphere is calculated by a
tesseroid approximation. The additional introduction of an admittance factor for the
pressure difference between observed and modelled values leads to a reduction
of the negative impact of low spatial and temporal resolution of the ERA Interim
model.
The software package for the computation of continental water storage effect enables the
inclusion of minimum five different models. Additionally, global hydrological models like
WGHM or alternative ocean models such as OMCT can be implemented easily. Thus, the
uncertainty estimation of gravity response to continental water storage and ocean bottom
pressure variations is possible.
With mGlobE, all mentioned global gravity effects can be computed for arbitrary
locations. Thus, they can serve for the analysis of gravity variations observed at sites with
superconducting or absolute gravimeters. We show the results of mGlobE for the example of
three gravimeter sites (Conrad, Vienna, Sutherland) and compare these results to data from
other services (ATMACS, GGP/Strasbourg Loading service) and to GRACE-based mass
variations (JPL GRACE Tellus). |
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