Essential Gravimetric Variables - Identification and Initial Assessment
Abstract
IAG's Global Geodetic Observing System (GGOS) and its Bureau of Products and Standards (BPS) established the Committee on Essential Geodetic Variables, who shall identify variables needed to characterize the geodetic properties of the Earth. These essential geodetic variables (EGV) shall represent key quantities for sustainable geodetic observations in order to monitor the geometry, the gravity field and the rotation of the Earth (the three pillars of geodesy). The Committee on Essential Geodetic Variables consists of experts from the GGOS science panel and IAG's services and they cover the complete expertise off the three pillars of geodesy.
The primary focus of this paper is the gravity field of the Earth and related essential variables, which are subsequently called Essential Gravimetric Variables (EGrV). With the era of space gravimetry missions (GRACE, GRACE-FO, GOCE) the systematic global observation of the Earth gravity field became feasible. With these missions, on one hand, the spatial resolution of the global geoid as representative equipotential surface of the Earth gravity field could be significantly increased and, on the other hand, for the first time, the long-wavelength time-variable gravity field reflecting mass transport in the Earth system could be observed. Both quantities can be regarded as high level EGrV's, which are the fundament for a number of second level variables. Satellite-based information usually is further processed and combined with other observations in order to further enhance its resolution or in order to identify individual sources of mass transport (e.g. due to ice melting). In many cases these are observations taken on ground or from airborne platforms, but also satellite missions observing other parameters (e.g. the geometric shape of the Earth) might contribute as well. Such information can be regarded as second level EGrV's and it needs to be identified. The final goal should be that all EGrV's are consistent and that they easily can be combined in order to enable a systematic monitoring of the geodetic properties of the Earth. With this paper a first attempt will be made to identify the most important EGrV's and to assess their impact on geodetic and other applications.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.G33A..07G
- Keywords:
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- 1239 Earth rotation variations;
- GEODESY AND GRAVITYDE: 1240 Satellite geodesy: results;
- GEODESY AND GRAVITYDE: 1241 Satellite geodesy: technical issues;
- GEODESY AND GRAVITYDE: 5450 Orbital and rotational dynamics;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS