2:30 PM - 2:45 PM
[G07-1-05] Observing the Earth's gravity field as integral component of the Global Geodetic Observing System
invited
Observing the Earth's gravity field addresses in several aspects the mission of GGOS. It provides a) the direct observation of mass variations (due to geophysical signals) and mass transport processes, b) a physical height reference surface, with respect to which very small change processes can be described, and c) the definition of the datum of the terrestrial reference frame.
The first generation of satellite gravity missions (CHAMP, GRACE, GOCE) has revolutionized our picture of the static and time-variable gravity field. However, due to signal attenuation with altitude gravity models based on satellite data are restricted to 70-80 km wavelength, so that a combination with ground data is still indispensable for high-resolution applications such as the definition and global unification of height systems. Service applications with significant societal benefit such as forecasting of floods and droughts or water management require not only a higher spatial resolution, but also the provision of the temporal changes of the gravity field in near real-time.
In this paper the achievements, but also limitations of the current observation of the Earth's gravity field are discussed. An inventory of the GGOS satellite infrastructure, which is needed to achieve the GGOS 2020 goals, performed by the GGOS Standing Committee on Satellite Missions, has revealed that that gravity field missions are the most critical component to be continuously maintained in the future. Therefore, current international activities to advocate satellite gravity missions and thus to foster a sustained gravity field observations system from space as integral component of the GGOS satellite infrastructure in the future are presented, and the added value of improved measurement technology and innovative mission concepts is discussed. Finally, special emphasis will be given to the gravity field contributions to a globally unified height system as integral part of a Global Geodetic Reference Frame.
The first generation of satellite gravity missions (CHAMP, GRACE, GOCE) has revolutionized our picture of the static and time-variable gravity field. However, due to signal attenuation with altitude gravity models based on satellite data are restricted to 70-80 km wavelength, so that a combination with ground data is still indispensable for high-resolution applications such as the definition and global unification of height systems. Service applications with significant societal benefit such as forecasting of floods and droughts or water management require not only a higher spatial resolution, but also the provision of the temporal changes of the gravity field in near real-time.
In this paper the achievements, but also limitations of the current observation of the Earth's gravity field are discussed. An inventory of the GGOS satellite infrastructure, which is needed to achieve the GGOS 2020 goals, performed by the GGOS Standing Committee on Satellite Missions, has revealed that that gravity field missions are the most critical component to be continuously maintained in the future. Therefore, current international activities to advocate satellite gravity missions and thus to foster a sustained gravity field observations system from space as integral component of the GGOS satellite infrastructure in the future are presented, and the added value of improved measurement technology and innovative mission concepts is discussed. Finally, special emphasis will be given to the gravity field contributions to a globally unified height system as integral part of a Global Geodetic Reference Frame.