Ulrich Meyer

TL;DR: In this paper, a new medium-wavelength gravity field model has been calculated from 110 days of GRACE tracking data, called EIGEN-GRACE02S. The solution has been derived solely from satellite orbit perturbations and is independent from oceanic and continental surface gravity data.

TL;DR: In this article, a satellite-only global gravity field model called EIGEN-GL04S1 was derived by combination of the latest GFZ Potsdam GRACE-only (EIGENGRACE04S) and GRGS Toulouse mean field solutions.

Abstract: The main objective of the US-German twin-satellite mission GRACE (Gravity Recovery and Climate Experiment), launched in March 2002, is a precise survey of the Earth’s time-variable gravity field at unprecedented temporal and spatial scales Temporal changes in the gravity field are related to continuous mass redistributions near the Earth’s surface which are caused by various geophysical and climatologically driven processes Vice versa, transferring the GRACE-based gravity variations into time series of the spatial variability of surface mass anomalies, the mission allows for the first time for a quantification of the ongoing mass transport Such data is of unique importance for a comprehensive modeling, understanding and interplay of these processes In this contribution we give an overview of the basic features of the GRACE satellite mission, the gravity recovery process and the derived gravity products at GeoForschungsZentrum Potsdam (GFZ), as well as the interpretation of the GRACE gravity data with the focus on the detection of hydrological signals This includes a description of the evolution and present status of the quality of GFZ’s GRACE-based global gravity models on the actual fourth model generation (called GFZ-RL04), and an overview of recent findings using GRACE data in hydrological applications

TL;DR: The first ESA Earth explorer core mission GOCE (Gravity field and steady-state Ocean Circulation Explorer) was launched on 17 March 2009 into a sun-synchronous dusk-dawn orbit with an exceptionally low initial altitude of about 280 km as mentioned in this paper.