Global and regional seasonal variations of the geoid detected by GRACE

Abstract

Since 2002, the US-German GRACE (Gravity Recovery and Climate Experiment) mission has been providing a precise survey of the Earth's time-variable gravity field, with unprecedented temporal and spatial sampling. GRACE time-variable gravity fields provide a means of measuring the temporal and spatial variations of mass redistribution within the Earth system. The GRACE mission has started a new era in studying a series of geophysical problems ranging from deep Earth structure to tracking mass redistribution on and near the surface of the Earth. Time variability of the gravity field presented here is based on the transformation of "monthly gravity field models" to the geoid. We show the changes caused by the global water cycle and land hydrology.

Gravity field and ocean tides modeling for precise orbit determination of DORIS satellites

“…Since 2002 the GRACE mission -consisting of two satellites arranged for the low-low satellite-to-satellite tracking -has been producing monthly geopotential models by means of which time-variable gravity can be observed. For the first time, a time series of gravity variations due to continental and regional hydrology changes can be detected from space (Tapley et al, 2004;Kostelecký et al, 2013). Currently, the low degree part of the most accurate static gravity field models (up to degree 150, say) is derived from GRACE mission data (e.g., Pail et al, 2010).…”