12/1/2023 0 Comments Earthtime sea level![]() ![]() 2016) and the variations of the ocean mass due to transfer of water between continents and the ocean (Chambers 2009 Leuliette & Willis 2011). 2014), the water storage changes in major river basins (e.g. These components are the ice loss from glaciers (Jacob et al. In particular GRACE measurements have provided since 2002 estimates of many components of the global water budget. By providing the first global, satellite-based, accurate measurement of these exchanges on a monthly basis, the GRACE mission has given unprecedented insights on the Earth water cycle changes in response to the current climate change (Wouters et al. Once corrected for these effects, the variations in the time-varying gravity field represent the water mass exchanges at the Earth surface within and among the ocean, the atmosphere and the water/snow/ice storage on land. The solid Earth processes that can cause significant variations in the Earth gravity field at interannual to decadal timescales include essentially the Earth and Ocean-load tides, the solid Earth pole tide, the glacial isostatic adjustment (GIA) and the earthquakes (at small spatial scale). in the ocean, the atmosphere and on land. Changes in the Earth gravitational field are caused by changes in the mass distribution in the solid Earth and at the Earth's surface, i.e. The Gravity Recovery and Climate Experiment (GRACE) mission sponsored by the National Aeronautics and Space Administration and the Deutsches Zentrum für Luft-und Raumfahrt has been providing precise, time-varying measurements of the Earth's gravitational field since 2002 (Tapley et al. Global change from geodesy, Satellite geodesy, Sea level change, Time variable gravity 1 INTRODUCTION This uncertainty in GRACE estimate implies an uncertainty in the net warming of the ocean and the Earth energy budget of ☐.25 W m −2 (90 per cent CL) when inferred using the sea level budget approach. Their contribution to the uncertainty in GRACE estimate is respectively ☐.21 and ☐.12 mm yr −1 (90 per cent CL). We find that the uncertainty in the geocentre motion and GIA corrections dominate the uncertainty in GRACE estimate of the global water budget. ![]() The uncertainty in the global water budget is ☐.27 mm yr −1 over 2005–2015. The ensemble-mean trend in all global water budget components agree within uncertainties with previous estimates based on different sources of observations. Considering all possible combinations of the different processing parameters leads to an ensemble of 1500 post-processed GRACE solutions, which is assumed to cover a significant part of the uncertainty range of GRACE estimates. We consider variations in six different GRACE processing parameters, namely the processing centre of the raw GRACE solutions, the geocentre motion, the Earth oblateness, the filtering, the leakage correction and the glacial isostatic adjustment (GIA). We examine trends in ocean mass, ice loss from Antarctica, Greenland, arctic islands and trends in water storage over land and glaciers from GRACE data (2005–2015) and explore the associated uncertainty. However, these estimates are uncertain as they show discrepancies when different parameters are used in the processing of the GRACE data. Observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission provide quantitative estimates of the global water budget components.
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