Revisiting the global mean ocean mass budget over 2005–2020

We investigate the continuity and stability of GRACE and GRACE Follow-On satellite gravimetric missions by assessing the ocean mass budget at global scale over 2005–2020, focusing on the last years of the record (2015–2020) when GRACE and GRACE Follow-On faced instrumental problems. For that purpose...

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Bibliographic Details
Main Authors: Barnoud, Anne, Pfeffer, Julia, Cazenave, Anny, Ablain, Michaël
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2022
Subjects:
article
Verlagsveröffentlichung
Greenland
Antarc*
Antarctica
Online Access:https://doi.org/10.5194/egusphere-2022-716
https://noa.gwlb.de/receive/cop_mods_00062222
https://egusphere.copernicus.org/preprints/egusphere-2022-716/egusphere-2022-716.pdf
Description
Summary:We investigate the continuity and stability of GRACE and GRACE Follow-On satellite gravimetric missions by assessing the ocean mass budget at global scale over 2005–2020, focusing on the last years of the record (2015–2020) when GRACE and GRACE Follow-On faced instrumental problems. For that purpose, we compare the global mean ocean mass estimates from GRACE and GRACE Follow-On to the sum of its contributions from Greenland, Antarctica, land glaciers and terrestrial water storage estimated with independent observations. A significant residual trend of -1.60 ± 0.36 mm/yr over 2015–2018 is observed. We also compare the gravimetry-based global mean ocean mass with the altimetry-based global mean sea level corrected for the thermosteric contribution. We estimate and correct for the drift of the wet tropospheric correction of the Jason-3 altimetry mission computed from the on-board radiometer. It accounts for about 40 % of the budget residual trend beyond 2015. After correction, the remaining residual trend amounts to -0.90 ± 0.78 mm/yr over 2015–2018 and -0.96 ± 0.48 mm/yr over 2015–2020. GRACE and GRACE Follow-On data might be responsible for part of the observed non-closure of the ocean mass budgets since 2015. However, we show that significant interannual variability is not well accounted for by the data used for the other components of the budget, including the thermosteric sea level and the terrestrial water storage. Besides, missing contributions from the evolution of the deep ocean or the atmospheric water vapour may also contribute.

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