EGU21-10174
https://doi.org/10.5194/egusphere-egu21-10174
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Global sea-level and ocean-mass budgets using advanced data products and uncertainty characterisation

Martin Horwath1, Anny Cazenave2, and the SLBC_cci Team*
Martin Horwath and Anny Cazenave and the SLBC_cci Team
  • 1Technische Universität Dresden, Institut für Planetare Geodäsie, Dresden, Germany (martin.horwath@tu-dresden.de)
  • 2LEGOS Toulouse, F
  • *A full list of authors appears at the end of the abstract

Studies of the global sea-level budget (SLB) and ocean-mass budget (OMB) are essential to assess the reliability of our knowledge of sea-level change and its contributors. The SLB is considered closed if the observed sea-level change agrees with the sum of independently assessed steric and mass contributions. The OMB is considered closed if the observed ocean-mass change is compatible with the sum of assessed mass contributions. 

Here we present results from the Sea-Level Budget Closure (SLBC_cci) project conducted in the framework of ESA’s Climate Change Initiative (CCI). We used data products from CCI projects as well as newly-developed products based on CCI products and on additional data sources. Our focus on products developed in the same framework allowed us to exercise a consistent uncertainty characterisation and its propagation to the budget closure analyses, where the SLB and the OMB are assessed simultaneously. 

We present time series of global mean sea-level changes from satellite altimetry; new time series of the global mean steric component generated from Argo drifter data with incorporation of sea surface temperature data; time series of ocean-mass change derived from GRACE satellite gravimetry; time series of global glacier mass change from a global glacier model; time series of mass changes of the Greenland Ice Sheet and the Antarctic Ice Sheet both from satellite radar altimetry and from GRACE; as well as time series of land water storage change from the WaterGAP global hydrological model. Our budget analyses address the periods 1993–2016 (covered by the satellite altimetry records) and 2003–2016 (covered by GRACE and the Argo drifter system). In terms of the mean rates of change (linear trends), the SLB is closed within uncertainties for both periods, and the OMB, assessable for 2003–2016 only, is also closed within uncertainties. Uncertainties (1-sigma) arising from the combined uncertainties of the elements of the different budgets considered are between 0.26 mm/yr and 0.40 mm/yr, that is, on the order of 10% of the magnitude of global mean sea-level rise, which is 3.05 ± 0.24 mm/yr and 3.65 ± 0.26 mm/yr for 1993-2016 and 2003-2016, respectively. We also assessed the budgets on a monthly time series basis. The statistics of monthly misclosure agrees with the combined uncertainties of the budget elements, which amount to typically 2-3 mm for the 2003–2016 period. We discuss possible origins of the residual misclosure.

SLBC_cci Team:

Martin Horwath (1), Benjamin D. Gutknecht (1), Anny Cazenave (2), Hindumathi Kulaiappan Palanisamy (2, 3), Florence Marti (2), Ben Marzeion (4), Frank Paul (5), Raymond Le Bris (5), Anna E. Hogg (6), Inès Otosaka (6), Andrew Shepherd (6), Petra Döll (7,8), Denise Caceres (7), Hannes Müller Schmied (7, 8), Johnny A. Johannessen (9), Jan Even Øie Nilsen (9,15), Roshin P. Raj (9), René Forsberg (10), Louise Sandberg Sørensen (10), Valentina R. Barletta (10), Sebastian B. Simonsen (10), Per Knudsen (10), Ole Baltazar Andersen (10), Heidi Randall (10), Stine K. Rose (10), Christopher J. Merchant (11), Claire R. Macintosh (11), Karina von Schuckmann (12), Kristin Novotny (2), Andreas Groh (2), Marco Restano (13), Jérôme Benveniste (14). (1) TU Dresden, D; (2) LEGOS Toulouse, F; (3) Centre for Climate Research Singapore, Meteorological Service Singapore, Singapore (4) Institut of Geography and MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany (5) Univ. of Zurich, CH; (6) University of Leeds, UK; (7) Institute of Physical Geography, Goethe University Frankfurt, Frankfurt am Main, D; (8) Senckenberg Leibniz Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, D (9) Nansen Environmental and Remote Sensing Center, Bergen, NO; (10) Technical University of Denmark, DK; (11) University of Reading and National Centre for Earth Observation, UK; (12) Mercator Ocean International, Toulouse, F; (13) Serco/ESRIN, I (14) ESA ESRIN, I (15) Institute of Marine Research, Bergen, NO.

How to cite: Horwath, M. and Cazenave, A. and the SLBC_cci Team: Global sea-level and ocean-mass budgets using advanced data products and uncertainty characterisation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10174, https://doi.org/10.5194/egusphere-egu21-10174, 2021.

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