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Sea Level Budget Closure Project

 

 

Sea level is one of the most prominent indicators of climate change. It integrates changes of several components of the climate system in response to anthropogenic forcing as well as natural forcing factors related to natural sources and internal climate variability. Present-day global mean sea level rise primarily reflects ocean warming (through thermal expansion of sea waters) and land ice melt. Changes in land water storage constitute an additional contribution.

As a primary objective of the ESA CCI programme was to reduce current uncertainties of sea level change and its individual components, better closure of the sea level budget should now be possible. This will improve our understanding of processes involved in causing global mean sea level rise and its regional variability, and further help to improve models used for projections of future climate changes.

Closure of the sea level budget implies that we have:

ΔSL(t) = ΔMOcean (t) + ΔSSL(t)

where ΔSL(t) is time-variable sea level, ΔMOcean(t) is time variable ocean mass component,
ΔSSL(t) is steric sea level components (effect of the depth integrated change in sea water density due to ocean temperature and salinity variations).

Water mass conservation in the climate system implies closure of the ocean mass budget:

ΔMOcean (t) = [ ΔMGlaciers(t) + ΔMice sheets(t) + ΔMLWS(t) + ΔMAtm(t) + missing mass terms ]

where the ΔM(t) terms in the right hand side refer to glacier and ice sheet mass balances, changes in land water storage (LWS, including seasonal snow cover), and atmospheric water vapour.

Studying the sea level budget and the ocean mass budget with accurate climate records will bring major scientific benefits – adding confidence to satellite-based assessments of climate change, shedding light on missing or poorly known processes such as land hydrology that remain a challenge for Earth Observation, or heat uptake by the deep ocean. This will allow the key processes affecting sea level rise to be precisely quantified, leading to more informed model projections. Together with extreme events like storm surges and tropical cyclones, regional/local sea level changes represent a major threat in low-lying, highly populated coastal regions of the world, each of which affects coastal planning. The project is therefore a timely opportunity to add societal value and visibility to the CCI, allowing it to form the backbone of a milestone contribution to climate science.

This project intends to analyze in an integrative context recent results obtained by the ESA CCI programme for the sea level, glaciers and ice sheets Essential Climate Variables (ECV), with additional account for assessments of the ocean thermal expansion component which utilize the CCI Sea Surface Temperature ECV. Among other objectives, an important task will consist of assessing the quality of the CCI products involved in the sea level budget.

The study time span will cover the precise altimetry era (starting in 1993). A special focus will be given to the period 2003/2005 to 2015, coinciding with the availability of GRACE space gravimetry data, and Argo drifter data (providing the steric component for the 0-2000m ocean depth, with almost complete 3-D coverage of the oceans).

The project will also address the regional variability in sea level and sea surface temperature, and investigate the relative contributions of the natural/internal climate variability and anthropogenic forcing (detection/attribution) to associated spatial trend patterns. The Arctic Ocean is chosen as the study region for this regional analysis.


Project consortium

The SLBC_cci project team is composed of following partners.

Sea level budget closure_cci consortium

European Space Agency
European Space Research Institute (ESRIN)
Dr. Jérôme Benveniste
Frascati, Italy
Contribution: launch and monitoring of this project

Technische Universität Dresden
Prof. Martin Horwath
Dresden, Germany
Scientific leader and project manager
Contribution: Ocean mass contribution / Ocean mass budget assessment

Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS)
Dr. Anny Cazenave
Toulouse, France
Contribution: Global mean sea level change / Sea level budget assessment

University of Reading
Prof. Christopher Merchant
Reading, U.K.
Steric sea level change  (contributions to this project from SSL4SLBC) University of Bremen

Prof. Ben Marzeion
Bremen, Germany
Contribution of Global Glacier
University of Zurich

Dr. Frank Paul
Zurich, Switzerland
Contribution of Global Glacier

University of Leeds
Prof. Andrew Shepherd, Centre for Polar Observation and Modelling (CPOM), School of Earth and Environment
Leeds, U.K.
Contribution of Antarctic and Greenland Ice Sheets

Technical University of Denmark / DTU Space
Prof. Rene Forsberg
Kopenhagen, Denmark
Contribution of Antarctic and Greenland Ice Sheets
Goethe-Universität Frankfurt

Prof. Petra Döll
Frankfurt/M., Germany
Contribution: Continental Hydrology
Nansen Environmental and Remote Sensing Center (NERSC)

Prof. Johnny A. Johannessen
Bergen, Norway
Contribution:Arctic Ocean

Technical University of Denmark / DTU Space
Geodesy
Dr. Ole B. Andersen
Kopenhagen, Denmark
Contribution: Arctic Ocean


Resources, data and documents

Technical reports

  • D1.1 Science Requirements Document. Accepted 2/8/2017 Revised version: 25.8.2017
  • D1.2 Science Requirements Updated and Preliminary Thoughts on Roadmap. Accepted 27.6.2018
  • D1.3 Science Roadmap for future research objectives. Accepted 18.01.2019 Revised version: 08.03.2019
  • D2.1.2 Product Description Document Description of data set and uncertainty assessment (version 0) Accepted 27/6/2017 Revised version: 5.9.2017
  • D2.3.2 Product Description Document Description of data set and uncertainty assessment (version 1) Accepted 26/10/2018 Revised version: 22.11.2018
  • D2.4.2 Product Description Document Description of data set and uncertainty assessment (version 2) Accepted: 12/03/2019 Revised version: 19.6.2019
  • D3.1 Sea Level Budget Closure Assessment Report Report 1 based on version 0 data                                                    Accepted 07/03/2018 Revised version: 07.05.2018
  • D3.2 Sea Level Budget Closure Assessment Report Report 2 based on version 1 data Accepted 28/01/2019 Revised version: 08.03.2019
  • D3.3 Sea Level Budget Closure Assessment Report Report 3 based on version 2 data Accepted 13.11.2019 Revised version: 24.11.2019
  • D4.7 Final Report Accepted 02.01.2020 Revised version: 14.02.2020

Product Description

  • D2.1.2 Product Description Document Description of data set and uncertainty assessment (version 0) Version v1.1 Accepted 27.6.2017 Revised version: 05.09.2017
  • D2.3.2 - Product Description Document Description of data set and uncertainty assessment (version 1) Version v1.2. Accepted 26.10.2018 Revised version: 22.11.2018
  • D2.4.2 - Product Description Document Description of data set and uncertainty assessment (version 2) Version v1.2 Accepted: 12.03.2019 Revised version: 19.6.2019

Data

  • D2.1.1 - Data package containing initial time series of individual components (version 0)           01.06.2017 
  • D2.2 - Data package containing sample time series of preliminary improved individual components    15.12.2017
  • D2.3.1 - Data package containing preliminary improved time series of individual components (version 1) 31.08.2018
  • D2.4.1 - Data package containing final improved time series of individual components (version 2) 14.02.2019

Publications

Ablain, M., Meyssignac, B., Zawadzki, L., Jugier, R., Ribes, A., Spada, G., Benveniste, J., Cazenave, A., and Picot, N. (2019): Uncertainty in satellite estimates of global mean sea-level changes, trend and acceleration. Earth Syst. Sci. Data, 11, 1189–1202, doi: 10.5194/essd-11-1189-2019.

Cazenave, A., Hamlington, B., Horwath, M., Barletta, V., Benveniste, J., Chambers, D., Döll, P., Hogg, A.E., Legeais, J.F., Merrifield, M., Meyssignac, B., Mitchum, G., Nerem, S., Pail, R., Palanisamy, H., Paul, F., von Schuckmann, K., Thompson, P. (2019): Observational Requirements for Long-Term Monitoring of the Global Mean Sea Level and Its Components Over the Altimetry Era. Frontiers in Marine Science, 6, 582. doi: 10.3389/fmars.2019.00582

Zemp, M., Huss, M., Thibert, E., Eckert, N., McNabb, R., Huber, J., Barandun, M., Machguth, H., Nussbaumer, S.U., Gärtner-Roer, I., Thomson, L., Paul, F., Maussion, F., Kutuzov, S., Cogley, J.G. (2019): Global glacier mass changes and their contributions to sea-level rise from 1961 to 2016. Nature 568, 382–386, doi: 10.1038/s41586-019-1071-0

Shepherd, A., Gilbert, L., Muir, A.S., Konrad, H., McMillan, M., Slater, T., Briggs, K.H., Sundal, A.V., Hogg, A.E., Engdahl, M. (2019): Trends in Antarctic Ice Sheet Elevation and Mass. Geophysical Research Letters, 46, 8174–8183, doi: 10.1029/2019GL082182

Mottram, R., Simonsen, S.B., Høyer Svendsen, S., Barletta, V.R., Sandberg Sørensen, L., Nagler, T., Wuite, J., Groh, A., Horwath, M., Rosier, J., Solgaard, A., Hvidberg, C.S., Forsberg, R. (2019): An Integrated View of Greenland Ice Sheet Mass Changes Based on Models and Satellite Observations. Remote Sensing, 11(12), 1407, doi: 10.3390/rs11121407

Martinec, Z., Klemann, V., van der Wal, W., Riva, R.E.M., Spada, G., Sun, Y., Melini, D., Kachuck, S.B., Barletta, V., Simon, K., A, G., James, T.S. (2018): A benchmark study of numerical implementations of the sea level equation in GIA modelling. Geophysical Journal International, 215, 389-414, doi: 10.1093/gji/ggy280

Rose, S.K., Andersen, O.B., Passaro, M., Ludwigsen, C.A., Schwatke, C. (2019): Arctic Ocean Sea Level Record from the Complete Radar Altimetry Era: 1991–2018. Remote Sensing, 11(14), 1672, doi: 10.3390/rs11141672

Ludwigsen, C. A., & Andersen, O. B. (2020). Contributions to Arctic Sea Level from 2003-2015. Advances in Space Researchdoi: 10.1016/j.asr.2019.12.027

Cáceres, D., Marzeion, B., Malles, J. H., Gutknecht, B., Müller Schmied, H., and Döll, P. (2020): Assessing global water mass transfers from continents to oceans over the period 1948–2016, Hydrol. Earth Syst. Sci. Discuss., 10.5194/hess-2019-664


Conference presentations

SeaLevel2017 - Regional Sea Level Changes and Coastal Impacts, 10-14 July 2017, New York, USA

Horwath M., and the SLBC_cci team Sea level budget closure: status and prospects from an integrative study within ESA's Climate Change Initiative Conference and Workshop on: Climate Impacts on Glaciers and Biosphere in Fuego-Patagonia, 14-19 July 2017, Berlin, Germany

Le Bris, Raymond, et al. Glaciers of Patagonia in 2016: A new inventory from Landsat 8 and analysis of changes IGS 2017 – Polar Ice, Polar Climate, Polar Change, 14-19 August 2017, Boulder, Colorado, USA

Paul, Frank An updated 2016 glacier inventory for central western Greenland and changes since 1985 Ocean Surface Topography Science Team Meeting,   23-27 October 2017, Miami, FL, USA

Horwath, M., and the SLBC_cci team Sea level budget closure: status and prospects from an integrative study within ESA's Climate Change Initiative AGU Fall Meeting, 11-15 December 2017, New Orleans, USA

Palanisamy, H., and the SLBC_cci team Revisiting global mean sea level budget closure: Preliminary results from an integrative study within ESA's Climate Change Initiative -Sea level Budget Closure-Climate Change Initiative

Hogg, Anna, et al. Ice shelf thickness change from 2010 to 2017

Merchant, Christopher J., et al. Global Sea Surface Temperature: A Harmonized Multi-sensor Time-series from Satellite Observations Tag der Hydrologie 2018, 22/23 March 2018, Dresden, Germany

Cáceres, Denise, et al. Closing the global sea level budget by combining multiple measurements with global-scale modeling of land water storage and glacier mass trends European Geosciences Union General Assembly 2018, 8-13 April 2018, Vienna, Austria

Horwath, M., and the SLBC_cci team Global sea level budget and ocean mass budget assessment: initial results from ESA's CCI Sea Level Budget project (PDF)

Andersen, Ole B., et al. Dynamical Coastal Topography and tide gauge unification using altimetry and GOCE

Cáceres, Denise, et al. Towards the implementation of the Open Global Glacier Model output data into the global hydrological model WaterGAP 2.2

Nilsen, Jan Even O., et al. Assessment of the Arctic Ocean sea level budget

Polar 2018, SCAR & IASC conference, 15-18 June 2018, Davos, Switzerland

Horwath, M., and the SLBC_cci team Gravimetric Mass Balance Products for the Antarctic and Greenland Ice Sheet

Groh, Andreas, et al. Separating Cryospheric and Oceanic Mass Changes in GRACE Monthly Solutions

Hogg, Anna, et al. Ice Shelf Thickness Change from 2010 to 2017

Marzeion, Ben, et al. Major 20th Century Contribution to Sea-level Rise from Uncharted Glaciers

Paul, Frank Glacier Changes in Western Greenland Derived from New Satellite and DEM Data Sea Level Futures Workshop, 2-4 July 2018, Liverpool, UK

Hogg, A., and the SLBC_cci team Global Sea Level Budget and Ocean Mass Budget Assessment: Preliminary Results From ESA's CCI Sea Level Budget Closure Project (PDF) COSPAR 2018, 42nd assembly, 14-22 July 2018, Pasadena, USA

Horwath, M., and the SLBC_cci team Global Sea Level Budget And Ocean Mass Budget Assessment: Preliminary Results From ESA’s CCI Sea Level Budget Project 25 Years of Progress in Radar Altimetry Symposium, 24-29 September 2018, Ponta Delgada, Portugal

Cazenave, A., Horwath, M., and the SLBC_cci team Global Sea Level Budget Assessment: Preliminary Results From ESA’s CCI Sea Level Budget Closure Project AGU Fall Meeting,  10-14 December 2018, Washington, D.C., USA

Horwath M., and the SLBC_cci team Assessing the global sea level budget and its uncertainties: progress from ESA's CCI Sea Level Budget Closure project

Ludwigsen, CA; Andersen, OB; Rose, SK; Khan, SA; Knudsen, P. Spatial analysis of the arctic sea level budget

Knudsen, P., Andersen O.B., Ludwigsen C.A., Rose, S.K., and Passaro, M. Arctic sea level. Satellite and in-situ observations for more than 25 years European Geosciences Union General Assembly,   7-12 April 2019, Vienna, Austria

Horwath, M., and the SLBC_cci team Global sea level budget and ocean mass budget assessment: initial results from ESA's CCI Sea Level Budget Closure project

Cáceres, D. et al. Assessing recent water mass losses from the continents by integrating output data from a global glacier model into a global hydrological model

Rose, S.K., Andersen, O.B., Ludwigsen, C.A., and Passaro, M. Arctic sea level study. Satellite and in-situ observations for more than 25 years

Malles, J.-H., and Marzeion, B. Multi-Objective Optimization of a Global Glacier Mass Balance Model ESA 2019 Living Planet Symposium, 13-17 May 2019, Milan, Italy

Horwath, M., and the SLBC_cci team The Global Sea Level Budget and its Uncertainties: Results from ESA's Sea Level Budget Closure CCI Project

Rose S.K., Andersen O.B., Passaro  M., Benveniste J. 25 years of sea level records from the Arctic Ocean using radar altimetry

Raj, R.P. , et al. Assessment of the Arctic Ocean sea-level budget: ESA's CCI Sea Level Budget Closure 27th IUGG General Assembly,  8-18 July 2019, Montréal, Québec, Canada

Horwath, M. and the Sea Level Budget Closure CCI Group The Global Sea Level Budget and its Uncertainties: Results from ESA's Sea Level Budget Closure CCI Project

O. Andersen, S.K. Rose, T. Veng Global and Arctic sea level change from ESA satellites OceanObs’19, 16-20 September 2019, Honolulu, Hawaii, USA

Horwath, M. et al. The Global Sea Level Budget and its Uncertainties: Results from ESA's Sea Level Budget Closure CCI Project AGU Fall Meeting,  9-13 December 2019, San Francisco, USA

Sea Level Budget Closure CCI Group Global Sea Level Budget and Ocean Mass Budget, with Focus on New Data Products and Uncertainty Characterization.

Müller Schmied, H. Simulating global freshwater resources with WaterGAP 2.2d


Contact us / support

For any questions concerning the project, please contact Martin Horwath (scientific lead of the project) or Jérôme Benvenise who launched and monitors the project.

Prof. Martin Horwath
Institut für Planetare Geodäsie
Technische Universität Dresden
01062 Dresden
Germany

Tel: +49 351 463-34652
Fax: +49 351 463-37063
Email: martin.horwath[at]​tu-dresden.de

Project Technical officer: 
Dr. Jérôme Benveniste
European Space Agency
European Space Research Institute (ESRIN)
Email: Jerome.benveniste[at]esa.int