Antarctic ice mass fluxes from satellite observations

Lead Research Organisation: University of Bristol
Department Name: Geographical Sciences

Abstract

The Antarctic ice sheet is the largest freshwater store on Earth by an order of magnitude and contains enough ice to increase global sea level by ~65 m. Changes in the input and output of ice (the mass balance) have profound implications for sea level, ocean circulation and inferences concerning the stability of the ice mass. The mass balance of the ice sheet is controlled by both short term and long term processes related to changes in snowfall and ice dynamics. To understand how the ice sheet is behaving now and to be able to predict how it will behave in the future we need to be able to quantify and separate the processes responsible for the trends in mass balance. Some recent research using satellite measurements of elevation change suggests that increased snowfall may be contributing to a positive mass balance for large sectors of the East Antarctic ice sheet (EAIS). This conclusion, however, is not universally accepted and the results do not account for processes related to ice dynamics close to the margins of the ice sheet. Other recent studies, using different satellite data, suggest that overall, the ice sheet is losing a large amount of mass and that the EAIS is roughly in balance. To solve the open and crucial question of whether the EAIS is losing or gaining mass and to better understand the mass balance trends for the whole ice sheet, we will obtain accurate, regional-scale mass balance measurements with well constrained error budgets. In this project, in collaboration with US and Dutch partners, we will determine the mass balance of individual drainage basins covering ~85% of the ice sheet and the larger floating ice shelves using a combination of new and existing satellite observations and atmospheric modelling. In particular, we aim to determine conclusively whether the East Antarctic Ice Sheet is a net source or sink of ocean mass. We also aim to investigate the relative importance of trends in snowfall and ice dynamics in the mass budget of the ice sheet.

Publications

10 25 50
 
Description Resolved regional mass loss trends over Antarctica for multiple epochs for the first time. Derived ice thickness estimate for all ice shelves across Antarctica. These data were used to determine the partition between bottom melting and iceberg calving for the first time
Exploitation Route The data from the project were used to determine the partition between bottom melting and iceberg calving for the first time

They have been used in numerous other studies on Antarctic ice shelves and were incorporated in a new bedmap for Antarctica.
Sectors Environment

 
Description They were cited in the IPCC AR5 and have been used extensively by others working on Antarctic research and were incorporated in a new bedmap for Antarctica.
First Year Of Impact 2008
Sector Environment
Impact Types Societal

 
Description consultation by chief scientific adviser
Geographic Reach National 
Policy Influence Type Participation in advisory committee
 
Description Framework 7 Integrated award
Amount € 9,900,000 (EUR)
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 03/2009 
End 11/2013
 
Description Collaboration with Bert Wouters (Universiteit Utrecht) 
Organisation Utrecht University
Country Netherlands 
Sector Academic/University 
PI Contribution Joint development of CryoSat processing and combining with GRACE
Collaborator Contribution Joint development of CryoSat processing and combining with GRACE
Impact The collaboration has resulted in the following papers relevant to RCUK grants: -Wouters, B., J. L. Bamber, M. R. van den Broeke, J. T. M. Lenaerts and I. Sasgen (2013). "Limits in detecting acceleration of ice sheet mass loss due to climate variability." Nature Geosci advance online publication. - Martin Espanol, A., Zammit Mangion, A., Clarke, P. J., Flament, T., Helm, V., King, M. A., Luthcke, S.B, Petrie, E., Rémy, F. Schön, N., Wouters, B. and Bamber, J. (2016). Spatial and temporal Antarctic Ice Sheet mass trends, glacio-isostatic adjustment, and surface processes from a joint inversion of satellite altimeter, gravity, and GPS data. Journal of Geophysical Research: Earth Surface, 121(2), 182-200. DOI:10.1002/2015JF003550 - Wouters, B., Martin-Español, A., Helm, V., Flament, T., van Wessem, J. M., Ligtenberg, S.R.M., Van den Broeke, M.R. and Bamber, J.L. "Dynamic thinning of glaciers on the Southern Antarctic Peninsula." Science 348, no. 6237 (2015): 899-903. - Sasgen, I., Martín-Español, A., Horvath, A., Klemann, V., Petrie, E.J., Wouters, B., Horwath, M., Pail, R., Bamber, J.L., Clarke, P.J. and Konrad, H., 2017. Joint inversion estimate of regional glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE Project REGINA). Geophysical Journal International, 211(3), pp.1534-1553.
Start Year 2011
 
Description Collaboration with Ian Joughin (University of Washington) 
Organisation University of Washington
Country United States 
Sector Academic/University 
PI Contribution Joint programmes of research
Collaborator Contribution Provision of data and expert advice on data issues
Impact The collaboration has resulted in the following papers relevant to RCUK grants post 2006: -Joughin, I., S. Tulaczyk, J. L. Bamber, D. Blankenship, J. W. Holt, T. Scambos and D. G. Vaughan (2009). "Basal conditions for Pine Island and Thwaites Glaciers, West Antarctica, determined using satellite and airborne data." J. Glaciology 55(190): 245-257. -Hurkmans, R. T. W. L., J. L. Bamber, L. S. Sørensen, I. R. Joughin, C. H. Davis and W. B. Krabill (2012). "Spatiotemporal interpolation of elevation changes derived from satellite altimetry for Jakobshavn Isbræ, Greenland." J. Geophys. Res. 117(F3): F03001. - Hurkmans, R. T. W. L., Bamber, J. L., Davis, C. H., Joughin, I. R., Khvorostovsky, K. S., Smith, B. S., and Schoen, N.: Time-evolving mass loss of the Greenland Ice Sheet from satellite altimetry, The Cryosphere, 8, 1725-1740, https://doi.org/10.5194/tc-8-1725-2014, 2014.
 
Description Expert advice to the European Environment Agency 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The EEA workshop fed into their quinquennial review of the state of the climate system. It also resulted in a widely cited paper.

see above.
Year(s) Of Engagement Activity 2010
 
Description Princes Teaching Institute 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The teachers follow up on my presentation with a number of activities and ideas for classroom teaching.

Teachers express an increased awareness of the polar regions in global processes
Year(s) Of Engagement Activity 2013,2014,2015,2016,2017
URL http://www.princes-ti.org.uk/