Resolving Antarctic ice mass TrEndS (RATES)

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

Abstract

The Antarctic ice sheet is the largest on the planet by a factor 10. It holds enough ice to raise global sea level by ~65 m. Small changes in the balance between losses and gains (the mass balance) can have, therefore, profound implications for sea level, ocean circulation and our understanding of the stability of the ice mass. Local variations in mass balance may be driven by short or long term changes in ice dynamics that may or may not be related to recent climatic change. They may also be due to trends in snowfall. There is now a general consensus that the ice sheet is losing mass but the range of estimates and uncertainties are still, in most cases, larger than the signal. To solve the open question of what the time evolving mass change is, we propose combining satellite observations, climate modelling and physical constraints to solve for the independent and uncorrelated errors that have hampered previous approaches.

Sea level rise (SLR) since 1992 has averaged around 3.2 mm/yr, ~ twice the mean for the 20th Century. The cause is uncertain, but it is clear that a significant component is due to increased losses from both Greenland and Antarctica. Recent advances in regional climate modelling and analysis of gravity anomalies from the GRACE satellites have greatly improved our knowledge of both the magnitude and origin of mass losses from Greenland. Unfortunately, this is not the case for Antarctica for a range of reasons. The aim of this project is to address this shortcoming using a similar, but more comprehensive, approach to the one we used to improve our understanding of changes in Greenland. To do this, we must employ additional data and methods because i) the uncertainty in post glacial rebound for the West Antarctic Ice Sheet , in particular, is of a similar magnitude to the signal (unlike Greenland), ii) errors in observed and modelled variables are generally larger because of the paucity of in-situ data sets in, and around, Antarctica, and iii) observations in time and space are poorer for most of the ice sheet and, in particular, the areas showing the greatest change.

Planned Impact

There are three broad categories of user groups who will benefit from the results and activities of the project in addition to scientists working directly on ice sheets and sea level rise. These are i) climate scientists, ii) the climate change policy community and iii) the general public, (including schools).

i) Climate scientists (outside of the field of research)
This community includes, for example, members of the IPCC AR5 team. We will regularly inform the coordinating lead authors for Chapter 4 (Observations: cryosphere), Chapter 5: (Information from Paleoclimate archives) and Chapter 13 (Sea Level Change) of progress and results from the project. JLB is a review editor for Ch 4 and will be attending the next author meetings in July 2011, April 2012 and Jan 2013. We are also intimately linked to the paleo sea level and GIA communities, through the PAGES programme PALSEA (http://eis.bris.ac.uk/~glyms/working_group.html) while MAK is Chair of an EU COST Action which involves leading groups in 20+ European countries working on the problem of improving models of GIA and its geodetic observation. He is also closely involved with the global POLENET community. These two networks allow him to ensure the results of the new bedrock surface velocity field are widely promoted, providing an invaluable dataset for forward and inverse modelling of GIA and constraining deglaciation history by other groups.

ii) Policy community.
We have direct links with the following organizations who have benefited from previous related research and who will benefit from this work. The list below is not meant to be exhaustive but to illustrate the type of beneficiary in this category with an indication of how they might benefit:
UK Met Office & DECC: coordinating the AVOID programme (a DECC/DEFRA funded project, http://www.avoid.uk.net/)
Public Interest Research Centre (http://www.pirc.info/) provides climate policy documents for the public and UNFCC.
Scientific Committee on Antarctic Research: coordinating role for Antarctic science.
UN Environment Programme: provides information about climate change and sea level rise to general public and educational establishments.
European Environment Agency: delivers policy information to the EC and member states.

These and other organisations will benefit from this project through gaining a clear understanding of how, and to what extent, the Antarctic ice sheet has contributed to sea level over the last two decades, the limitations in our current understanding, the implications of our findings and recommendations for future foci related to this topic. We have provide similar information to most of these organizations in the past and have good links. We will send them regular updates during the project, the final Project Report and invite them to attend the end of project workshop. Past experience indicates that this category of end user has greatly benefited from a strong interaction and involvement with the experts doing the work.

iii) The general public. Antarctic research has huge potential for capturing the public imagination and engaging students at both primary and secondary level in issues related to climate change, environmental policy, glaciology and polar processes. We know this from first hand experience. JLB and MAT currently undertake talks to local schools and will continue to do this for this project. As a RCUK Academic Fellow MAK is funded to undertake schools outreach, e.g., lecturing 6th form students at Emmanuel College, Gateshead, on sea level change. JLB was until recently head of undergraduate admissions for Geography at UoB and, in this capacity, developed a number of widening participation activities which he is still involved with.

Publications

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Martin-Español A (2017) Constraining the mass balance of East Antarctica MASS BALANCE OF EAST ANTARCTICA in Geophysical Research Letters

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Fang Wang (2015) Accuracy and Performance of CryoSat-2 SARIn Mode Data Over Antarctica in IEEE Geoscience and Remote Sensing Letters

 
Description Partitioned the role of bottom melting and iceberg calving in mass loss from Antarctica.
Exploitation Route The methodology and software has been made publicly available and the approach could be used in a wide range of problems in geosciences. Full documentation and examples have been provided on github.
Sectors Education,Environment

URL https://sites.google.com/site/antarcticmassbalance/
 
Description Our results were presented at COP21 in Paris.
First Year Of Impact 2015
Sector Education,Environment,Government, Democracy and Justice
Impact Types Societal

 
Description ERC Advanced Grant
Amount € 2,397,430 (EUR)
Funding ID 694188 
Organisation European Research Council (ERC) 
Sector Public
Country European Union (EU)
Start 08/2016 
End 07/2021
 
Description STSE
Amount € 150,000 (EUR)
Organisation European Space Agency 
Sector Public
Country France
Start 01/2013 
End 10/2014
 
Title MVST 
Description An R-Software package for multi-variate spatio-temporal modelling 
Type Of Material Data analysis technique 
Year Produced 2017 
Provided To Others? Yes  
Impact Essential to the outcomes of the RATES project and subsequently developed further in the ERC-funded GlobalMass grant 
URL https://github.com/andrewzm/MVST
 
Title Spatiotemporal mass balance trends for the Antarctic Ice Sheet, 2003-2013 
Description The Antarctic mass trends have been collated from a combination of different remote sensing datasets. These are trends of yearly elevation changes over Antarctica for the period 2003-2013 due to the different geophysical processes driving changes in Antarctica: ice dynamics, surface mass balance and glacio-isostatic adjustment (GIA). Net trends can be easily calculated by adding together surface and ice dynamics trends. 20 km gridded datasets have been produced for each process, per year (except the GIA solution which is time-invariant). To convert elevation to mass trends, we also provide the density fields for surface (SMB) and GIA processes used in Martin-Espanol et al (2016). These can be directly multiplied by the dh/dt. To convert dh/dt from ice dynamics, simply multiply by the density of ice. Mass smb = dh/dt smb * d surf Mass ice = dh/dt ice * d ice (not provided) Mass gia = dh/dt gia * d surf 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
Impact Used by various research groups to provide ice mass balance and sea level rise for Antarctica 
URL https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/00916
 
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 Frederique Remy (LEGOS) 
Organisation The Lego Group
PI Contribution Collaboration on problem in geosciences (ENVISat data)
Collaborator Contribution Provision of data and expert advice on data issues
Impact The collaboration has resulted in the following papers: - Schoen, N. W ., Zammit-Mangion, A., Rougier, J. C., Flament, T., Rémy, F., Luthcke, S., & Bamber, J. L. (2015). Simultaneous solution for mass trends on the West Antarctic Ice Sheet. Cryosphere, 9(2), 805-819. DOI:10.5194/tc-9-805-2015 - 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
Start Year 2010
 
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 Collaboration with Ingo Sasgen (AWI) 
Organisation Alfred-Wegener Institute for Polar and Marine Research
Country Germany 
Sector Public 
PI Contribution Joint programme of research
Collaborator Contribution Expert advice on geodesy and GPS analyses, calculation of vertical land motion and PI on joint project
Impact Joint publications: Sasgen, I., M. van den Broeke, J. L. Bamber, E. Rignot, L. S. Sorensen, B. Wouters, Z. Martinec, I. Velicogna, and S. B. Simonsen (2012), Timing and origin of recent regional ice-mass loss in Greenland, Earth and Planetary Science Letters, 333, 293-303, doi:10.1016/j.epsl.2012.03.033. Sasgen, I., H. Konrad, E. R. Ivins, M. R. Van den Broeke, J. L. Bamber, Z. Martinec, and V. Klemann (2013), Antarctic ice-mass balance 2003 to 2012: regional reanalysis of GRACE satellite gravimetry measurements with improved estimate of glacial-isostatic adjustment based on GPS uplift rates, The Cryosphere, 7(5), 1499-1512, doi:10.5194/tc-7-1499-2013. Sasgen, I., et al. (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), 1534-1553, doi:10.1093/gji/ggx368.
Start Year 2011
 
Description Collaboration with Matt King (UTAS) 
Organisation University of Tasmania
Country Australia 
Sector Academic/University 
PI Contribution Joint programme of research
Collaborator Contribution Expert advice on geodesy and GPS analyses
Impact The collaboration has resulted in the following papers: - 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 - Martin Espanol, A., King, M., Zammit Mangion, A., Andrews, S., Moore, P., & Bamber, J. (2016). An assessment of forward and inverse GIA solutions for Antarctica. Journal of Geophysical Research: Solid Earth, 121(9), 6947-6965. DOI: 10.1002/2016JB013154
Start Year 2011
 
Description Collaboration with Scott Luthcke (NASA GSFC) 
Organisation National Aeronautics and Space Administration (NASA)
Department Goddard Space Flight Center
Country United States 
Sector Public 
PI Contribution Collaboration on problem in geosciences (GRACE data)
Collaborator Contribution Provision of data and expert advice on data issues
Impact The collaboration has resulted in the following papers: - Schoen, N. W ., Zammit-Mangion, A., Rougier, J. C., Flament, T., Rémy, F., Luthcke, S., & Bamber, J. L. (2015). Simultaneous solution for mass trends on the West Antarctic Ice Sheet. Cryosphere, 9(2), 805-819. DOI:10.5194/tc-9-805-2015 - 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
Start Year 2010
 
Title Bayesian Hierarchical model for environmental sciences 
Description S/w for solving for multifactor processes from a suite of point and distributed spatio-temporal data sets. 
Type Of Technology Software 
Year Produced 2014 
Open Source License? Yes  
Impact too early 
URL https://github.com/andrewzm/MVST