References

Solid Earth

1869-9529

Copernicus Publications

Göttingen, Germany

10.5194/se-5-569-2014

Future Antarctic bed topography and its implications for ice sheet dynamics

Adhikari

¹ ² Ivins

E. R.

https://orcid.org/0000-0003-0148-357X

¹ Larour

¹ Seroussi

https://orcid.org/0000-0001-9201-1644

¹ Morlighem

https://orcid.org/0000-0001-5219-1310

³ Nowicki

⁴

Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA

Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA

Department of Earth System Science, University of California – Irvine, 3200 Croul Hall, Irvine, CA 92697, USA

Code 615, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA

30 06 2014

5 1 569 584

2014

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

This article is available from https://se.copernicus.org/articles/5/569/2014/se-5-569-2014.html

The full text article is available as a PDF file from https://se.copernicus.org/articles/5/569/2014/se-5-569-2014.pdf

The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) has generally been losing its mass since the Last Glacial Maximum. In a sustained warming climate, the AIS is predicted to retreat at a greater pace, primarily via melting beneath the ice shelves. We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS. We find that past loading is relatively less important than future loading for the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years AD 2100 and 2500, respectively, and that the East Antarctic Ice Sheet is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay will approach roughly 45 mm yr<sup>−1</sup> in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is generally associated with the flattening of reverse bed slope, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote stability in marine portions of the ice sheet in the future.

References 1

Bamber, J. L. and Aspinall, W. P.: An expert judgement assessment of future sea level rise from the ice sheets, Nature Clim. Change, 3, 424–427, 2013.

Bamber, J. L., Gomez-Dans, J. L., and Griggs, J. A.: A new 1 km digital elevation model of the Antarctic derived from combined satellite radar and laser data - Part 1: Data and methods, The Cryosphere, 3, 101–111, <a href="http://www.the-cryosphere.net/3/101/2009/">http://www.the-cryosphere.net/3/101/2009/</a>, 2009.

Bindschadler, R., Nowicki, S., Abe-Ouchi, A., Aschwanden, A., Choi, H., Fastook, J., Granzow, G., Greve, R., Gutowski, G., Herzfeld, U., Jackson, C., Johnson, J., Khroulev, C., Levermann, A., Lipscomb, W., Martin, M., Morlighem, M., Parizek, B., Pollard, D., Price, S., Ren, D., Saito, F., Sato, T., Seddik, H., Seroussi, H., Takahashi, F., Walker, R., and Wang, W.: Ice-Sheet Model Sensitivities to Environmental Forcing and Their Use in Projecting Future Sea-Level (The SeaRISE Project), J. Glaciol., 59, 195–224, <a href="http://dx.doi.org/10.3189/2013JoG12J125">https://doi.org/10.3189/2013JoG12J125</a>, 2013.

Borstad, C. P., Khazendar, A., Larour, E., Morlighem, M., Rignot, E., Schodlok, M. P., and Seroussi, H.: A damage mechanics assessment of the Larsen B ice shelf prior to collapse: Toward a physically-based calving law, Geophys. Res. Lett., 39, 1–5, <a href="http://dx.doi.org/10.1029/2012GL053317">https://doi.org/10.1029/2012GL053317</a>, 2012.

Clark, P. U., Dyke, A. S., Shakun, J. D., Carlson, A. E., Clark, J., Wohlfarth, B., Mitrovica, J. X., Hostetler, S. W., and Marshall McCabe, A.: The last glacial maximum, Science, 5941, 710–714, <a href="http://dx.doi.org/10.1126/science.1172873">https://doi.org/10.1126/science.1172873</a>, 2009.

Conway, H., Hall, B. L., Denton, G. H., Gades, A. M., and Waddington, E. D.: Past and future grounding-line retreat of the West Antarctic Ice Sheet, Science, 286, 280–283, <a href="http://dx.doi.org/10.1126/science.286.5438.280">https://doi.org/10.1126/science.286.5438.280</a>, 1999.

Cook, C. P., van de Flierdt, T., Williams, T., Hemming, S. R., Iwai, M., Kobayashi, M., Jimenez-Espejo, F. J., Escutia, C., González, J. J., Khim, B.-K., McKay, R. M., Passchier, S., Bohaty, S. M., Riesselman, C. R., Tauxe, L., Sugisaki, S., Lopez Galindo, A., Patterson, M. O., Sangiorgi, F., Pierce, E. L., Brinkhuis, H., Klaus, A., Fehr, A., Bendle, J. A. P., Bijl, P. K., A. Carr, S., Dunbar, R. B., Flores, J. A., Hayden, T. G., Katsuki, K., Kong, G. S., Nakai, M., Olney, M. P., Pekar, S. F., Pross, J., Röhl, U., Sakai, T., Shrivastava, P. K., Stickley, C. E., Tuo, S., Welsh, K., and Yamane, M.: Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth, Nat. Geosci., 6, 765–769, <a href="http://dx.doi.org/10.1038/ngeo1889">https://doi.org/10.1038/ngeo1889</a>, 2013.

Cuffey, K. and Paterson, W. S. B.: The Physics of Glaciers, 4th Edition, Elsevier, 2010.

Depoorter, M. A., Bamber, J. L., Griggs, J. A., Lenaerts, J. T. M., Ligtenberg, S. R. M., van den Broeke, M. R., and Moholdt, G.: Calving fluxes and basal melt rates of Antarctic ice shelves, Nature, 502, 89–92, <a href="http://dx.doi.org/10.1038/nature12567">https://doi.org/10.1038/nature12567</a>, 2013.

Dziewonski, A. M. and Anderson, D. L.: Preliminary reference Earth model, Phys. Earth Planet. Inter., 25, 297–356, 1981.

Favier, L., Gagliardini, O., Durand, G., and Zwinger, T.: A three-dimensional full Stokes model of the grounding line dynamics: effect of a pinning point beneath the ice shelf, The Cryosphere, 6, 101–112, <a href="http://dx.doi.org/10.5194/tc-6-101-2012">https://doi.org/10.5194/tc-6-101-2012</a>, 2012.

Favier, V., Agosta, C., Parouty, S., Durand, G., Delaygue, G., Gallee, H., Drouet, A., Trouvilliez, A., and Krinner, G.: An updated and quality controlled surface mass balance dataset for Antarctica, The Cryosphere, 7, 583–597, <a href="http://dx.doi.org/10.5194/tc-7-583-2013">https://doi.org/10.5194/tc-7-583-2013</a>, 2013.

Fjeldskaar, W.: The amplitude and decay of the glacial forebulge in Fennoscandia, Norsk Geologisk Tidsskrift, 74, 2–8, 1994.

Glen, J.: The creep of polycrystalline ice, Proc. R. Soc. A, 228, 519–538, 1955.

Gomez, N., Mitrovica, J. X., Huybers, P., and Clark, P. U.: Sea level as a stabilizing factor for marine-ice-sheet grounding lines, Nat. Geosci., 3, 850–853, <a href="http://dx.doi.org/10.1038/ngeo1012">https://doi.org/10.1038/ngeo1012</a>, 2010.

Gomez, N., Pollard, D., and Mitrovica, J.: A 3-D coupled ice sheet - sea level model applied to Antarctica through the last 40 ky, Earth Planet. Sci. Lett., 384, 88–99, 2013.

Greve, R.: A continuum-mechanical formulation for shallow polythermal ice sheets, Phil. Trans R. Soc. A, 355, 921–974, 1997.

Groh, A., Ewert, H., Scheinert, M., Fritsche, M., Rülke, A., Richter, A., Rosenau, R., and Dietrich, R.: An investigation of glacial isostatic adjustment over the Amundsen Sea Sector, West Antarctica, Glob. Planet. Change, 98–99, 45–53, 2012.

Hughes, T., Sargent, A., and Fastook, J.: Ice-bed coupling beneath and beyond ice streams: Byrd Glacier, Antarctica, J. Geophys. Res., 116, 1–17, <a href="http://dx.doi.org/10.1029/2010JF001896">https://doi.org/10.1029/2010JF001896</a>, 2011.

IPCC-AR4: Fourth Assessment Report: Climate Change 2007: The AR4 Synthesis Report, Geneva: IPCC, <a href="http://www.ipcc.ch/ipccreports/ar4-wg1.htm">http://www.ipcc.ch/ipccreports/ar4-wg1.htm</a>, 2007.

Ivins, E. R. and James, T. S.: S}imple models for late Holocene and present-day Patagonian glacier fluctuations and predictions of a geodetically detectable isostatic response, Geophys. J. {Int., 138, 601–624, <a href="http://dx.doi.org/10.1046/j.1365-246x.1999.00899.x">https://doi.org/10.1046/j.1365-246x.1999.00899.x</a>, 1999.

Ivins, E. R. and James, T. S.: Antarctic glacial isostatic adjustment: a new assessment, Antarct. Sci., 17, 541–553, 2005.

Ivins, E. R., James, T. S., Wahr, J., O. Schrama, E. J., Landerer, F. W., and Simon, K. M.: Antarctic contribution to sea level rise observed by GRACE with improved GIA correction, J. Geophys. Res., 118, 3126–3141, <a href="http://dx.doi.org/10.1002/jgrb.50208">https://doi.org/10.1002/jgrb.50208</a>, 2013.

James, T. S. and Ivins, E. R.: Predictions of A}ntarctic crustal motions driven by present-day ice sheet evolution and by isostatic memory of the {Last Glacial Maximum, J. Geophys. Res., 103, 4993–5017, <a href="http://dx.doi.org/10.1029/97JB03539">https://doi.org/10.1029/97JB03539</a>, 1998.

Katz, R. and Worster, M.: Stability of ice-sheet grounding lines, Proc. R. Soc. A, 466, 1597–1620, <a href="http://dx.doi.org/10.1098/rspa.2009.0434">https://doi.org/10.1098/rspa.2009.0434</a>, 2010.

Kessler, M. A., Anderson, R. S., and Briner, J. P.: Fjord insertion into continental margins driven by topographic steering of ice, Nat. Geosci., 1, 365–369, <a href="http://dx.doi.org/10.1038/ngeo201">https://doi.org/10.1038/ngeo201</a>, 2008.

Konrad, H., Thoma, M., Sasgen, I., Klemann, V., Grosfeld, K., Barbi, D., and Martinec, Z.: The deformational response of a viscoelastic solid Earth model coupled to a thermomechanical ice sheet model, Survey in Geophysics, pp. 1–18, <a href="http://dx.doi.org/10.1007/s10712-013-9257-8">https://doi.org/10.1007/s10712-013-9257-8</a>, 2013.

Larour, E., Schiermeier, J., Rignot, E., Seroussi, H., Morlighem, M., and Paden, J.: Sensitivity A}nalysis of Pine Island Glacier ice flow using {ISSM and DAKOTA, J. Geophys. Res., 117, F02009, 1–16, <a href="http://dx.doi.org/10.1029/2011JF002146">https://doi.org/10.1029/2011JF002146</a>, 2012a.

Larour, E., Seroussi, H., Morlighem, M., and Rignot, E.: Continental scale, high order, high spatial resolution, ice sheet modeling using the Ice Sheet System Model (ISSM), J. Geophys. Res., 117, F01022, 1–20, <a href="http://dx.doi.org/10.1029/2011JF002140">https://doi.org/10.1029/2011JF002140</a>, 2012b.

Le Meur, E. and Huybrechts, P.: A comparison of different ways of dealing with isostasy: examples from modelling the Antarctic ice sheet during the last glacial cycle, Ann. Glaciol., 23, 309–317, 1996.

Le Meur, E. and Huybrechts, P.: A model computation of the temporal changes of surface gravity and geoidal signal induced by the evolving Greenland ice sheet, Geophys. J. Int., 145, 835–849, 2001.

Lingle, C. and Clark, J.: A numerical model of interactions between a marine ice sheet and the solid earth: application to a west Antarctic ice stream, J. Geophys. Res., 90, 1100–1114, 1985.

MacAyeal, D.: A tutorial on the use of control methods in ice-sheet modeling, J. Glaciol., 39, 91–98, 1993.

McConnell, R. K. J.: Isostatic adjustment in a layered Earth, J. Geophys. Res., 70, 5171–5188, <a href="http://dx.doi.org/10.1029/JZ070i020p05171">https://doi.org/10.1029/JZ070i020p05171</a>, 1965.

Morlighem, M., Rignot, E., Seroussi, H., Larour, E., Ben Dhia, H., and Aubry, D.: Spatial patterns of basal drag inferred using control methods from a full-Stokes and simpler models for Pine Island Glacier, West Antarctica, Geophys. Res. Lett., 37, L14502, 1–6, <a href="http://dx.doi.org/10.1029/2010GL043853">https://doi.org/10.1029/2010GL043853</a>, 2010.

Morlighem, M., Seroussi, H., Larour, E., and Rignot, E.: Inversion of basal friction in Antarctica using exact and incomplete adjoints of a higher-order model, J. Geophys. Res., 118, 1746–1753, <a href="http://dx.doi.org/10.1002/jgrf.20125">https://doi.org/10.1002/jgrf.20125</a>, 2013.

Naish, T., Powell, R., Levy, R., Wilson, G., Scherer, R., Talarico, F., Krissek, L., Niessen, F., Pompilio, M., Wilson, T., Carter, L., DeConto, R., Huybers, P., McKay, R., Pollard, D., Ross, J., Winter, D., Barrett, P., Browne, G., Cody, R., Cowan, E., Crampton, J., Dunbar, G., Dunbar, N., Florindo, F., Gebhardt, C., Graham, I., Hannah, M., Hansaraj, D., Harwood, D., Helling, D., Henrys, S., Hinnov, L., Kuhn, G., Kyle, P., Läufer, A., Maffioli, P., Magens, D., Mandernack, K., McIntosh, W., Millan, C., Morin, C., Ohneiser, C., Paulsen, T., Persico, D., Raine, I., Reed, J., Riesselmann, C., Sagnotti, L., Schmitt, D., Sjunneskog, C., Strong, P., Taviani, M., Vogel, S., Wilch, T., and Williams, T.: Obliquity-paced pliocene West Antarctic ice sheet oscillations, Nature, 458, 322–329, <a href="http://dx.doi.org/10.1038/nature07867">https://doi.org/10.1038/nature07867</a>, 2009.

Nowicki, S., Bindschadler, R., Abe-Ouchi, A., Aschwanden, A., Bueler, E., Choi, H., Fastook, J., Granzow, G., Greve, R., Gutowski, G., Herzfeld, U., Jackson, C., Johnson, J., Khroulev, C., Larour, E., Levermann, A., Lipscomb, W., Martin, M., Morlighem, M., Parizek, B., Pollard, D., Price, S., Ren, D., Rignot, E., Saito, F., Sato, T., Seddik, H., Seroussi, H., Takahashi, K., Walker, R., and Wang, W.: Insights into spatial sensitivities of ice mass response to environmental change from the SeaRISE ice sheet modeling project I}: {Antarctica, J. Geophys. Res., 118, 1–23, <a href="http://dx.doi.org/10.1002/jgrf.20081">https://doi.org/10.1002/jgrf.20081</a>, 2013.

Pattyn, F.: A new three-dimensional higher-order thermomechanical ice sheet model: Basic sensitivity, ice stream development, and ice flow across subglacial lakes, J. Geophys. Res., 108, 1–15, <a href="http://dx.doi.org/10.1029/2002JB002329">https://doi.org/10.1029/2002JB002329</a>, 2003.

Peltier, W.: Global glacial isostasy and the surface of the ice-age Earth: The 699 ICE-5G (VM2) model and GRACE, Annu. Rev. Earth Planet. Sci., 32, 111–149, 2004.

Pollard, D. and DeConto, R.: Modelling West Antarctica ice sheet growth and collapse through the past five million years, Nature, Letters 458, 329–332, <a href="http://www.nature.com/nature/journal/v458/n7236/abs/nature078% 09.html">http://www.nature.com/nature/journal/v458/n7236/abs/nature078

Pritchard, H. D., Ligtenberg, S. R. M., Fricker, H. A., Vaughan, D. G., van den Broeke, M. R., and Padman, L.: Antarctic ice-sheet loss driven by basal melting of ice shelves, Nature, 484, 502–505, <a href="http://dx.doi.org/10.1038/nature10968">https://doi.org/10.1038/nature10968</a>, 2012.

Raymo, M., Mitrovica, J. X., O'Leary, M., DeConto, R., and Hearty, P.: Departures from eustasy in Pliocene sea-level records, Nature Geosci., 4, 328 – 332, <a href="http://dx.doi.org/http://dx.doi.org/10.1038/ngeo1118">https://doi.org/http://dx.doi.org/10.1038/ngeo1118</a>, 2011.

Rignot, E., Mouginot, J., and Scheuchl, B.: Ice Flow of the Antarctic Ice Sheet, Science, 333, 1427–1430, <a href="http://dx.doi.org/10.1126/science.1208336">https://doi.org/10.1126/science.1208336</a>, 2011.

Rignot, E., Jacobs, S., Mouginot, J., and Scheuchl, B.: Ice shelf melting around Antarctica, Science, <a href="http://dx.doi.org/10.1126/science.1235798">https://doi.org/10.1126/science.1235798</a>, 2013.

Schoof, C.: Ice sheet grounding line dynamics: Steady states, stability, and hysteresis, J. Geophys. Res., 112, 1–19, <a href="http://dx.doi.org/10.1029/2006JF000664">https://doi.org/10.1029/2006JF000664</a>, 2007.

Seroussi, H., Ben Dhia, H., Morlighem, M., Rignot, E., Larour, E., and Aubry, D.: Coupling ice flow models of varying order of complexity with the Tiling Method, J. Glaciol., 58 (210), 776–786, <a href="http://dx.doi.org/10.3189/2012JoG11J195">https://doi.org/10.3189/2012JoG11J195</a>, 2012.

Siegert, M., Ross, N., Corr, H., Kingslake, J., and Hindmarsh, R.: Late Holocene ice-flow reconfiguration in the Weddell Sea sector of West Antarctica, Quaternary Science Rev., 78, 98–107, 2013.

Smith, A. M., Bentley, C. R., Bingham, R. G., and Jordan, T. A.: Rapid subglacial erosion beneath Pine Island Glacier, West Antarctica, Geophys. Res. Lett., 39, L12501, <a href="http://dx.doi.org/10.1029/2012GL051651">https://doi.org/10.1029/2012GL051651</a>, 2012.

Thomas, I. D., King, M. A., Bentley, M. J., Whitehouse, P. L., Penna, N. T., Williams, S. D. P., Riva, R. E. M., Lavallée, D. A., Clarke, P. J., King, E. C., Hindmarsh, R. C. A., and Koivula, H.: Widespread low rates of Antarctic glacial isostatic adjustment revealed by GPS observations, Geophys. Res. Lett., 38, L22302, <a href="http://dx.doi.org/10.1029/2011GL049277">https://doi.org/10.1029/2011GL049277</a>, 2011.

Thomas, R.: Thickening of the Ross Ice Shelf and equilibrium stat of the West Antarctic Ice Sheet, Nature, 259, 180–183, 1976.

van Vuuren, D., Edmonds, J., Kainuma, M., Riahi, K., Thomson, A., Hibbard, K., Hurtt, G., Kram, T., Krey, V., Lamarque, J., Masui, T., Meinshausen, M., Nakicenovic, N., Smith, S., and Rose, S.: The representative concentration pathways: an overview, Clim. Dynam., 109, 5–31, 2011.

Vaughan, D. and Arthern, R.: Why is it hard to predict the future of ice sheets?, Science, 315, 1503–1504, 2007.

Verfaillie, D., Fily, M., Le Meur, E., Magand, O., Jourdain, B., Arnaud, L., and Favier, V.: Snow accumulation variability derived from radar and firn core data along a 600 km transect in Adelie Land, East Antarctic plateau, The Cryosphere, 6, 1345–1358, <a href="http://dx.doi.org/10.5194/tc-6-1345-2012">https://doi.org/10.5194/tc-6-1345-2012</a>, 2012.

Walker, R. T., Holland, D. M., Parizek, B. R., Alley, R. B., Nowicki, S. M. J., and Jenkins, A.: Efficient flowline simulations of ice shelf-ocean interactions: sensitivity studies with a fully coupled model, J. Phys. Oceanogr., 43, 2200–2210, <a href="http://dx.doi.org/10.1175/JPO-D-13-037.1">https://doi.org/10.1175/JPO-D-13-037.1</a>, 2013.

Wang, W., Li, J., and Zwally, J.: Dynamic inland propagation of thinning due to ice loss at the margins of the Greenland ice sheet, J. Glaciol., 58, 734–740, 2012.

Weertman, J.: Stability of the junction of an ice sheet and an ice shelf, J. Glaciol., 13(67), 3–11, 1974.

Whitehouse, P., Bentley, M. J., and Brocq, A. M. L.: A deglacial model for Antarctica: geological constraints and glaciological modelling as a basis for a new model of Antarctic glacial isostatic adjustment, Quaternary Sci. Rev., 32, 1–24, 2012.

Winkelmann, R., Martin, M. A., Haseloff, M., Albrecht, T., Bueler, E., Khroulev, C., and Levermann, A.: The Potsdam Parallel Ice Sheet Model (PISM-PIK) - Part 1: Model description, Cryosphere, 5, 715–726, <a href="http://dx.doi.org/10.5194/tc-5-715-2011">https://doi.org/10.5194/tc-5-715-2011</a>, 2011.

Winkelmann, R., Levermann, A., Martin, M. A., and Frieler, K.: Increased future ice discharge from Antarctica owing to higher snowfall, Nature, 492, 239–242, <a href="http://dx.doi.org/10.1038/nature11616">https://doi.org/10.1038/nature11616</a>, 2012.

Wolf, D.: The normal modes of a uniform, incompressible Maxwell half-space, J. Geophys., 56, 106–117, <a href="http://elib.uni-stuttgart.de/opus/volltexte/2010/5078">http://elib.uni-stuttgart.de/opus/volltexte/2010/5078</a>, 1985.