Processes, drivers, Prediction: modeling the History and Evolution of Thwaites (PROPHET)

PROPHET is a modelling project intended to reduce uncertainty in near-future projections of the evolution of Thwaites Glacier. This will be achieved by improving the representation of several key processes that are not currently characterised well in large scale ice-flow models, and by determining the relative importance of different external drivers of change. Using coupled ice-ocean models, predictions will be made of the future ice loss from Thwaites Glacier and its contribution to sea level rise.

Processes such as calving, ice damage and basal melt are not well represented in current models. Improving ice-flow models is essential for accurately forecasting future ice loss from Thwaites Glacier.

The PROPHET team will use three different ice-flow models—ISSM, Úa and STREAMICE—to better characterize these key processes. Each ice-flow model will be coupled with the ocean model MITgcm for simulations linking Thwaites Glacier to the Amundsen Sea. The use of three separate models will encapsulate a wider range of uncertainty and help to identify any areas where a particular model may need more improvement. Once the processes are better understood, the improved models will be validated by comparing observational data collected from 1992 onwards to simulated outputs covering the same time range.

The final step will be to investigate future change in Thwaites Glacier and the surrounding area on 100- to 500-year timescales, using the newly improved models with their better representation of important physical processes. The models will be forced by different ocean-warming scenarios, with multiple simulations to reflect the range of uncertainty in model parameterisation. This will produce future ice-loss and sea-level projections with reduced uncertainty compared to those currently available.

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De Rydt, J., and G.H. Gudmundsson. 2016. Coupled ice shelf‐ocean modeling and complex grounding line retreat from a seabed ridge. Journal of Geophysical Research: Earth Surface 121(5): 865-880.

De Rydt, J., Reese, R., Paolo, F. S., and Gudmundsson, G. H. 2021. Drivers of Pine Island Glacier speed-up between 1996 and 2016. The Cryosphere 15, 113–132.

Dias dos Santos, T., M. Morlighem, and D. Brinkerhoff. 2022. A new vertically integrated MOno-Layer Higher-Order (MOLHO) ice flow model. The Cryosphere 16, 179–195.

dos Santos, T. D., M. Morlighem, and H. Seroussi. 2021. Assessment of numerical schemes for transient, finite-element ice flow models using ISSM v4.18. Geosci. Model Dev., 14: 2545–2573.

Thiago Dias dos Santos, Jowan M. Barnes, Daniel N. Goldberg, G. Hilmar Gudmundsson, Mathieu Morlighem. 2021. Drivers of Change of Thwaites Glacier, West Antarctica, Between 1995 and 2015. Geophysical Research Letters 48:20 e2021GL093102.

Favier, L., G. Durand, S.L. Cornford, G.H. Gudmundsson, O. Gagliardini, F. Gillet-Chaulet, T. Zwinger, A.J. Payne, and A.M. Le Brocq. 2014. Retreat of Pine Island Glacier controlled by marine ice-sheet instability. Nature Climate Change 4(2): 117-121.

Goldberg, D.N., K. Snow, P. Holland, J.R. Jordan, J.M. Campin, P. Heimbach, R. Arthern, and A. Jenkins. 2018. Representing grounding line migration in synchronous coupling between a marine ice sheet model and a z-coordinate ocean model. Ocean Modelling 125: 45-60.

Goldberg, D.N., P. Heimbach, I. Joughin, and B. Smith. 2015. Committed retreat of Smith, Pope, and Kohler Glaciers over the next 30 years inferred by transient model calibration. The Cryosphere 9: 2429-2446.

Goldberg, D. N., T. A. Smith, S. HK Narayanan, et al.  2020. Bathymetric influences on Antarctic ice-shelf melt rates. ESS Open Archive: October 22, 2020.

Gudmundsson, G.H., F.S. Paolo, S. Adusumilli, and H.A. Fricker. 2019. Instantaneous Antarctic ice‐sheet mass loss driven by thinning ice shelves. Geophysical Research Letters 46, 13,903–13,909.

Malczyk, G., N. Gourmelen, D. Goldberg, J. Wuite, and T. Nagler. 2020. Repeat Subglacial Lake Drainage and Filling Beneath Thwaites Glacier. Geophysical Research Letters, 47:23, e2020GL089658.

Morlighem, M., Rignot, E., Binder, T. et al. 2020. Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet. Nat. Geosci. 13, 132–137.

Morlighem, M., D. Goldberg, T. Dias dos Santos, J. Lee, and M. Sagebaum. 2021. Mapping the Sensitivity of the Amundsen Sea Embayment to Changes in External Forcings Using Automatic Differentiation. Geophysical Research Letters 48:23 e2021GL095440.

Rignot, E., J. Mouginot, M. Morlighem, H. Seroussi, and B. Scheuchl. 2014. Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith, and Kohler glaciers, West Antarctica, from 1992 to 2011. Geophysical Research Letters 41: 3502-3509.

Rosier, S. H. R., R. Reese, J. F. Donges, J. De Rydt, G. H. Gudmundsson, and R. Winkelmann. 2021. The tipping points and early warning indicators for Pine Island Glacier, West Antarctica. The Cryosphere, 15, 1501–1516, 2021.

Rosier, S. H. R., C. Y. S. Bull, W. L. Woo, and G. H. Gudmundsson. 2023. Predicting ocean-induced ice-shelf melt rates using deep learning. The Cryosphere, 17, 499–518.

Seroussi, H., M. Morlighem, E. Rignot, J. Mouginot, E. Larour, M. Schodlok, and A. Khazendar. 2014. Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years. The Cryosphere 8: 1699-1710.
Grant Number
NSF PLR 1739031, NERC NE/S006745/1, NERC NE/S006796/1

Principal Investigators

Hilmar Gudmundsson

Mathieu Morlighem

Co-Investigators

Indrani Das

Daniel Goldberg

Noel Gourmelen

Brent Minchew

Team Members

Jowan Barnes

Thiago Dias dos Santos

Martin Wearing

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