Parameter sensitivity analysis of dynamic ice sheet models-Numerical computations
Pith reviewed 2026-05-25 19:42 UTC · model grok-4.3
The pith
Adjoint equations of the stress and height equations supply weights to quantify how perturbations in friction and base topography affect surface velocity and height in ice sheet models.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The sensitivity to the perturbations of the velocity and the height at the surface is quantified by solving the adjoint equations of the stress and height equations providing weights for the perturbed data. The adjoint equations are solved numerically and the sensitivity is computed in several examples in two dimensions. Comparisons are made with analytical solutions to simplified problems for both the full Stokes model and the shallow shelf approximation applied to stationary and dynamic ice sheets.
What carries the argument
The adjoint equations of the stress and height equations, solved numerically to produce weights that measure the effect of changes in friction coefficient and base topography on surface observations.
Load-bearing premise
The adjoint equations remain accurate representations of the sensitivity when they are discretized and solved numerically for the full dynamic ice sheet models.
What would settle it
Direct finite-difference recomputation of surface velocity and height after small changes in friction or topography, compared against the adjoint-derived weights on the same two-dimensional mesh, would disagree if the discretized adjoints fail to capture the true sensitivity.
Figures
read the original abstract
The friction coefficient and the base topography of a stationary and a dynamic ice sheet are perturbed in two models for the ice: the full Stokes equations and the shallow shelf approximation. The sensitivity to the perturbations of the velocity and the height at the surface is quantified by solving the adjoint equations of the stress and the height equations providing weights for the perturbed data. The adjoint equations are solved numerically and the sensitivity is computed in several examples in two dimensions. Comparisons are made with analytical solutions to simplified problems.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript develops adjoint-based methods to quantify the sensitivity of surface velocity and height to perturbations in the friction coefficient and base topography for both stationary and time-dependent ice-sheet models. It derives adjoint equations from the full Stokes and shallow-shelf approximation (SSA) systems, solves them numerically, and computes sensitivities in several 2D examples, with comparisons restricted to analytical solutions of simplified problems.
Significance. If the numerical adjoint solutions are shown to be accurate for the dynamic cases, the work would supply an efficient, derivative-based tool for sensitivity analysis that avoids repeated forward solves, with direct relevance to data assimilation and uncertainty quantification in glaciology. The 2D demonstrations and analytic comparisons for simplified cases are a useful starting point, but the absence of cross-validation for the full dynamic systems limits the immediate applicability of the reported weights.
major comments (1)
- [Abstract] Abstract: the central claim that the numerically solved adjoint equations of the stress and height equations 'provide weights for the perturbed data' for dynamic models rests on the unverified assumption that discretization and solver errors do not invalidate the sensitivities; the only reported checks are analytic comparisons for simplified (non-dynamic) problems, with no mention of finite-difference perturbation tests on the same meshes or manufactured-solution verification for the coupled time-dependent Stokes/SSA systems.
Simulated Author's Rebuttal
We thank the referee for the careful and constructive review. The point raised about verification of the adjoint sensitivities for the dynamic cases is well taken, and we address it directly below with a commitment to strengthen the manuscript.
read point-by-point responses
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Referee: [Abstract] Abstract: the central claim that the numerically solved adjoint equations of the stress and height equations 'provide weights for the perturbed data' for dynamic models rests on the unverified assumption that discretization and solver errors do not invalidate the sensitivities; the only reported checks are analytic comparisons for simplified (non-dynamic) problems, with no mention of finite-difference perturbation tests on the same meshes or manufactured-solution verification for the coupled time-dependent Stokes/SSA systems.
Authors: We agree that the analytic comparisons in the manuscript are limited to simplified problems and that the dynamic Stokes and SSA cases lack explicit cross-validation such as finite-difference perturbation tests or manufactured-solution checks on the same meshes. The numerical results for the time-dependent models are obtained by solving the derived adjoint equations, but without those additional tests the claim that the computed sensitivities provide reliable weights rests on the consistency of the discretization rather than direct verification. To address this, we will add finite-difference perturbation tests for the dynamic cases in the revised manuscript, performed on the same meshes and with the same solvers used for the adjoint computations. This will allow direct comparison of the adjoint-derived sensitivities against finite-difference approximations for the full time-dependent systems. revision: yes
Circularity Check
No circularity: adjoint sensitivity follows standard derivation from governing PDEs
full rationale
The paper derives adjoint equations directly from the stress and height equations of the full Stokes and SSA models to compute surface sensitivities to perturbations in friction coefficient and base topography. This is a standard, non-circular application of adjoint methods for PDE sensitivity analysis, with numerical solutions compared to analytical results on simplified problems. No self-definitional reductions, fitted inputs renamed as predictions, or load-bearing self-citations are present in the abstract or described method. The derivation chain is self-contained and independent of the target sensitivities.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Adjoint equations derived from the stress and height equations correctly quantify sensitivities to friction and topography perturbations.
Lean theorems connected to this paper
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IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
The sensitivity to the perturbations of the velocity and the height at the surface is quantified by solving the adjoint equations of the stress and the height equations providing weights for the perturbed data.
-
IndisputableMonolith/Foundation/RealityFromDistinction.leanreality_from_one_distinction unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
The adjoint equations are solved numerically and the sensitivity is computed in several examples in two dimensions.
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
P.: Virtual bubbles and G alerkin-least-squares type methods ( Ga
Baiocchi, C., Brezzi, F., and Franca, L. P.: Virtual bubbles and G alerkin-least-squares type methods ( Ga. LS ), Comp. Meth. Appl. Mech. Eng., 105, 125--141, 1993
work page 1993
-
[2]
Glaciology, 63, 854--866, 2017
Brondex, J., Gagliardini, O., Gillet-Chaulet, F., and Durand, G.: Sensitivity of grounding line dynamics to the choice of the friction law, J. Glaciology, 63, 854--866, 2017
work page 2017
-
[3]
Bulthuis, K., Arnst, M., Sun, S., and Pattyn, F.: Uncertainty quantification of the multi-centennial response of the A ntarctic ice sheet to climate change, Cryosphere, 13, 1349--1380, 2019
work page 2019
-
[4]
Cheng , G. and L \"o tstedt , P.: Parameter sensitivity analysis of dynamic ice sheet models , arXiv e-prints, arXiv:1906.08197, 2019
-
[5]
Durand, G., Gagliardini, O., Favier, L., Zwinger, T., and Le Meur , E.: Impact of bedrock description on modeling ice sheet dynamics, Geophys. Res. Lett., 38, L20\,501, 2011
work page 2011
-
[6]
Model Dev., 6, 1299--1318, 2013
Gagliardini, O., Zwinger, T., Gillet-Chaulet, F., Durand, G., Favier, L., de Fleurian, B., Greve, R., Malinen, M., Mart \'i n, C., R back, P., Ruokolainen, J., Sacchettini, M., Sch \"a fer, M., Seddik, H., and Thies, J.: Capabilities and performance of E lmer/ I ce, a new generation ice-sheet model, Geosci. Model Dev., 6, 1299--1318, 2013
work page 2013
-
[7]
Gillet-Chaulet, F., Gagliardini, O., Seddik, H., Nodet, M., Durand, G., Ritz, C., Zwinger, T., Greve, R., and Vaughan, D. G.: Greenland ice sheet contribution to sea-level rise from a new-generation ice-sheet model, Cryosphere, 6, 1561--1576, 2012
work page 2012
-
[8]
Gillet-Chaulet, F., Durand, G., Gagliardini, O., Mosbeux, C., Mouginot, J., R \'e my, F., and Ritz, C.: Assimilation of surface velocities acquired between 1996 and 2010 to constrain the form of the basal friction law under P ine I sland G lacier, Geophys. Res. Lett., 43, 10\,311--10\,321, 2016
work page 1996
-
[9]
Gladstone, R. M., Warner, R. C., Galton-Fenzi, B. K., Gagliardini, O., Zwinger, T., and Greve, R.: M arine ice sheet model performance depends on basal sliding physics and sub-shelf melting, Cryosphere, 11, 319--329, 2017
work page 2017
-
[10]
Golub, G. H. and Loan, C. F. V.: Matrix Computations, Johns Hopkins University Press, Baltimore, 2nd edn., 1989
work page 1989
-
[11]
Greve, R. and Blatter, H.: D ynamics of I ce S heets and G laciers, A dvances in G eophysical and E nvironmental M echanics and M athematics (AGEM ^2 ), Springer, Berlin, 2009
work page 2009
-
[12]
H.: Transmission of basal variability to glacier surface, J
Gudmundsson, G. H.: Transmission of basal variability to glacier surface, J. Geophys. Res., 108, 2003
work page 2003
-
[13]
Isaac, T., Petra, N., Stadler, G., and Ghattas, O.: Scalable and efficient algorithms for the propagation of uncertainty from data through inference to prediction for large-scale problems with application to flow of the A ntarctic ice sheet, J. Comput. Phys., 296, 348--368, 2015
work page 2015
-
[14]
Jay-Allemand, M., Gillet-Chaulet, F., Gagliardini, O., and Nodet, M.: Investigating changes in basal conditions of V ariegated G lacier prior to and during its 1982-1983 surge, Cryosphere, 5, 659--672, 2011
work page 1982
-
[15]
Kyrke-Smith, T. M., Gudmundsson, G. H., and Farrell, P. E.: Relevance of detail in basal topography for basal slipperiness inversions: a case study on P ine I sland G lacier, A ntarctica, Frontiers Earth Sci., 6, 33, 2018
work page 2018
-
[16]
Larour, E., Utke, J., Csatho, B., Schenk, A., Seroussi, H., Morlighem, M., Rignot, E., Schlegel, N., and Khazendar, A.: Inferred basal friction and surface mass balance of the N ortheast G reenland I ce S tream using data assimilation of ICESat ( I ce C loud and land E levation S atellite) surface altimetry and ISSM ( I ce S heet S ystem M odel), Cryosphe...
work page 2014
-
[17]
Leguy, G. R., Asay-Davis, X. S., and Lipscomb, W. H.: Parameterization of basal friction near grounding lines in a one-dimensional ice sheet model, Cryosphere, 8, 1239--1259, 2014
work page 2014
-
[18]
MacAyeal, D. R.: Large-scale ice flow over a viscous basal sediment: T heory and application to I ce S tream B , A ntarctica., J. Geophys. Res., 94, 4071--4078, 1989
work page 1989
-
[19]
R.: A tutorial on the use of control methods in ice sheet modeling, J
MacAyeal, D. R.: A tutorial on the use of control methods in ice sheet modeling, J. Glaciol., 39, 91--98, 1993
work page 1993
-
[20]
Martin, N. and Monnier, J.: Adjoint accuracy for the full S tokes ice flow model: limits to the transmission of basal friction variability to the surface, Cryosphere, 8, 721--741, 2014
work page 2014
-
[21]
Morlighem, M., Seroussi, H., Larour, E., and Rignot, E.: Inversion of basal friction in A ntarctica using exact and incomplete adjoints of a high-order model, J. Geophys. Res.: Earth Surf., 118, 1--8, 2013
work page 2013
-
[22]
Mosbeux, C., Gillet-Chaulet, F., and Gagliardini, O.: Comparison of adjoint and nudging methods to initialise ice sheet model basal conditions, Geosci. Model. Dev., 9, 2549--2562, 2016
work page 2016
-
[23]
Pattyn, F., Schoof, C., Perichon, L., Hindmarsh, R. C. A., Bueler, E., de Fleurian, B., Durand, G., Gagliardini, O., Gladstone, R., Goldberg, D., Gudmundsson, G. H., Huybrechts, P., Lee, V., Nick, F. M., Payne, A. J., Pollard, D., Rybak, O., Saito, F., and Vieli, A.: R esults of the M arine I ce S heet M odel I ntercomparison P roject, MISMIP , Cryosphere...
work page 2012
-
[24]
Pelt van Pelt , W. J. J., Oerlemans, J., Reijmer, C. H., Pettersson, R., Pohjola, V. A., Isaksson, E., and Divine, D.: An iterative inverse method to estimate basal topography and initialize ice flow models, Cryosphere, 7, 987--1006, 2013
work page 2013
-
[25]
Petra, N., Zhu, H., Stadler, G., Hughes, T. J. R., and Ghattas, O.: An inexact G auss- N ewton method for inversion of basal sliding and rheology parameters in a nonlinear S tokes ice sheet model, J. Glaciol., 58, 889--903, 2012
work page 2012
-
[26]
Schannwell, C., Drews, R., Ehlers, T. A., Eisen, O., Mayer, C., and Gillet-Chaulet, F.: Kinematic response of ice-rise divides to changes in oceanic and atmospheric forcing, Cryosphere Discuss., 2019
work page 2019
-
[27]
Schlegel, N.-J., Seroussi, H., Schodlok, M. P., Larour, E. Y., Boening, C., Limonadi, D., Watkins, M. M., Morlighem, M., and van den Broeke, M. R.: Exploration of Antarctic Ice Sheet 100-year contribution to sea level rise and associated model uncertainties using the ISSM framework, Cryosphere, 12, 3511--3534, 2018
work page 2018
-
[28]
Schoof, C.: Ice-sheet acceleration driven by melt supply variability, Nature, 468, 803--806, 2010
work page 2010
-
[29]
Seddik, H., Greve, R., Sakakibara, D., Tsutaki, S., Minowa, M., and Sugiyama, S.: Response of the flow dynamics of B owdoin G lacier, northwestern G reenland, to basal lubrication and tidal forcing, J. Glaciol., pp. 1--14, 2019
work page 2019
-
[30]
Sergienko, O. and Hindmarsh, R. C. A.: Regular patterns in frictional resistance of ice-stream beds seen by surface data inversion, Science, 342, 1086--1089, 2013
work page 2013
-
[31]
Shannon, S. R., Payne, A. J., Bartholomew, I. D., van den Broeke, M. R., Edwards, T. L., Fettweis, X., Gagliardini, O., Gillet-Chaulet, F., Goelzer, H., Hoffman, M. J., Huybrechts, P., Mair, D. W. F., Nienow, P. W., Perego, M., Price, S. F., Smeets, C. J. P. P., Sole, A. J., van de Wal, R. S. W., and Zwinger, T.: Enhanced basal lubrication and the contrib...
work page 2013
-
[32]
C.: Uncertainty Quantification
Smith, R. C.: Uncertainty Quantification. Theory, Implementation, and Applications, Society for Industrial and Applied Mathematics, Philadelphia, 2014
work page 2014
-
[33]
Sole, A. J., Mair, D. W. F., Nienow, P. W., Bartholomew, I. D., King, I. D., Burke, M. A., and Joughin, I.: Seasonal speedup of a G reenland marine-terminating outlet glacier forced by surface melt-induced changes in subglacial hydrology, J. Geophys. Res., 116, F03\,014, 2011
work page 2011
-
[34]
Sun, S., Cornford, S. L., Liu, Y., and Moore, J. C.: Dynamic response of A ntarctic ice shelves to bedrock uncertainty, Cryosphere, 8, 1561--1576, 2014
work page 2014
-
[35]
Tsai, V. C., Stewart, A. L., and Thompson, A. F.: Marine ice-sheet profiles and stability under Coulomb basal conditions, Journal of Glaciology, 61, 205--215, 2015
work page 2015
-
[36]
Vallot, D., Pettersson, R., Luckman, A., Benn, D. I., Zwinger, T., van Pelt, W. J. J., Kohler, J., Sch \"a fer, M., Claremar, B., and Hulton, N. R. J.: Basal dynamics of K ronebreen, a fast-flowing tidewater glacier in S valbard: non-local spatio-temporal response to water input, J. Glaciol., 11, 179--190, 2017
work page 2017
-
[37]
Weertman, J.: On the sliding of glaciers, J. Glaciol., 3, 33--38, 1957
work page 1957
discussion (0)
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