In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica

Indrani Das; Mathieu Morlighem; Jowan M. Barnes; G. Hilmar Gudmundsson; Daniel Goldberg; thiago Santos

doi:10.1029/2022GL098910

In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica

Indrani Das, Mathieu Morlighem, Jowan M. Barnes, G. Hilmar Gudmundsson, Daniel Goldberg, thiago Santos

School of Geosciences

Research output: Contribution to journal › Article › peer-review

Abstract / Description of output

Numerical ice sheet models use sliding laws to connect basal shear stress and ice velocity to simulate ice sliding. A sliding-law parameter β2 is used to control Weertman’s sliding law in numerical ice sheet models. Basal reflectivity derived from ice-penetrating radar also provides information about frozen or thawed conditions underneath glaciers. To assess whether basal reflectivity can be used to constrain β2, we carry out statistical experiments between two recently published datasets: β2 inferred from three numerical ice sheet models (ISSM, Úa and STREAMICE) and airborne radar-derived relative basal reflectivity from the AGASEA-BBAS mission over Thwaites Glacier. Our results show no robust correlation between the β2–reflectivity pair. Pearson’s correlation coefficient, a test of linearity, ranges from -0.26 to -0.38. Spearman’s correlation coefficient, which does not require a linear assumption, is also modest (~ -0.35). We conclude that β2 and basal reflectivity underneath Thwaites Glacier do not infer similar basal conditions.

Original language	English
Article number	e2022GL098910
Journal	Journal of Geophysical Research
Volume	50
Issue number	10
Early online date	26 May 2023
DOIs	https://doi.org/10.1029/2022GL098910
Publication status	Published - 28 May 2023

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10.1029/2022GL098910Licence: Creative Commons: Attribution Non-Commercial (CC-BY-NC)

Geophysical Research Letters - 2023 - Das - In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman (1)
© 2023 The Authors
Final published version, 2.07 MBLicence: Creative Commons: Attribution Non-Commercial (CC-BY-NC)

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL098910Licence: Creative Commons: Attribution Non-Commercial (CC-BY-NC)

QuORUM: QUantifying and Reducing Uncertainty in Multi-Decadal Projection of Ice Sheet-Sea Level Contribution
Maddison, J.
NERC
1/01/20 → 31/12/22
Project: Research
NSFPLR-NERC: Processes, drivers, predictions: Modeling the response of Thwaites Glacier over the next century using ice/ocean coupled models
Goldberg, D. & Gourmelen, N.
NERC
1/09/18 → 31/08/23
Project: Research

Cite this

Das, I., Morlighem, M., Barnes, J. M., Gudmundsson, G. H., Goldberg, D., & Santos, T. (2023). In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica. Journal of Geophysical Research, 50(10), Article e2022GL098910. https://doi.org/10.1029/2022GL098910

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title = "In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica",

abstract = "Numerical ice sheet models use sliding laws to connect basal shear stress and ice velocity to simulate ice sliding. A sliding-law parameter β2 is used to control Weertman{\textquoteright}s sliding law in numerical ice sheet models. Basal reflectivity derived from ice-penetrating radar also provides information about frozen or thawed conditions underneath glaciers. To assess whether basal reflectivity can be used to constrain β2, we carry out statistical experiments between two recently published datasets: β2 inferred from three numerical ice sheet models (ISSM, {\'U}a and STREAMICE) and airborne radar-derived relative basal reflectivity from the AGASEA-BBAS mission over Thwaites Glacier. Our results show no robust correlation between the β2–reflectivity pair. Pearson{\textquoteright}s correlation coefficient, a test of linearity, ranges from -0.26 to -0.38. Spearman{\textquoteright}s correlation coefficient, which does not require a linear assumption, is also modest (~ -0.35). We conclude that β2 and basal reflectivity underneath Thwaites Glacier do not infer similar basal conditions.",

author = "Indrani Das and Mathieu Morlighem and Barnes, {Jowan M.} and Gudmundsson, {G. Hilmar} and Daniel Goldberg and thiago Santos",

note = "Funding Information: The authors declare no real or perceived financial conflicts of interests. Two anonymous reviewers greatly improved the manuscript. This work is from the PROPHET project, a component of the International Thwaites Glacier Collaboration (ITGC), ITGC Contribution No. ITGC‐069. Support from National Science Foundation (NSF: Grant 1739031) and Natural Environment Research Council (NERC: NE/S006745/1, NE/S006796/1, NE/T001607/1); NASA Cryosphere 80NSSC21K0747, and the Vetlessen Foundation. The authors also acknowledge helpful discussions with Dustin Schroeder, Alberto Malinverno, Joseph MacGregor, Doug MacAyeal, Riley Culberg, Winnie Chu, John Paden, Brent Minchew, Christian Schoof, Elena Kosh, and Robert Jacobel. Publisher Copyright: {\textcopyright} 2023 The Authors.",

year = "2023",

month = may,

day = "28",

doi = "10.1029/2022GL098910",

language = "English",

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Das, I, Morlighem, M, Barnes, JM, Gudmundsson, GH, Goldberg, D & Santos, T 2023, 'In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica', Journal of Geophysical Research, vol. 50, no. 10, e2022GL098910. https://doi.org/10.1029/2022GL098910

In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica. / Das, Indrani; Morlighem, Mathieu; Barnes, Jowan M. et al.
In: Journal of Geophysical Research, Vol. 50, No. 10, e2022GL098910, 28.05.2023.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica

AU - Das, Indrani

AU - Morlighem, Mathieu

AU - Barnes, Jowan M.

AU - Gudmundsson, G. Hilmar

AU - Goldberg, Daniel

AU - Santos, thiago

N1 - Funding Information: The authors declare no real or perceived financial conflicts of interests. Two anonymous reviewers greatly improved the manuscript. This work is from the PROPHET project, a component of the International Thwaites Glacier Collaboration (ITGC), ITGC Contribution No. ITGC‐069. Support from National Science Foundation (NSF: Grant 1739031) and Natural Environment Research Council (NERC: NE/S006745/1, NE/S006796/1, NE/T001607/1); NASA Cryosphere 80NSSC21K0747, and the Vetlessen Foundation. The authors also acknowledge helpful discussions with Dustin Schroeder, Alberto Malinverno, Joseph MacGregor, Doug MacAyeal, Riley Culberg, Winnie Chu, John Paden, Brent Minchew, Christian Schoof, Elena Kosh, and Robert Jacobel. Publisher Copyright: © 2023 The Authors.

PY - 2023/5/28

Y1 - 2023/5/28

N2 - Numerical ice sheet models use sliding laws to connect basal shear stress and ice velocity to simulate ice sliding. A sliding-law parameter β2 is used to control Weertman’s sliding law in numerical ice sheet models. Basal reflectivity derived from ice-penetrating radar also provides information about frozen or thawed conditions underneath glaciers. To assess whether basal reflectivity can be used to constrain β2, we carry out statistical experiments between two recently published datasets: β2 inferred from three numerical ice sheet models (ISSM, Úa and STREAMICE) and airborne radar-derived relative basal reflectivity from the AGASEA-BBAS mission over Thwaites Glacier. Our results show no robust correlation between the β2–reflectivity pair. Pearson’s correlation coefficient, a test of linearity, ranges from -0.26 to -0.38. Spearman’s correlation coefficient, which does not require a linear assumption, is also modest (~ -0.35). We conclude that β2 and basal reflectivity underneath Thwaites Glacier do not infer similar basal conditions.

AB - Numerical ice sheet models use sliding laws to connect basal shear stress and ice velocity to simulate ice sliding. A sliding-law parameter β2 is used to control Weertman’s sliding law in numerical ice sheet models. Basal reflectivity derived from ice-penetrating radar also provides information about frozen or thawed conditions underneath glaciers. To assess whether basal reflectivity can be used to constrain β2, we carry out statistical experiments between two recently published datasets: β2 inferred from three numerical ice sheet models (ISSM, Úa and STREAMICE) and airborne radar-derived relative basal reflectivity from the AGASEA-BBAS mission over Thwaites Glacier. Our results show no robust correlation between the β2–reflectivity pair. Pearson’s correlation coefficient, a test of linearity, ranges from -0.26 to -0.38. Spearman’s correlation coefficient, which does not require a linear assumption, is also modest (~ -0.35). We conclude that β2 and basal reflectivity underneath Thwaites Glacier do not infer similar basal conditions.

U2 - 10.1029/2022GL098910

DO - 10.1029/2022GL098910

M3 - Article

SN - 0148-0227

VL - 50

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

IS - 10

M1 - e2022GL098910

ER -

In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman Sliding-Law Parameter and Airborne Radar-Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica

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QuORUM: QUantifying and Reducing Uncertainty in Multi-Decadal Projection of Ice Sheet-Sea Level Contribution

NSFPLR-NERC: Processes, drivers, predictions: Modeling the response of Thwaites Glacier over the next century using ice/ocean coupled models

Cite this