1. In the Quest of a Parametric Relation Between Ice Sheet Model Inferred Weertman's Sliding‐Law Parameter and Airborne Radar‐Derived Basal Reflectivity Underneath Thwaites Glacier, Antarctica.
- Author
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Das, Indrani, Morlighem, Mathieu, Barnes, Jowan, Gudmundsson, G. Hilmar, Goldberg, Daniel, and Dias dos Santos, Thiago
- Subjects
ICE sheets ,SUBGLACIAL lakes ,STATISTICAL correlation ,GROUND penetrating radar ,PEARSON correlation (Statistics) - 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'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 (TG). Our results show no robust correlation between the β2–relative 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 relative basal reflectivity underneath TG do not infer similar basal conditions. Plain Language Summary: Ice sheet models use equations called sliding laws to simulate how fast or slow ice can flow over the bed of a glacier. One such sliding law is Weertman's sliding law, which is widely used by numerical ice sheet models. A parameter called β2 is used in Weertman's sliding law to match the observed velocity. Another parameter called basal reflectivity, derived from airborne ice penetrating radar data, is widely used to identify whether the bed underneath a glacier is frozen or thawed. Frozen or thawed conditions impact how fast a glacier can slide over its bed. Here, we try to find statistical correlations between β2 and basal reflectivity over Thwaites Glacier (TG), West Antarctica. Our results show that the correlation values are not robust, which suggests that β2 and basal reflectivity do not identify similar conditions at the bed underneath TG. Key Points: Correlation experiments are carried out between Weertman's sliding‐law parameter β2 and radar‐derived relative basal reflectivityThe correlations between β2 and relative basal reflectivity are low, suggesting that they do not identify similar conditions at the bedThe correlations do not improve with any value of the sliding exponent m between 3 and 20 [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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