Slope estimation influences on ice thickness inversion models: a case study for Monte Tronador glaciers, North Patagonian Andes

ZORZUT, VALENTINA; RUIZ, LUCAS; RIVERA, ANDRES; PITTE, PIERRE; VILLALBA, RICARDO; MEDRZYCKA, DOROTA

JOURNAL OF GLACIOLOGY

INT GLACIOL SOC

Año: 2020 p. 1 - 10

0022-1430

Glacier ice thickness is crucial to quantifying water resources in mountain regions, and is anessential input for ice-flow models. Using a surface velocity inversion method, we combine icethickness measurements with detailed surface elevation and velocity data, and derive ice thicknessand volume estimates for the Monte Tronador glaciers, North Patagonian Andes. We test thedependence of the inversion model on surface slope by resampling glacier slopes using variablesmoothing filter sizes of 16?720 m. While total glacier volumes do not differ considerably, icethickness estimates show higher variability depending on filter size. Smaller (larger) smoothingscales give thinner (thicker) ice and higher (lower) noise in ice thickness distribution. A filtersize of 300 m, equivalent to four times the mean ice thickness, produces a noise-free thicknessdistribution with an accuracy of 35m. We estimate the volume of the Monte Tronador glaciersat 4.8 ± 2 km3 with a mean ice thickness of 75 m. Comparison of our results with earlier regionaland global assessments shows that the quality of glacier inventories is a significant source of discrepancy. We show that including surface slope as an input parameter increases the accuracy ofice thickness distribution estimates.