Ice thickness and bed elevation of the Northern and Southern Patagonian Icefields

RIVERA, A.; ZAMORA, R.; DE FLEURIAN, B.; KIRCHNER, D.; RIGNOT, E.; MOUGINOT, J.; LENZANO, G.; GIM, Y.; MILLAN, R.; MARTINEAU, V.; URIBE, J.; LI, X.

GEOPHYSICAL RESEARCH LETTERS

AMER GEOPHYSICAL UNION

Año: 2019

0094-8276

The Northern and Southern Patagonian Icefields (NPI, SPI) are the largest ice masses in the Southern Hemisphere outside Antarctica, but their ice volume and bed topography are largely unknown. Here, we combine airborne gravity data collected in 2012 and 2016, with WISE and CECs radar sounder data from 2014 and 2015 to map bed elevation and ice thickness in great detail. We perform a three dimensional inversion of the gravity field constrained by radar-derived thickness, ice boundary, and fjord bathymetry to infer bed elevation at 500-m spacing, with a precision of about 150 m. We detect deep glacial valleys with ice thickness exceeding 1,400 m and sectors below sea level on the western branch of Glaciar Pio XI, Occidental, between San Rafael and Colonia, and near31 Fitz Roy. We calculate an ice volume of 4,756±787 km3 for NPI and SPI, or 40 times32 the volume of the Alps