First surface velocity maps for glaciers of Monte Tronador, North Patagonian Andes, derived from sequential Pléiades satellite images

RUIZ, L.; BERTHIER E.; MASIOKAS, M.; PITTE, P.; VILLALBA, RICARDO.

JOURNAL OF GLACIOLOGY

INT GLACIOL SOC

Lugar: London; Año: 2015 vol. 61 p. 908 - 922

0022-1430

We apply cross-correlation to Pléiades satelliteimages to generate accurate, high-resolution monthly surface velocity maps of MonteTronador glaciers between March and June 2012. Measured surface displacementscover periods as short as 19 days and with a precision of ca. 0.58 m (11 m a-1).These glaciers follow a radial flow pattern, with maximum surface speeds of ca.390 m a-1 associated with steep ice falls. The lower reaches of thedebris-covered tongues of Verde and Casa Pangue glaciers are almost stagnant,whereas Ventisquero Negro, another debris-covered glacier, shows accelerationat the front due to calving into a proglacial lake. Low elevationdebris-covered glacier tongues show increasing velocities at the beginning ofthe accumulation season whereas higher elevation, clean-ice tongues reducetheir speed during this period. This contrasting behavior is probably inresponse to an increase in water input to the subglacial system from winterrainfall events at low elevations and a decrease in melt water production athigher elevations. These sequential velocity maps can help to identify thecontrols on glacier surface velocity, aid in the delimitation of ice dividesand could also contribute to more realistic calibration of ice flux-massbalance models in this glacierized area.