Analyzing the oscillations of the Perito Moreno Glacier, using time-lapse image sequences

LENZANO, MARÍA G.; LANNUTTI, ESTEBAN; TOTH, CHARLES; LENZANO, LUIS; LO VECCHIO, ANDRÉS; FALASCHI, DANIEL; VICH, ALBERTO

COLD REGIONS SCIENCE AND TECHNOLOGY

ELSEVIER SCIENCE BV

Año: 2018 vol. 146 p. 155 - 166

0165-232X

In this study, we analyze the dynamic process of ice-dam formation by the Glaciar Perito Moreno (GPM), locatedon the Argentinean side of the southern tip of South America. When this glacier advances through the watersLago Argentino and reaches the Península de Magallanes (PM), it has been regularly producing an ice-dambetween the Brazo Rico (BR) and Canal de los Témpanos (CT-LA) since the early twentieth century; the lastregistered episode was in February 2016. Using the Advance-Close-Open-Retreat (ACOR) concept, we analyzethe oscillation cycle of GPM, the feedback mechanism. From limnimetric scales observations during the1994?2015 time period, it can be demonstrated that GPM exhibits different behaviors during the charge anddischarge processes, classified by three types of outburst: sudden, progressive, and minor. The maximum dischargerate of a sudden event goes up to 8000 m3 s−1, while a minor event may be as low as 123 m3 s−1. Toobtain detailed shape information of ice-dam formation at high temporal resolution, daily time-lapse imageswere acquired by two professional DSLR cameras from April 2012 to April 2013. The daily data allows foraccurate estimation of the position and its rate of change in the terminus area of the glacier where the ice-damdevelops, including the estimation of the height and width of the drainage tunnel forming at the base of the icedam.The glacier is advancing between June and December, and retreating between December and April. Basedon the time-lapse image measurements, the forward and retreat motion of the glacier was estimated to be0.53 m day−1 and −1.1 m day−1 with an estimation error of± 0.04 m day−1 between April to October (2012)and January and April (2013), respectively. The seasonal variation in the position of the glacier was found tobe± 65 m in this period. The results obtained by the methods and techniques implemented have clearly demonstratethat the annual advance of the glacier front typically leads to an ice-dam formation, which is acomplex process, and there is a feedback mechanism between GPM and LA that primarily controls the oscillationsof the glacier front around the otherwise quite stable position.