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

In this study, we analyze the dynamic process of ice-dam formation by the Glaciar Perito Moreno (GPM), located on the Argentinean side of the southern tip of South America. When this glacier advances through the waters Lago Argentino and reaches the Península de Magallanes (PM), it has been regularly producing an ice-dam between the Brazo Rico (BR) and Canal de los Témpanos (CT-LA) since the early twentieth century; the last registered episode was in February 2016. Using the Advance-Close-Open-Retreat (ACOR) concept, we analyze the oscillation cycle of GPM, the feedback mechanism. From limnimetric scales observations during the 1994–2015 time period, it can be demonstrated that GPM exhibits different behaviors during the charge and discharge processes, classified by three types of outburst: sudden, progressive, and minor. The maximum discharge rate of a sudden event goes up to 8000 m 3 s − 1 , while a minor event may be as low as 123 m 3 s − 1 . To obtain detailed shape information of ice-dam formation at high temporal resolution, daily time-lapse images were acquired by two professional DSLR cameras from April 2012 to April 2013. The daily data allows for accurate estimation of the position and its rate of change in the terminus area of the glacier where the ice-dam develops, including the estimation of the height and width of the drainage tunnel forming at the base of the ice-dam. The glacier is advancing between June and December, and retreating between December and April. Based on the time-lapse image measurements, the forward and retreat motion of the glacier was estimated to be 0.53 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 to be ± 65 m in this period. The results obtained by the methods and techniques implemented have clearly demonstrate that the annual advance of the glacier front typically leads to an ice-dam formation, which is a complex process, and there is a feedback mechanism between GPM and LA that primarily controls the oscillations of the glacier front around the otherwise quite stable position. [ABSTRACT FROM AUTHOR]