New evidence of glacier surges in the Central Andes of Argentina and Chile

Abstract

In contrast to the large surge-type glacier clusters widely known for several mountain ranges around the world, the presence of surging glaciers in the Andes has been historically seen as marginal. The improved availability of satellite imagery during the last years facilitates investigating of glaciers in more detail even in remote areas. The purpose of the study was therefore to revisit existing information about surge-type glaciers for the Central Andes of Argentina and Chile (32° 40′–34° 20′ S), to identify and characterize possible further surge-type glaciers, providing new insights into the mass balance and evolution of the velocity of selected glaciers during the surge phase. Based on the analysis of 1962–2015 satellite imagery, historical aerial images, differencing of digital elevation models and a literature survey, we identified 21 surge-type glaciers in the study area. Eleven surge events and six possible surge-type glaciers were identified and described for the first time. The estimation of annual elevation changes of these glaciers for the 2000–2011 period, which encompasses the latest surge events in the region, showed heterogeneous behavior with strongly negative to positive surface elevation change patterns (−1.1 to +1.0 m yr−1). Additionally, we calculated maximum surface velocities of 3±1.9 m d−1 and 3.1±1.1 m d−1 for two of the glaciers during the latest identifiable surge events of 1985–1987 and 2003–2007. Within this glacier cluster, highly variable advance rates (0.01–1 km yr−1) and dissimilar surface velocities at the surge peak (3–35 m d−1) were observed. In comparison with other clusters worldwide, surge-type glaciers in the Central Andes are on average smaller and show minor absolute advances. Generally low velocities and the heterogeneous duration of the surge cycles are common between them and glaciers in the Karakorum, a region with similar climatic characteristics and many known surge-type glaciers. As a definitive assertion concerning the underlying surge mechanism of surges in the Central Andes could not be drawn based on the remote sensing data, this opens more detailed research avenues for surge-type glaciers in the region.

Glacier Variations at Xinqingfeng and Malan Ice Caps in the Inner Tibetan Plateau Since 1970

“…Two surge models have been linked to a corresponding hypothesis relative to thermal or hydrological surge control [71,72]. Thermal control is characterized by an initiation phase that lasts several years before reaching a peak in the surge and a termination phase that consists of several years of deceleration following the surge peak [73,74].…”

Six Decades (1958–2018) of Geodetic Glacier Mass Balance in Monte San Lorenzo, Patagonian Andes

“…The estimation of elevation change for a given glacier has an associated uncertainty, which depends on the quality of the two DEMs utilized on each time interval. To calculate this random uncertainty, we apply the same procedure and equations described in detail in Falaschi et al (2018), which in essence comes back to the approach of Gardelle et al (2013). Also, Koblet et al (2010) provide the means for calculating the systematic uncertainty which, because it can have positive or negative sign, is subtracted or added to the elevation change signal.…”

Brief communication: Collapse of 4 Mm<sup>3</sup> of ice from a cirque glacier in the Central Andes of Argentina

“…The Aru twin collapses in Tibet were preceded by geometry changes in the form of surge-like behaviour (Kääb et al, 2018). Although surges in this region of the Andes and in close proximity to the Leñas Glacier have been documented (Falaschi et al, 2018b), we were unable to detect any evidence of a surge leading to collapse in the satellite imagery and DEMs. As for a change in thermal regime, from the rock glaciers in the area and the long preservation of the collapse deposits we conclude a potentially cold ground temperature regime for parts of the glacier and forefield.…”

“…We used the CHIRPS daily precipitation data (Funk et al, 2015), with a spatial resolution of 0.05 • , to identify unusu- ally high rainfall occurrences. During the period 4-15 March 2007, no precipitation was recorded in the CHIRPS pixel where the Leñas collapse occurred and its surrounding pixels.…”