Surface velocity fields of active rock glaciers and ice‐debris complexes in the Central Andes of Argentina

Abstract

Rock glaciers and transitional ice‐debris complexes predominate the Central Andean landform assemblage, yet regional studies on their state of activity and their kinematics remain sparse. Here we utilize the national glacier inventory of Argentina to quantify surface velocity fields of 244 rock glaciers and 51 ice‐debris complexes, located in the Cordón del Plata range, Argentina. Applying a feature‐tracking approach to repeated RapidEye satellite imagery acquired between 2010 and 2017/18, we find mean displacement rates between 0.37 and 2.61 m year−1 for 149 landforms, while for the remaining 146 features, surface movement remains below our level of detection. We compare our satellite‐derived velocity fields with ground‐truth data from two local field sites and find closely matching results in magnitude and spatial distribution. With average displacement of one‐third of the active rock glaciers and ice‐debris complexes exceeding 1 m year−1, the region hosts an exceptional number of fast‐flowing periglacial landforms, compared to other mountain belts. Using a random forest model, we test the predictive power of 25 morphometric and topoclimatic candidate predictors for modelling the state of activity of rock glaciers and ice‐debris complexes on two different scales. For entire landforms and individual landform segments, constructed along displacement centrelines, we can predict the state of activity with overall accuracies of 70.08% (mean AUROC = 0.785) and 74.86% (mean AUROC = 0.753), respectively. While topoclimatic parameters such as solar radiation and elevation are most important for entire landforms, geometric parameters become more important at the scale of landform segments. Despite tentative correlations between local slope and surface kinematics, our results point to factors integrating slope and distance to the source to govern local deformation. We conclude that feature tracking in optical imagery is feasible for regional studies in remote regions and provides valuable insight into the current state of the Andean cryosphere. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd

Combination of Aerial, Satellite, and UAV Photogrammetry for Quantifying Rock Glacier Kinematics in the Dry Andes of Chile (30°S) Since the 1950s

“…In our study area, despite their relatively small size, the kinematic results on the three most active landforms show velocity rates that are comparable to the rock glaciers in the northern Tien Shan region (Kääb et al, 2021) and the Cordón del Plata range (Blöthe et al, 2020). The general acceleration trend since the 2000s that we observed with our results is in reasonable agreement with values reported elsewhere in the Northern Hemisphere (Hartl et al, 2016;Necsoiu et al, 2016;Eriksen et al, 2018;PERMOS et al, 2019;Kääb et al, 2021).…”

“…Terrestrial geodetic surveys have been sporadically implemented at the Tapado rock glaciers since 2009 (Dirección General de Aguas [DGA], 2010), between 2012 and 2016 at the Varas rock glacier (23 °S) in the Norwest Argentinean Andes (Martini et al, 2017) and between 2013 and 2016 at the Morenas Coloradas rock glacier (32 °S) in the Central Argentinean Andes (Trombotto-Liaudat and Bottegal, 2020). More recently, Blöthe et al (2020) provided the surface velocities of 244 rock glaciers between 2010 and 2018 in the Cordón del Plata Range (Central Argentinean Andes) using highresolution satellite images and cross-correlation matching techniques. Using a combination of UAV and geophysical surveys, Halla et al (2021) investigated the surface kinematics, ice content and interannual water storage at the Dos Lenguas rock glacier, approximately 15 km to the southeast of the Tapado area.…”

Novel Machine Learning Method Integrating Ensemble Learning and Deep Learning for Mapping Debris-Covered Glaciers

“…The velocity of glacier movement is a key factor for understanding the nature of glaciers and quantifying glacier changes, and it is also an important metric for glacier dynamics [4]. A frequency domain algorithm was used in Landsat 8 OLI images (panchromatic band, 15 m resolution) taken approximately one year apart between the two periods to calculate the correlation coefficient in the COSI-Corr software, with the reference window set to 128 and the search window set to 32, to obtain the glacier movement velocity data (Figure 2).…”

“…Glacier changes have significant effects on the local climate, ecological environment, water resources, and sea-level rise [1][2][3]. From the perspective of global warming, the average temperature of High Mountain Asia (HMA) [4,5]-a region that has the largest number of glaciers (95,500) and ice reserves (7.02 ± 1.82 × 10 3 km 3 ) outside of the polar regions [6]-has also risen [7,8]. This has put the Qinghai-Tibet Plateau in a state of negative energy balance on the surface, causing most glaciers to retreat [9,10].…”

Rock Glacier Characteristics Under Semiarid Climate Conditions in the Western Nyainqêntanglha Range, Tibetan Plateau

“…In semiarid and highly elevated mountain ranges, like the northern part of the western Nyainqêntanglha range (Anslan et al., 2020; Bolch et al., 2010), the extent of the source areas for moisture and sediment of the rock glacier might be limited (Blöthe et al., 2020; Humlum, 2000; Janke & Frauenfelder, 2008). In general, the moisture of rock glacier ice can originate from precipitation, snow or glacial melt, as well as debris‐covered glacial remnants.…”