scholarly journals Glacier and Rock Glacier changes since the 1950s in the La Laguna catchment, Chile

2021 ◽  
Author(s):  
Benjamin Aubrey Robson ◽  
Shelley MacDonell ◽  
Álvaro Ayala ◽  
Tobias Bolch ◽  
Pål Ringkjøb Nielsen ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Balance ◽  
Shuttle Radar Topography Mission ◽  
Airborne Lidar ◽  
Rock Glacier ◽  
Glacier Changes ◽  
Elevation Changes ◽  
Rock Glaciers ◽  
The 1950S ◽  
Glacial Landforms

Abstract. Glaciers and rock glaciers play an important role in the hydrology of the semi-arid Northern Chile. Several studies show that glaciers have strongly lost mass in response to climate change during the last decades. The response to rock glaciers in this region is, however, much less investigated. In this study we use a combination of historical aerial photography, stereo satellite imagery, airborne LiDAR, and the Shuttle Radar Topography Mission (SRTM) DEM to report glacier changes for the Tapado Glacier-Rock Glacier complex from the 1950s to 2020 and to report mass balances for the glacier component of the complex, Tapado Glacier. Furthermore, we examine high-resolution elevation changes and surface velocities between 2012 and 2020 for 40 rock glaciers in La Laguna catchment. Our results show how the glacier has lost 25.2 ± 4.6 % of its ice covered area between 1956 and 2020, while the mass balance of Tapado Glacier has become steadily more negative, from being approximately in balance between 1956 and 1978 (−0.04 ± 0.08 m w.e. a−1) to showing strong losses between 2015 and 2020 (−0.32 ± 0.08 m w.e. a−1). Climatological (re)-analyses reveal a general increase in air temperature, decrease in humidity, and variable precipitation since the 1980s in the region. In particular the severe droughts in the region starting in 2010 resulted in a particular negative mass balance of −0.54 ± 0.10 m w.e. a−1 between 2012 and 2015. The rock glaciers within La Laguna catchment show heterogenous changes with some sections of landforms exhibiting pronounced elevation changes and surface velocities exceeding that of Tapado Glacier. This could be indicative of high ice contents within the landforms and also highlights the importance of considering how landforms can transition from more glacial landforms to more periglacial features under permafrost conditions. As such, we believe high-resolution (sub-metre) elevation changes and surface velocities are a useful first step for identifying ice-rich landforms.

scholarly journals Inventory, motion and acceleration of rock glaciers in Ile Alatau and Kungöy Ala-Too, northern Tien Shan, since the 1950s

2020 ◽  
Author(s):  
Andreas Kääb ◽  
Tazio Strozzi ◽  
Tobias Bolch ◽  
Rafael Caduff ◽  
Håkon Trefall ◽  
...  
Keyword(s):  
Sediment Transport ◽  
High Resolution ◽  
Tien Shan ◽  
Spatial And Temporal Variability ◽  
European Alps ◽  
Rock Glacier ◽  
Study Region ◽  
Rock Glaciers ◽  
The 1950S ◽  
Northern Tien Shan

Abstract. Spatio-temporal patterns of rock glacier creep have rarely been studied outside the densely populated European Alps. This study investigates the spatial and temporal variability of rock glacier motion in the Ile Alatau and Kungöy Ala-Too mountain ranges, northern Tien Shan. Over the study region of more than 3000 km2, an inventory of slope movements is constructed using a large number of radar interferograms and high-resolution optical imagery. The inventory includes more than 900 landforms, of which around 550 are interpreted as rock glaciers. Out of the active rock glaciers, 45 are characterised by a rate of motion exceeding 1 m/a. From these fast rock glaciers we select six and study them in more detail (Gorodetzky, Morenny, Archaly, Ordzhonikidze, Karakoram and Kugalan Tash rock glaciers) using offset tracking between airphotos, and historical and modern very high resolution optical satellite data. Most of them show an overall increase of decadal surface velocities from the 1950s onwards with speeds being roughly two to three times higher in recent years compared to the 1950s and 1960s. This development indicates a possible significant increase in sediment and ice fluxes through rock glaciers and implies that – when compared to glacier shrinkage – periglacial sediment transport in the region seems to gain importance relative to glacial sediment transport. Those rock glacier fronts reaching the valley floors show a strongly compressive flow regime, and changes in speeds further upstream affect them only in a damped way. The only rock glacier investigated in detail that does not exhibit an overall increase in speed since the 1950s is Gorodetsky where glacier retreat and dead-ice degradation seem to have decoupled the rock glacier from its supply by glacial sediments and ice.

scholarly journals Inventory and changes of rock glacier creep speeds in Ile Alatau and Kungöy Ala-Too, northern Tien Shan, since the 1950s

2021 ◽  
Vol 15 (2) ◽  
pp. 927-949
Author(s):  
Andreas Kääb ◽  
Tazio Strozzi ◽  
Tobias Bolch ◽  
Rafael Caduff ◽  
Håkon Trefall ◽  
...  
Keyword(s):  
High Resolution ◽  
Tien Shan ◽  
Spatial And Temporal Variability ◽  
European Alps ◽  
Material Transport ◽  
Rock Glacier ◽  
Study Region ◽  
Rock Glaciers ◽  
The 1950S ◽  
Northern Tien Shan

Abstract. Spatio-temporal patterns related to the viscous creep in perennially frozen sediments of rock glaciers in cold mountains have rarely been studied outside the densely populated European Alps. This study investigates the spatial and temporal variability of rock glacier movement in the Ile Alatau and Kungöy Ala-Too mountain ranges, northern Tien Shan, a region with particularly large and fast rock glaciers. Over the study region of more than 3000 km2, an inventory of slope movements was constructed using a large number of radar interferograms and high-resolution optical imagery. The inventory includes more than 900 landforms, of which around 550 were interpreted as rock glaciers. Out of the active rock glaciers inventoried, 45 are characterized by a rate of motion exceeding 100 cm/a. From these fast rock glaciers we selected six (Gorodetzky, Morenny, Archaly, Ordzhonikidze, Karakoram, and Kugalan Tash) and studied them in more detail using offset tracking between repeat aerial images and historical and modern high-resolution optical satellite data. Two of these rock glaciers showed a steady increase in decadal surface velocities from the 1950s onwards, with speeds being roughly 2 to 4 times higher in recent years compared to the 1950s and 1960s. Three rock glaciers showed similar accelerations over the last 1 to 2 decades but also phases of increased speeds in the 1960s. This development indicates a possible significant increase in current sediment and ice fluxes through rock glaciers and implies that their material transport in the region might gain geomorphodynamic importance relative to material transport by glaciers, assuming the latter decreases together with the regional glacier shrinkage. The study demonstrates how air and satellite image archives are exploited to construct one of the longest decennial times series of rock glacier speeds currently available. Our results are in line with findings from Europe about rock glacier speeds increasing with atmospheric warming and underline local variability of such an overall response.

scholarly journals Glacier elevation and mass changes over the central Karakoram region estimated from TanDEM-X and SRTM/X-SAR digital elevation models

2016 ◽  
Vol 57 (71) ◽  
pp. 273-281 ◽  
Author(s):  
Melanie Rankl ◽  
Matthias Braun
Keyword(s):  
High Resolution ◽  
Snow Cover ◽  
Digital Elevation Models ◽  
Mass Balances ◽  
Freshwater Resources ◽  
Digital Elevation ◽  
Glacier Changes ◽  
Kinematic Waves ◽  
Elevation Changes ◽  
River Communities

AbstractSnow cover and glaciers in the Karakoram region are important freshwater resources for many down-river communities as they provide water for irrigation and hydropower. A better understanding of current glacier changes is hence an important informational baseline. We present glacier elevation changes in the central Karakoram region using TanDEM-X and SRTM/X-SAR DEM differences between 2000 and 2012. We calculated elevation differences for glaciers with advancing and stable termini or surge-type glaciers separately using an inventory from a previous study. Glaciers with stable and advancing termini since the 1970s showed nearly balanced elevation changes of -0.09 ±0.12 m a-1 on average or mass budgets of -0.01 ±0.02Gt a-1 (using a density of 850 kg m-3). Our findings are in accordance with previous studies indicating stable or only slightly negative glacier mass balances during recent years in the Karakoram. The high-resolution elevation changes revealed distinct patterns of mass relocation at glacier surfaces during active surge cycles. The formation of kinematic waves at quiescent surge-type glaciers could be observed and points towards future active surge behaviour. Our study reveals the potential of the TanDEM-X mission to estimate geodetic glacier mass balances, but also points to still existing uncertainties induced by the geodetic method.

scholarly journals On the potential of very high-resolution repeat DEMs in glacial and periglacial environments

2010 ◽  
Vol 4 (1) ◽  
pp. 53-65 ◽  
Author(s):  
J. Abermann ◽  
A. Fischer ◽  
A. Lambrecht ◽  
T. Geist
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Airborne Lidar ◽  
Primary Data ◽  
Glacier Area ◽  
Airborne Laser ◽  
Multi Temporal ◽  
Rock Glaciers ◽  
Data Source ◽  
Very High

Abstract. The potential of high-resolution repeat DEMs was investigated for glaciological applications including periglacial features (e.g. rock glaciers). It was shown that glacier boundaries can be delineated using airborne LIDAR-DEMs as a primary data source and that information on debris cover extent could be extracted using multi-temporal DEMs. Problems and limitations are discussed, and accuracies quantified. Absolute deviations of airborne laser scanning (ALS) derived glacier boundaries from ground-truthed ones were below 4 m for 80% of the ground-truthed values. Overall, we estimated an accuracy of +/−1.5% of the glacier area for glaciers larger than 1 km2. The errors in the case of smaller glaciers did not exceed +/−5% of the glacier area. The use of repeat DEMs in order to obtain information on the extent, characteristics and activity of rock glaciers was investigated and discussed based on examples.

scholarly journals Estimating mass-wasting processes in active earth slides – earth flows with time-series of High-Resolution DEMs from photogrammetry and airborne LiDAR

2009 ◽  
Vol 9 (2) ◽  
pp. 433-439 ◽  
Author(s):  
A. Corsini ◽  
L. Borgatti ◽  
F. Cervi ◽  
A. Dahne ◽  
F. Ronchetti ◽  
...  
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Large Scale ◽  
Airborne Lidar ◽  
Mitigation Measures ◽  
Mass Wasting ◽  
Aerial Photos ◽  
Use Of Time ◽  
Elevation Changes ◽  
Earth Flows

Abstract. This paper deals with the use of time-series of High-Resolution Digital Elevation Models (HR DEMs) obtained from photogrammetry and airborne LiDAR coupled with aerial photos, to analyse the magnitude of recently reactivated large scale earth slides – earth flows located in the northern Apennines of Italy. The landslides underwent complete reactivation between 2001 and 2006, causing civil protection emergencies. With the final aim to support hazard assessment and the planning of mitigation measures, high-resolution DEMs are used to identify, quantify and visualize depletion and accumulation in the slope resulting from the reactivation of the mass movements. This information allows to quantify mass wasting, i.e. the amount of landslide material that is wasted during reactivation events due to stream erosion along the slope and at its bottom, resulting in sediment discharge into the local fluvial system, and to assess the total volumetric magnitude of the events. By quantifying and visualising elevation changes at the slope scale, results are also a valuable support for the comprehension of geomorphological processes acting behind the evolution of the analysed landslides.

scholarly journals Distribución espacial y temporal de glaciares, glaciares cubiertos y glaciares rocosos durante la última deglaciación en el valle de La Bonaigua (Pirineo Central)

2020 ◽  
Vol 46 (2) ◽  
pp. 413-446
Author(s):  
J. Ventura-Roca
Keyword(s):  
High Resolution ◽  
Little Ice Age ◽  
Ice Age ◽  
Lidar Data ◽  
Forest Environment ◽  
Digital Elevation ◽  
Rock Glaciers ◽  
Elevation Model ◽  
Glacial Landforms ◽  
Central Pyrenees

The application of the paleogeographic method to the study of glacial landforms and rock glaciers allows their morphometric and sedimentological characterization, the establishment of a detailed morphostratigraphic sequence and a chronological proposal for the identified glacial phases. This study analyzes 86 landforms (57 glacial deposits, 21 rock glaciers and 8 protalus ramparts) in the Bonaigua Valley (Noguera Pallaresa Basin, Central Pyrenees), with special attention to the differentiation between debris-covered glaciers and rock glaciers. Other subjects studied concerning rock glaciers are: distinguish its glacial or periglacial origin; the possible current activity of some landforms, and the detection of rock glaciers located at low altitudes (in the current forest environment) through the use of high-resolution digital elevation model (2x2 m) from LIDAR data. The chronological hypothesis elaborated by correlation with other high Pyrenean valleys (with absolute ages available) includes 7 phases (6 glacial phases and 1 periglacial phase) in which co-exist and/or evolve, in a paraglacial dynamic, glaciers, debris-covered glaciers and rock glaciers, and that we temporarily place between the end of the Oldest Dryas and the Little Ice Age.

scholarly journals Glacier mass balance over the central Nyainqentanglha Range during recent decades derived from remote-sensing data

2019 ◽  
Vol 65 (251) ◽  
pp. 422-439 ◽  
Author(s):  
KUNPENG WU ◽  
SHIYIN LIU ◽  
ZONGLI JIANG ◽  
JUNLI XU ◽  
JUNFENG WEI
Keyword(s):  
Mass Balance ◽  
Remote Sensing Data ◽  
Shuttle Radar Topography Mission ◽  
Topographic Maps ◽  
Glacier Mass Balance ◽  
Glacier Area ◽  
Ice Surface ◽  
Digital Elevation ◽  
Elevation Changes ◽  
Elevation Model

ABSTRACTTo obtain information on changes in glacier mass balance in the central Nyainqentanglha Range, a comprehensive study was carried out based on digital-elevation models derived from the 1968 topographic maps, the Shuttle Radar Topography Mission DEM (2000) and TerraSAR-X/TanDEM-X (2013). Glacier area changes between 1968 and 2016 were derived from topographic maps and Landsat OLI images. This showed the area contained 715 glaciers, with an area of 1713.42 ± 51.82 km2, in 2016. Ice cover has been shrinking by 0.68 ± 0.05% a−1 since 1968. The glacier area covered by debris accounted for 11.9% of the total and decreased in the SE–NW directions. Using digital elevation model differencing and differential synthetic aperture radar interferometry, a significant mass loss of 0.46 ± 0.10 m w.e. a−1 has been recorded since 1968; mass losses accelerated from 0.42 ± 0.20 m w.e. a−1 to 0.60 ± 0.20 m w.e. a−1 between 1968–2000 and 2000–2013, with thinning noticeably greater on the debris-covered ice than the clean ice. Surface-elevation changes can be influenced by ice cliffs, as well as debris cover and land- or lake-terminating glaciers. Changes showed spatial and temporal heterogeneity and a substantial correlation with climate warming and decreased precipitation.

scholarly journals Remote-sensing estimate of glacier mass balance over the central Nyainqentanglha Range during 1968 – ∼ 2013

2018 ◽  
Author(s):  
Kunpeng Wu ◽  
Shiyin Liu ◽  
Zongli Jiang ◽  
Junli Xu ◽  
Junfeng Wei
Keyword(s):  
Mass Balance ◽  
Recent Decade ◽  
Shuttle Radar Topography Mission ◽  
Quality Data ◽  
Glacier Mass Balance ◽  
Glacier Area ◽  
Ice Surface ◽  
Air Temperatures ◽  
Digital Elevation ◽  
Elevation Changes

Abstract. With high air temperatures and annual precipitation, maritime glaciers in southeastern Tibet are sensitive to climate change. Current glaciological knowledge of those in the central Nyainqentanglha Range is still limited because of their inaccessibility and low-quality data. To obtain information on changes in glacier area, length and mass balance, a comprehensive study was carried out based on topographic maps and Landsat TM/ETM+/OLI images (1968 and 2016), and on digital-elevation models (DEM) derived from the 1968 maps, from the Shuttle Radar Topography Mission (SRTM) DEM (2000), and from TerraSAR-X/TanDEM-X (∼ 2013). This showed the area contained 715 glaciers, with an area of 1713.42 ± 51.82 km2, in 2016. Ice cover has been shrinking by 0.68 % ± 0.05% a−1 since 1968, although in the most recent decade this rate has slowed. The glacier area covered by debris accounted for 11.9 % of the total and decreased in SE-NW directions. Using DEM differencing and Differential Synthetic Aperture Radar Interferometry (DInSAR), a significant mass deficit of 0.46 ± 0.04 m w.e. a−1 has been recorded since 1968; mass losses accelerating from 0.42 ± 0.05 m w.e. a−1 to 0.60 ± 0.20 m w.e. a−1 during 1968–2000 and 2000–∼ 2013, with thinning noticeably greater on the debris-covered ice than the clean ice. Surface-elevation changes can be influenced by ice cliffs, as well as debris cover, and land- or lake-terminating glaciers and supraglacial lakes. Changes showed spatial and temporal heterogeneity and a substantial correlation with climate warming.

scholarly journals Rock Glacier Kinematics in the Kaunertal, Ötztal Alps, Austria

Geosciences ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 373 ◽  
Author(s):  
Till Groh ◽  
Jan Henrik Blöthe
Keyword(s):  
High Resolution ◽  
Aerial Imagery ◽  
Local Analysis ◽  
Data Sets ◽  
Rock Glacier ◽  
Glacier Inventory ◽  
Logistic Regression Models ◽  
Image Tracking ◽  
Rock Glaciers ◽  
Regional Basis

The quantification of rock glacier kinematics on a regional basis has gained increasing importance in recent years. Here, we applied an image tracking approach on high-resolution aerial imagery to infer surface kinematics of 129 mapped rock glaciers in the Kaunertal, Austrian Alps. We find significant surface movement for 30 features with mean velocities falling between 0.11 and 0.29 m yr−1 and a maximum of 1.7 m yr−1. Local analysis and comparison to earlier studies reveals significant increases in rock glacier velocities in the study area. From the rock glacier inventory and high-resolution digital topography, we computed a series of morphometric parameters to analyze potential controls on rock glacier creep and to predict rock glacier activity using random forests and logistic regression models. The results point towards a stronger dependence of velocities on parameters describing general inclination, potentially acting as proxies for internal rock glacier properties, while activity states seem to be regulated mainly by rock glacier dimensions and topoclimate. Using a parameter subset, we successfully separated active from inactive rock glaciers with accuracies of up to 77.5%, indicating a promising approach to predict rock glacier activity solely relying on parameters that can be derived from regionally available data sets.

scholarly journals Glacier changes in the Karakoram region mapped by multi-mission satellite imagery

2013 ◽  
Vol 7 (4) ◽  
pp. 4065-4099 ◽  
Author(s):  
M. Rankl ◽  
S. Vijay ◽  
C. Kienholz ◽  
M. Braun
Keyword(s):  
High Resolution ◽  
Landsat Imagery ◽  
Length Distribution ◽  
Shuttle Radar Topography Mission ◽  
Ice Dynamics ◽  
Mountain Glaciers ◽  
Digital Elevation ◽  
Spatial Coverage ◽  
Glacier Changes ◽  
Elevation Measurement

Abstract. Glaciers in the Karakoram region are known to show stable and advancing terminus positions or surging behavior, which contrasts the worldwide retreat of many mountain glaciers. The present study uses Landsat imagery to derive an updated and extended glacier inventory. Surging and advancing glaciers and their annual termini position changes are mapped in addition. Out of 1334 glaciers, 134 show advancing or surging behavior, with a marked increase since 2000. The length distribution of surging glaciers differs significantly from non-surging glaciers. More than 50% of the advancing/surging glaciers are shorter than 10 km. Besides a regional spatial coverage of ice dynamics, high-resolution SAR data allows to investigate very small and comparably fast flowing glaciers (up to 1.8 m day−1). Such data enables mapping of temporal changes of ice dynamics of individual small surging or advancing glaciers. In a further case study, glacier volume changes of three glaciers around Braldu Glacier are quantified during a surge event comparing digital elevation models from the Shuttle Radar Topography Mission (SRTM) and the new TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X) Mission. We recommend regular acquisitions of high resolution (bi-static) SAR satellite data and further exploitation of the archives in order to generate an improved database for monitoring changes, and to at least partially compensate for the lack of in-situ and long-term climatological measurements in the Karakoram region.

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