Recent surge of the South Rimo Glacier, Karakoram: Dynamics Characterization using SAR data

2021 ◽  
Author(s):  
Shiyi Li ◽  
Philipp Bernhard ◽  
Irena Hajnsek ◽  
Silvan Leinss
Keyword(s):  
Surface Velocity ◽  
Maximum Height ◽  
The South ◽  
Velocity Change ◽  
Quiescent Phase ◽  
Glacier Terminus ◽  
Outburst Floods ◽  
Digital Elevation ◽  
Local Residents ◽  
Offset Tracking

<p>Glacier surging is an unique dynamic pattern that involves a long term quiescent phase and a sudden surge phase. The surge causes abnormal glacier movement, such as high flow velocity, transportation of large amount of ice mass, and dramatic thickening and advancing of the glacier terminus. Glacier surge not only confound the understanding of regional glacier dynamics, but also pose threats to local residents by invoking glacier lake outburst floods. </p><p>In this work, we reported the recent surge event of the South Rimo Glacier, one of the largest glaciers in Karakorum. The surge happened between 2018-2020 with very little terminus advancement, and thus it is difficult to interpret the dynamics of the event simply by visual inspections of satellite images. We studied both the topography evolution and the surface velocity change of the glacier before and during the surge. By differencing a series of digital elevation models (DEMs) produced from the TanDEM-x CoSSC data acquired between 2011 and 2017, we found that the South Rimo glacier started accumulating height in the middle stream since 2013. A bulge was built in the reservoir region since 2014 and reached its maximum height (27.51m higher than 2011) before the surge activation in 2017. Velocity maps between 2016-2020 were obtained from SAR offset tracking using Sentinel-1 images. It was shown that the surface velocity greatly increased in 2017 at areas around the bulge. The peak velocity was found in the mid of 2019 at about 10 m/day, which is of three magnitude higher than the velocity during the quiescent phase. Our work characterized the development of the recent surge of the South Rimo Glacier, and highlighted the value of high resolution DEM products and velocity maps in pre-identifying glacier surge and mitigating related hazards.</p>

scholarly journals Dynamics of Dalk Glacier in East Antarctica Derived from Multisource Satellite Observations Since 2000

2020 ◽  
Vol 12 (11) ◽  
pp. 1809
Author(s):  
Yiming Chen ◽  
Chunxia Zhou ◽  
Songtao Ai ◽  
Qi Liang ◽  
Lei Zheng ◽  
...  
Keyword(s):  
East Antarctica ◽  
Surface Velocity ◽  
Cyclic Behavior ◽  
Glacier Terminus ◽  
Digital Elevation ◽  
Ice Velocity ◽  
Velocity Changes ◽  
Elevation Model ◽  
Surface Ice

Monitoring variability in outlet glaciers can improve the understanding of feedbacks associated with calving, ocean thermal forcing, and climate change. In this study, we present a remote-sensing investigation of Dalk Glacier in East Antarctica to analyze its dynamic changes. Terminus positions and surface ice velocities were estimated from Landsat and Sentinel-1 data, and the high-precision Worldview digital elevation model (DEM) was generated to determine the location of the potential ice rumple. We detected the cyclic behavior of glacier terminus changes and similar periodic increases in surface velocity since 2000. The terminus retreated in 2006, 2009, 2010, and 2016 and advanced in other years. The surface velocity of Dalk Glacier has a 5-year cycle with interannual speed-ups in 2007, 2012, and 2017. Our observations show the relationship between velocity changes and terminus variations, as well as the driving role of the ice rumple. Ice velocity often increases after calving events and continuous retreats. The loss of buttressing provided by an ice rumple may be a primary factor for increases in ice velocity. Given the restriction of the ice rumple, the surface velocity remains relatively stable when the glacier advances. The calving events may be linked to the unstable terminus caused by the ice rumple.

scholarly journals RECENT DYNAMICAL FEATURES OF TYNDALL AND GREY GLACIERS, FROM SOUTHERN PATAGONIAN ICEFIELD, BY USING SATELLITE REMOTE SENSING TECHNIQUES

2020 ◽  
Vol XLII-3/W12-2020 ◽  
pp. 453-458
Author(s):  
A. C. M. Luzardi ◽  
C. Cárdenas
Keyword(s):  
Remote Sensing ◽  
Surface Velocity ◽  
Delayed Response ◽  
Ice Flow ◽  
Temperature Changes ◽  
Glacier Terminus ◽  
Dynamical Features ◽  
Remote Sensing Techniques ◽  
Offset Tracking ◽  
Sentinel 2

Abstract. Most glaciers in Patagonia have been rapidly shrinking during the past decades in response to ongoing global warming. To extend techniques to monitor their dynamics is crucial to understand individual glacier response to climate change and its consequences. In that context, our study aims to investigate recent dynamic behaviour of two near-site outlet glaciers placed at the Southern Patagonian Icefield (Tyndall and Grey glaciers) with the usage of simple and cheap remote sensing techniques. Sentinel-1 images were used to estimate surface velocity by using the Offset-tracking algorithm, while Sentinel-2 images were used to estimate area change in the ice front. Moreover, climatic variables (e.g., accumulated precipitation and air temperature) were analysed in order to assess its influence on glacier dynamics. Our results indicates that precipitation rather then temperature changes has been playing a major role in both glaciers retreat. While Tyndall tends to stabilize its retreat, Grey exponentially enhances retreat by its east tongue. Additionally, mean ice speed was of 0.448 ± 0.242 m.day−1 for Grey and 0.439 ± 0.245 m.day−1 for Tyndall, which agrees with literature. However, high ice speeds near the ice front indicated by previous work could not be captured here. Our results also suggests that ice flow is a delayed response of precipitation in the accumulation zone, and that may be the cause of decrease in Tyndall’s retreat. Overall, Offset-tracking is an useful tool for studying time series of Patagonian glaciers dynamics. It should be used carefully, however, around high dynamical regions such as the glacier terminus.

scholarly journals The propagation of a surge front on Bering Glacier, Alaska, 2001–2011

2013 ◽  
Vol 54 (63) ◽  
pp. 221-228 ◽  
Author(s):  
James Turrin ◽  
Richard R. Forster ◽  
Chris Larsen ◽  
Jeanne Sauber
Keyword(s):  
Feature Tracking ◽  
Average Rate ◽  
Surface Velocity ◽  
Ablation Zone ◽  
Ice Surface ◽  
Glacier Terminus ◽  
Bering Glacier ◽  
Landsat 7 ◽  
Ice Velocity ◽  
Recent Activity

AbstractBering Glacier, Alaska, USA, has a ∼20 year surge cycle, with its most recent surge reaching the terminus in 2011. To study this most recent activity a time series of ice velocity maps was produced by applying optical feature-tracking methods to Landsat-7 ETM+ imagery spanning 2001-11. The velocity maps show a yearly increase in ice surface velocity associated with the down-glacier movement of a surge front. In 2008/09 the maximum ice surface velocity was 1.5 ±0.017 km a-1 in the mid-ablation zone, which decreased to 1.2 ±0.015 km a-1 in 2009/10 in the lower ablation zone, and then increased to nearly 4.4 ± 0.03 km a-1 in summer 2011 when the surge front reached the glacier terminus. The surge front propagated down-glacier as a kinematic wave at an average rate of 4.4 ±2.0 km a-1 between September 2002 and April 2009, then accelerated to 13.9 ± 2.0 km a-1 as it entered the piedmont lobe between April 2009 and September 2010. The wave seems to have initiated near the confluence of Bering Glacier and Bagley Ice Valley as early as 2001, and the surge was triggered in 2008 further down-glacier in the mid-ablation zone after the wave passed an ice reservoir area.

scholarly journals Status of Major Glaciers of Hunza River Basin, Under Changing Climatic Conditions of Pakistan Over the Period of (1990-2018)

2021 ◽  
Author(s):  
Sajid Ali ◽  
Garee Khan ◽  
Wajid Hassan ◽  
Javed Akhter Qureshi ◽  
Iram Bano
Keyword(s):  
River Basin ◽  
Primary Source ◽  
Climatic Conditions ◽  
Climate Data ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Digital Elevation ◽  
Remote Sensing Techniques ◽  
Elevation Model ◽  
Hunza River

Abstract Ice masses and snow of Hunza River Basin (HRB) are an important primary source of fresh water and lifeline for downstream inhabitants. Changing climatic conditions seriously put an impact on these available ice and snow masses. These glaciers may affect downstream population by glacial lake outburst floods (GLOF) and surge events due to climatic variation. So, monitoring of these glaciers and available ice masses are important. This research delivers an approach for selected glaciers of the Hunza river basin. An attempt is made in this study using Landsat (OLI, ETM, ETM+, TM), digital elevation model (DEM), Geographic Information System and Remote Sensing techniques (RS&GIS) techniques. We delineated 27 glaciers within HRB from the period of 1990-2018. These glaciers' total area is about 2589.75 ±86km 2 in 1990 and about 2565.12 ±68km 2 in 2018. Our results revealed that from 2009 to 2015, glacier coverage of HRB advanced with a mean annual advance rate of 2.22±0.1 km 2 a -1 . Conversely, from 1994 to 1999, the strongest reduction in glacier area with a mean rate of - 3.126±0.3km 2 a -1 is recorded. The glaciers of HRB are relatively stable compared to Hindukush, Himalayan and Tibetan Plateau (TP) region of the world. The steep slope glacier's retreat rate is more than that of gentle slope glaciers, and the glaciers below elevation of 5000 m above sea level change significantly. Based on climate data from 1995-2018, HRB shows a decreasing trend in temperature and increasing precipitation. The glacier area's overall retreat is due to an increase in summer temperature while the glacier advancement is induced possibly by winter and autumn precipitation.

Il turismo responsabile e il rapporto coi residenti

2014 ◽  
pp. 83-102
Author(s):  
Sergio Fadini
Keyword(s):  
Sustainable Development ◽  
Economic Activity ◽  
Local Communities ◽  
The South ◽  
Tourism Impact ◽  
Local Residents ◽  
Tourism Destinations ◽  
A Site ◽  
The Relationship ◽  
Responsible Tourism

The relationship between tourism and local residents is one of the most important problems of the tourist governance in a site; both in mature tourism destinations like European cultural towns, or in other sites, and where tourism is a novelty, so problems can be more. The concept of responsible tourism was born for helping local communities that bear tourism impact, using the values of sustainable development. So, inside it, this theme is very important, for who think that local communites must be more active in tourism; and for who think that it’s enough if they gain money from tourist activities. This paper analyzes the situation in Matera, a little town in the south of Italy, where tourism is becoming an important economic activity. Here there are daily problems between who plan and citizens. A planning concerning not only tourism, as the restricted traffic zone.

scholarly journals Measuring Decadal Vertical Land-level Changes from SRTM-C (2000) and TanDEM-X (~ 2015) in the South-Central Andes

2018 ◽  
Author(s):  
Benjamin Purinton ◽  
Bodo Bookhagen
Keyword(s):  
Central Andes ◽  
Control Surface ◽  
The South ◽  
High Resolution Data ◽  
Gravel Bed ◽  
South Central ◽  
Digital Elevation ◽  
Mountain Belts ◽  
Elevation Model ◽  
Limit Detection

Abstract. Vertical change is often measured in the cryosphere via digital elevation model (DEM) differencing to assess glacier and ice-sheet mass balances. This requires the signal of change to outweigh the noise associated with the datasets. On the ice-free earth, land-level change is much smaller in magnitude and thus requires more accurate DEMs for differencing and identification of change. Previously, this has required high-resolution data at small scales. For the first time we measure land-level changes at the scale of entire mountain belts in the south-central Andes using the SRTM-C (collected in 2000) and the TanDEM-X (collected from 2010–2015), both spaceborne radar DEMs. Long-standing errors in the SRTM-C are corrected using the TanDEM-X as a control surface and applying cosine-fit co-registration to remove ~ 1/10 pixel (~ 3 m) shifts, Fast Fourier Transform and filtering to remove SRTM-C short- and long-wavelength stripes, and blocked shifting to remove remaining complex biases. The datasets are then differenced and outlier pixels are identified as potential signal for the case of gravel-bed channels and hillslopes. We are able to identify signals of incision and aggradation (with magnitudes down to ~ 3 m in best case) in two > 100 km river reaches, with increased geomorphic activity downstream of knickpoints. Anthropogenic gravel excavation and piling is prominently measured, with magnitudes exceeding ±5 m (up to > 10 m for large piles). These values correspond to conservative rates of 0.2 to > 0.5 m/yr for vertical changes in gravel-bed rivers. For hillslopes, since we require stricter cutoffs for noise, we are only able to identify one major landslide with a deposit volume of 16 ± 0.15 × 106 m3. Additional signals of change can be garnered from TanDEM-X auxiliary layers, however, these are more difficult to quantify. The methods presented can be extended to any region of the world with SRTM-C and TanDEM-X coverage where vertical land-level changes are of interest, with the caveat that remaining vertical uncertainties in primarily the SRTM-C limit detection in steep and complex topography.

scholarly journals Mapping tide-water glacier dynamics in East Greenland using Landsat data

1995 ◽  
Vol 41 (139) ◽  
pp. 584-595 ◽  
Author(s):  
John L. Dwyer
Keyword(s):  
Cross Correlation ◽  
Drainage Basin ◽  
Surface Velocity ◽  
Key Factors ◽  
Remotely Sensed Data ◽  
East Greenland ◽  
Ice Surface ◽  
Glacier Terminus ◽  
Glacier Dynamics ◽  
Continuous Presence

AbstractLandsat multispectral scanner and thematic mapper images were co-registered For the Kangerdlugssuaq Fjord region in East Greenland and were used to map glacier drainage-basin areas, changes in the positions of tide-water glacier termini and to estimate surface velocities of the larger tide-water glaciers. Statistics were compiled to document distance and area changes to glacier termini. The methodologies developed in this study are broadly applicable to the investigation of tide-water glaciers in other areas. The number of images available for consecutive years and the accuracy with which images are co-registered are key factors that influence the degree to which regional glacier dynamics can be characterized using remotely sensed data.Three domains of glacier state were interpreted: net increase in terminus area in the southern part of the study area, net loss of terminus area for glaciers in upper Kangerdlugssuaq Fjord and a slight loss of glacier terminus area northward from Ryberg Fjord. Local increases in the concentrations of drifting icebergs in the fjords coincide with the observed extension of glacier termini positions Ice-surface velocity estimates were derived for several glaciers using automated image cross-correlation techniques The velocity determined for Kangerdlugssuaq Gletscher is approximately 5.0 km a−1and that for Kong Christian IV Gletscher is 0.9 km a−1. The continuous presence of icebergs and brash ice in front of these glaciers indicates sustained rates of ice-front calving.

scholarly journals Airborne and spaceborne DEM- and laser altimetry-derived surface elevation and volume changes of the Bering Glacier system, Alaska, USA, and Yukon, Canada, 1972–2006

2009 ◽  
Vol 55 (190) ◽  
pp. 316-326 ◽  
Author(s):  
Reginald R. Muskett ◽  
Craig S. Lingle ◽  
Jeanne M. Sauber ◽  
Austin S. Post ◽  
Wendell V. Tangborn ◽  
...  
Keyword(s):  
Surface Elevation ◽  
Laser Altimetry ◽  
Volume Changes ◽  
The North ◽  
Glacier System ◽  
Outburst Floods ◽  
Digital Elevation ◽  
Bering Glacier ◽  
Elevation Changes ◽  
Terra Modis

AbstractUsing airborne and spaceborne high-resolution digital elevation models and laser altimetry, we present estimates of interannual and multi-decadal surface elevation changes on the Bering Glacier system, Alaska, USA, and Yukon, Canada, from 1972 to 2006. We find: (1) the rate of lowering during 1972–95 was 0.9 ± 0.1 m a−1; (2) this rate accelerated to 3.0 ± 0.7 m a−1 during 1995–2000; and (3) during 2000–03 the lowering rate was 1.5 ± 0.4 m a−1. From 1972 to 2003, 70% of the area of the system experienced a volume loss of 191 ± 17 km3, which was an area-average surface elevation lowering of 1.7 ± 0.2 m a−1. From November 2004 to November 2006, surface elevations across Bering Glacier, from McIntosh Peak on the south to Waxell Ridge on the north, rose as much as 53 m. Up-glacier on Bagley Ice Valley about 10 km east of Juniper Island nunatak, surface elevations lowered as much as 28 m from October 2003 to October 2006. NASA Terra/MODIS observations from May to September 2006 indicated muddy outburst floods from the Bering terminus into Vitus Lake. This suggests basal–englacial hydrologic storage changes were a contributing factor in the surface elevation changes in the fall of 2006.

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