Multi-decadal ice-velocity and elevation changes of a monsoonal maritime glacier: Hailuogou glacier, China

2010 ◽  
Vol 56 (195) ◽  
pp. 65-74 ◽  
Author(s):  
Yong Zhang ◽  
Koji Fujita ◽  
Shiyin Liu ◽  
Qiao Liu ◽  
Xin Wang
Keyword(s):  
Thermal Emission ◽  
Surface Elevation ◽  
Aerial Photographs ◽  
Differential Gps ◽  
Glacier Surface ◽  
Ablation Area ◽  
Glacier Terminus ◽  
Digital Elevation ◽  
Elevation Changes ◽  
Ice Velocity

AbstractDigital elevation models (DEMs) of the ablation area of Hailuogou glacier, China, produced from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data obtained in 2009, differential GPS (DGPS) data surveyed in 2008 and aerial photographs acquired in 1966 and 1989 are differenced to estimate long- and short-term glacier surface elevation change (dh/dt). The mean dh/dt of the ablation area over 43 years (1966–2009) is −1.1 ± 0.4 m a−1. Since 1989 the thinning has accelerated significantly. Ice velocities measured by DGPS at 28 fixed stakes implanted in the ablation area increase with distance from the glacier terminus, ranging from 41.0 m a−1 approaching the glacier terminus to a maximum of 205.0 m a−1 at the base of an icefall. Our results reveal that the overall average ice velocity in the ablation area has undergone significant temporal variability over the past several decades. Changes in glacier surface elevation in the ablation area result from the combined effects of climate change and glacier dynamics, which are driven by different factors for different regions and periods.

scholarly journals Glacial changes of five southwest British Columbia icefields, Canada, mid-1980s to 1999

2008 ◽  
Vol 54 (186) ◽  
pp. 469-478 ◽  
Author(s):  
Jeffrey A. VanLooy ◽  
Richard R. Forster
Keyword(s):  
British Columbia ◽  
Satellite Images ◽  
Surface Elevation ◽  
Interferometric Synthetic Aperture Radar ◽  
Elevation Change ◽  
Glacier Terminus ◽  
M 10 ◽  
Digital Elevation ◽  
Surface Elevation Change ◽  
Elevation Changes

AbstractThis study adjusts and compares digital elevation models (DEMs) created from photogrammetric and interferometric synthetic aperture radar techniques to determine volume and surface elevation changes of five icefields in a remote region of southwest British Columbia, Canada, between the mid-1980s and 1999. Preliminary differences between the DEMs in ice-free and vegetation-free areas indicated variable elevation offsets with increasing altitude (11 m km−1) and with increasing slope (2.7 m (10°)−1). Results indicate a surface elevation change of −6.0 ± 2.7 m (−0.5 ± 0.2 m a−1) and a total volume loss of −19.4 ± 8.8 km3 (−1.5 ± 0.7 km3 a−1), which represents a potential sea-level rise contribution of 0.004 ± 0.002 mm a−1. Temperature and snowfall data from four nearby meteorological stations indicate that increased temperatures and decreased snowfall throughout the late 1980s and 1990s are a likely cause of the thinning. Glacier terminus positions were compared between a historical map (1927) and satellite images (1974, 1990/91 and 2000/01). All observed glaciers were in retreat between 1927 and 1974, as well as between 1990/91 and 2000/01, but many glaciers advanced or significantly slowed in their retreat between 1974 and 1990/91.

scholarly journals Seasonal Surface Change of Urumqi Glacier No. 1, Eastern Tien Shan, China, Revealed by Repeated High-Resolution UAV Photogrammetry

2021 ◽  
Vol 13 (17) ◽  
pp. 3398
Author(s):  
Puyu Wang ◽  
Hongliang Li ◽  
Zhongqin Li ◽  
Yushuo Liu ◽  
Chunhai Xu ◽  
...  
Keyword(s):  
Tien Shan ◽  
Surface Elevation ◽  
Surface Velocity ◽  
Elevation Change ◽  
The West ◽  
Glacier Surface ◽  
Surface Change ◽  
Ablation Area ◽  
Glacier Terminus ◽  
Surface Changes

The seasonal surface changes of glaciers in Tien Shan have seen little prior investigation despite the increase in geodetic studies of multi-year changes. In this study, we analyzed the potential of an Unmanned Aerial Vehicle (UAV) to analyze seasonal surface change processes of the Urumqi Glacier No. 1 in eastern Tien Shan. We carried out UAV surveys at the beginning and the end of the ablation period in 2018. The high-precision evolution of surface elevation, geodetic mass changes, surface velocity, and terminus change in the surveyed ablation area were correspondingly derived in combination with ground measurements, including stake/snow-pit observation and GPS measurement. The derived mean elevation change in the surveyed ablation area was −1.64 m, corresponding to the geodetic mass balance of approximately −1.39 m w.e. during the ablation period in 2018. The mean surface velocity was 3.3 m/yr and characterized by the spatial change of the velocity, which was less in the East Branch than in the West Branch. The UAV survey results were a little less than those from the ground measurements, and the correlation coefficient was 0.88 for the surface elevation change and 0.87 for surface displacement. The relative error of the glacier terminus change was 4.5% for the East Branch and 6.2% for the West Branch. These results show that UAV photogrammetry is ideal for assessing seasonal glacier surface changes and has a potential application in the monitoring of detailed glacier changes.

scholarly journals Quality Assessment and Glaciological Applications of Digital Elevation Models Derived from Space-Borne and Aerial Images over Two Tidewater Glaciers of Southern Spitsbergen

2019 ◽  
Vol 11 (9) ◽  
pp. 1121 ◽  
Author(s):  
Małgorzata Błaszczyk ◽  
Dariusz Ignatiuk ◽  
Mariusz Grabiec ◽  
Leszek Kolondra ◽  
Michał Laska ◽  
...  
Keyword(s):  
Mass Balance ◽  
Digital Elevation Models ◽  
Control Point ◽  
Aerial Photographs ◽  
Differential Gps ◽  
Tidewater Glaciers ◽  
Digital Elevation ◽  
High Resolution Satellite Images ◽  
Elevation Changes ◽  
Geodetic Mass Balance

In this study, we assess the accuracy and precision of digital elevation models (DEM) retrieved from aerial photographs taken in 2011 and from Very High Resolution satellite images (WorldView-2 and Pléiades) from the period 2012–2017. Additionally, the accuracy of the freely available Strip product of ArcticDEM was verified. We use the DEMs to characterize geometry changes over Hansbreen and Hornbreen, two tidewater glaciers in southern Spitsbergen, Svalbard. The satellite-based DEMs from WorldView-2 and Pléiades stereo pairs were processed using the Rational Function Model (RFM) without and with one ground control point. The elevation quality of the DEMs over glacierized areas was validated with in situ data: static differential GPS survey of mass balance stakes and GPS kinematic data acquired during ground penetrating radar survey. Results demonstrate the usefulness of the analyzed sources of DEMs for estimation of the total geodetic mass balance of the Svalbard glaciers. DEM accuracy is sufficient to investigate glacier surface elevation changes above 1 m. Strips from the ArcticDEM are generally precise, but some of them showed gross errors and need to be handled with caution. The surface of Hansbreen and Hornbreen has been lowering in recent years. The average annual elevation changes for Hansbreen were more negative in the period 2015–2017 (−2.4 m a−1) than in the period 2011–2015 (−1.7 m a−1). The average annual elevation changes over the studied area of Hornbreen for the period 2012–2017 amounted to −1.6 m a−1. The geodetic mass balance for Hansbreen was more negative than the climatic mass balance estimated using the mass budget method, probably due to underestimation of the ice discharge. From 2011 to 2017, Hansbreen lost on average over 1% of its volume each year. Such a high rate of relative loss illustrates how fast these glaciers are responding to climate change.

scholarly journals Spatio-Temporal Changes of Mass Balance in the Ablation Area of the Muz Taw Glacier, Sawir Mountains, from Multi-Temporal Terrestrial Geodetic Surveys

2021 ◽  
Vol 13 (8) ◽  
pp. 1465
Author(s):  
Chunhai Xu ◽  
Zhongqin Li ◽  
Feiteng Wang ◽  
Jianxin Mu
Keyword(s):  
Mass Balance ◽  
Glacier Surface ◽  
Surface Evolution ◽  
Ablation Area ◽  
Glacier Terminus ◽  
Freshwater Resource ◽  
Multi Temporal ◽  
Elevation Changes ◽  
Negative Surface ◽  
Spatio Temporal

The glaciers in the Sawir Mountains are an important freshwater resource, and glaciers have been experiencing a continuing retreat over the past few decades. However, studies on detailed glacier mass changes are currently sparse. Here, we present the high-precision evolution of annual surface elevation and geodetic mass changes in the ablation area of the Muz Taw Glacier (Sawir Mountains, China) over the latest three consecutive mass-balance years (2017–2020) based on multi-temporal terrestrial geodetic surveys. Our results revealed clearly surface lowering and negative geodetic mass changes, and the spatial changing patterns were generally similar for the three periods with the most negative surface lowering (approximately −5.0 to −4.0 m a−1) around the glacier terminus. The gradient of altitudinal elevation changes was commonly steep at the low elevations and gentle in the upper-elevation parts, and reduced surface lowering was observed at the glacier terminus. Resulting emergence velocities ranged from 0.11 to 0.86 m a−1 with pronounced spatial variability, which was mainly controlled by surface slope, ice thickness, and the movement of tributary glaciers. Meanwhile, emergence velocities slightly compensated the surface ablation at the ablation area with a proportion of 14.9%, and dynamic thickening had small contributions to glacier surface evolution. Limited annual precipitation and glacier accumulation may result in these weak contributions. Higher-resolution surveys at the seasonal and monthly scales are required to get insight into the mass balance processes and their mechanism.

scholarly journals Estimation of volume changes of mountain glaciers from ICESat data: an example from the Aletsch Glacier, Swiss Alps

2013 ◽  
Vol 7 (4) ◽  
pp. 3261-3291 ◽  
Author(s):  
J. Kropáček ◽  
N. Neckel ◽  
A. Bauder
Keyword(s):  
Mass Balance ◽  
Statistical Approach ◽  
Swiss Alps ◽  
Surface Elevation ◽  
Linear Change ◽  
Glacier Surface ◽  
Ablation Area ◽  
Mountain Glaciers ◽  
Ice Cloud ◽  
Elevation Changes

Abstract. Worldwide estimation of recent changes in glacier volume is challenging, but becomes more feasible with the help of present and future remote sensing missions. NASA's Ice Cloud and Elevation Satellite (ICESat) mission provides accurate elevation estimates derived from the two way travel time of the emitted laser pulse. In this study two different methods were employed for derivation of surface elevation changes from ICESat records on example of the Aletsch Glacier. A statistical approach relies on elevation differences of ICESat points to a reference DEM while an analytical approach compares spatially similar ICESat tracks. Using the statistical approach, in the upper and lower parts of the ablation area, the surface lowering was found to be from −2.1 ± 0.15 m yr−1 to −2.6 ± 0.10 m yr−1 and from −3.3 ± 0.36 m yr−1 to −5.3 ± 0.39 m yr−1, respectively, depending on the DEM used. Employing the analytical method, the surface lowering in the upper part of the ablation area was estimated as −2.5 ± 1.3 m yr−1 between 2006 and 2009. In the accumulation area both methods revealed no significant trend. The trend in surface lowering derived by the statistical method allows an estimation of the mean mass balance in the period 2003–2009 assuming constant ice density and a linear change of glacier surface lowering with altitude in the ablation area. The resulting mass balance was validated by a comparison to another geodetic approach based on the subtraction of two DEMs for the years 2000 and 2009. We conclude that ICESat data is a valid source of information on surface elevation changes and on mass balance of mountain glaciers.

scholarly journals Surface elevation changes on Lachman Crags ice caps (north-eastern Antarctic Peninsula) since 1979 indicated by DEMs and ICESat data

2019 ◽  
Vol 65 (251) ◽  
pp. 410-421 ◽  
Author(s):  
ZBYNĚK ENGEL ◽  
JAN KROPÁČEK ◽  
JANA SMOLÍKOVÁ
Keyword(s):  
20Th Century ◽  
Antarctic Peninsula ◽  
Surface Elevation ◽  
Aerial Photographs ◽  
Altimeter Data ◽  
Glacier Surface ◽  
Ice Caps ◽  
North Eastern ◽  
Elevation Changes ◽  
The Antarctic

ABSTRACTThe long-term warming on the Antarctic Peninsula in the second half of the 20th century prompted rapid retreat of glaciers on the peninsula and surrounding islands. Retreat accelerated until the beginning of the new millennium when the regional warming trend significantly decreased. The response of glaciers to the change in temperature trend has been observed around the northern part of the Antarctic Peninsula but the timing of the shift from the surface lowering to mass gain remains unclear. Using historical aerial photographs, DEMs and satellite altimeter data from ICESat, we estimate areal and surface elevation changes of two small ice caps in the northern part of James Ross Island over the last 39 years. The glacierized area on Lachman Crags decreased from 4.337 ± 0.037 to 3.581 ± 0.014 km2 (−17.4%) between 1979 and 2006 and then increased to 3.597 ± 0.047 km2 (0.4%) until 2016. Surface lowering observed on ice caps after 1979 continued at least until 2008 as indicated by the ICESat data. The change from the lowering trend to increase in glacier surface elevation probably occurred after the ablation season 2008/09, which ranks among the warmest summers in the north-eastern Antarctic Peninsula since the mid-20th century.

scholarly journals No significant mass loss in the glaciers of Astore Basin (North-Western Himalaya), between 1999 and 2016

2019 ◽  
Vol 65 (250) ◽  
pp. 270-278 ◽  
Author(s):  
SHER MUHAMMAD ◽  
LIDE TIAN ◽  
MARCUS NÜSSER
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Thermal Emission ◽  
Western Himalaya ◽  
Surface Elevation ◽  
High Mountain ◽  
Differential Gps ◽  
Average Mass ◽  
Elevation Changes ◽  
Geodetic Mass Balance

ABSTRACTAlthough glaciers in High Mountain Asia produce an enormous amount of water used by downstream populations, they remain poorly observed in the field. This study presents a geodetic mass balance of the glaciers in the Astore Basin (with differential GPS (dGPS) measurements on Harcho glacier) between 1999 and 2016. Changes near the terminus of Harcho glacier (below 3800 m a.s.l.) featured heterogeneous surface elevation changes, whereas the middle section shows the most negative changes. The surface elevation changes were positive above 4200 m a.s.l. The average annual mass balance was −0.08 ± 0.07 m w.e. a−1 derived from a dGPS and DEM comparison whereas Advanced Spaceborne Thermal Emission and Reflection Radiometer DEM-based results show a slightly positive, that is 0.03 ± 0.24 m w.e. a−1 in the same period. In contrast, the terminus indicates a substantial retreat of ~368 m (4.5 m a−1) between 1934 and 2016. The average mass balance of 19 glaciers (>2 km2) covering ~60% of the total glaciers in the Basin exhibit no net mass loss in the period of 2000−2016 and follow a pattern similar to adjacent Karakoram glaciers.

The new Swiss Glacier Inventory SGI2016: a detailed cartographic representation of Swiss glacier extent and supraglacial debris-cover

2021 ◽  
Author(s):  
Andreas Linsbauer ◽  
Matthias Huss ◽  
Elias Hodel ◽  
Andreas Bauder ◽  
Mauro Fischer ◽  
...  
Keyword(s):  
Surface Area ◽  
Swiss Alps ◽  
Aerial Images ◽  
Aerial Photographs ◽  
Slope Aspect ◽  
Relative Area ◽  
Glacier Surface ◽  
Glacier Inventory ◽  
Digital Elevation ◽  
Debris Cover

<p>With increasing anthropogenic greenhouse gas emissions and corresponding global warming, glaciers in Switzerland are shrinking rapidly as in many mountain ranges on Earth. Repeated glacier inventories are a key task to monitor such glacier changes and provide detailed information on the extent of glaciation, and important parameters such as area, elevation range, slope, aspect etc. for a given point or a period in time. Here we present the new Swiss Glacier Inventory (SGI2016) that has been acquired based on high-resolution aerial imagery and digital elevation models in cooperation with the Federal Office of Topography (swisstopo) and Glacier Monitoring in Switzerland (GLAMOS), bringing together topological and glaciological knowhow. We define the process, workflow and required glaciological adaptations to compile a highly accurate glacier inventory based on the digital Swiss topographic landscape model (swissTLM<sup>3D</sup>).</p><p>The SGI2016 provides glacier outlines (areas), supraglacial debris cover, ice divides and location points of all glaciers in Switzerland referring to the years 2013-2018, whereas most of the glacier outlines have been mapped based on aerial images acquired between 2015-2017 (75% in number and 87% in area), with the centre year 2016. The SGI2016 maps 1400 individual glacier entities with a total glacier surface area of 961 km<sup>2</sup> (whereof 11% / 104 km<sup>2</sup> are debris-covered) and constitutes the so far most detailed cartographic representation of glacier extent in Switzerland. Analysing the dependencies between topographic parameters and debris-cover fraction on the basis of individual glaciers reveals that short glaciers with a moderate mean slope and glaciers with a low median elevation tend to have high debris fractions. A change assessment between the SGI1973 and SGI2016 based on individual glacier entities affirms the largest relative area changes for small glaciers and for low-elevation glaciers, whereas the largest glaciers show small relative area changes, though large absolute changes. The analysis further indicates a tendency for glaciers with a high share of supraglacial debris to show larger relative area changes.</p><p>Despite of an observed strong glacier volume loss between 2010 and 2016, the total glacier surface area of the SGI2016 is somewhat larger than reported in the last Swiss glacier inventory SGI2010. Even though both inventories were created based on swisstopo aerial photographs, the additional data, tools, resources and methodologies used by the professional cartographers digitizing glacier outlines in 3D for the SGI2016, are able to explain the counter-intuitive difference between SGI2010 and SGI2016. A direct comparison of these two datasets is thus not meaningful, but an experiment where a representative glacier sample of the SGI2010 was re-assessed based on the approaches of the SGI2016 led to an upscaled total glacier surface area of 1010 km<sup>2</sup> for the Swiss Alps around 2010. This indicates an area loss of 49 km<sup>2</sup> between the two last Swiss glacier inventories. As swisstopo data products are and will be regularly updated, the SGI2016 is the first step towards a consistent and accurate data product of repeated glacier inventories in six-year time intervals that promises a high comparability for individual glaciers and glacier samples.</p>

scholarly journals Unravelling the evolution of Zmuttgletscher and its debris cover since the end of the Little Ice Age

2019 ◽  
Vol 13 (7) ◽  
pp. 1889-1909 ◽  
Author(s):  
Nico Mölg ◽  
Tobias Bolch ◽  
Andrea Walter ◽  
Andreas Vieli
Keyword(s):  
Mass Balance ◽  
Ice Age ◽  
Aerial Photographs ◽  
Dynamic Interactions ◽  
Glacier Surface ◽  
Ablation Area ◽  
Debris Cover ◽  
Historic Maps ◽  
Length And Area ◽  
Flow Velocities

Abstract. Debris-covered glaciers generally exhibit large, gently sloping, slow-flowing tongues. At present, many of these glaciers show high thinning rates despite thick debris cover. Due to the lack of observations, most existing studies have neglected the dynamic interactions between debris cover and glacier evolution over longer time periods. The main aim of this study is to reveal such interactions by reconstructing changes of debris cover, glacier geometry, flow velocities, and surface features of Zmuttgletscher (Switzerland), based on historic maps, satellite images, aerial photographs, and field observations. We show that debris cover extent has increased from ∼13 % to ∼32 % of the total glacier surface since 1859 and that in 2017 the debris is sufficiently thick to reduce ablation compared to bare ice over much of the ablation area. Despite the debris cover, the glacier-wide mass balance of Zmuttgletscher is comparable to that of debris-free glaciers located in similar settings, whereas changes in length and area have been small and delayed by comparison. Increased ice mass input in the 1970s and 1980s resulted in a temporary velocity increase, which led to a local decrease in debris cover extent, a lowering of the upper boundary of the ice-cliff zone, and a strong reduction in ice-cliff area, indicating a dynamic link between flow velocities, debris cover, and surface morphology. Since 2005, the lowermost 1.5 km of the glacier has been quasi-stagnant, despite a slight increase in the surface slope of the glacier tongue. We conclude that the long-term glacier-wide mass balance is mainly governed by climate. The debris cover governs the spatial pattern of elevation change without changing its glacier-wide magnitude, which we explain by the extended ablation area and the enhanced thinning in regions with thin debris further up-glacier and in areas with abundant meltwater channels and ice cliffs. At the same time rising temperatures lead to increasing debris cover and decreasing ice flux, thereby attenuating length and area losses.

scholarly journals Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard), investigated by ground penetrating radar

2011 ◽  
Vol 5 (1) ◽  
pp. 139-149 ◽  
Author(s):  
K. Bælum ◽  
D. I. Benn
Keyword(s):  
Ground Penetrating Radar ◽  
Thermal Structure ◽  
Drainage System ◽  
High Arctic ◽  
Differential Gps ◽  
Glacier Surface ◽  
Digital Elevation ◽  
Drainage Channels ◽  
Ground Penetrating ◽  
Subglacial Drainage

Abstract. Proglacial icings accumulate in front of many High Arctic glaciers during the winter months, as water escapes from englacial or subglacial storage. Such icings have been interpreted as evidence for warm-based subglacial conditions, but several are now known to occur in front of cold-based glaciers. In this study, we investigate the drainage system of Tellbreen, a 3.5 km long glacier in central Spitsbergen, where a large proglacial icing develops each winter, to determine the location and geometry of storage elements. Digital elevation models (DEMs) of the glacier surface and bed were constructed using maps, differential GPS and ground penetrating radar (GPR). Rates of surface lowering indicate that the glacier has a long-term mass balance of −0.6 ± 0.2 m/year. Englacial and subglacial drainage channels were mapped using GPR, showing that Tellbreen has a diverse drainage system that is capable of storing, transporting and releasing water year round. In the upper part of the glacier, drainage is mainly via supraglacial channels. These transition downglacier into shallow englacial "cut and closure" channels, formed by the incision and roof closure of supraglacial channels. Below thin ice near the terminus, these channels reach the bed and contain stored water throughout the winter months. Even though no signs of temperate ice were detected and the bed is below pressure-melting point, Tellbreen has a surface-fed, channelized subglacial drainage system, which allows significant storage and delayed discharge.

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