scholarly journals Interannual and Seasonal Variability of Glacier Surface Velocity in the Parlung Zangbo Basin, Tibetan Plateau

2020 ◽  
Vol 13 (1) ◽  
pp. 80
Author(s):  
Jing Zhang ◽  
Li Jia ◽  
Massimo Menenti ◽  
Shaoting Ren
Keyword(s):  
Seasonal Variability ◽  
Global Climate ◽  
Meteorological Data ◽  
Transverse Velocity ◽  
Surface Velocity ◽  
Landsat 8 ◽  
Velocity Change ◽  
Glacier Surface ◽  
Glacier Velocity ◽  
Glacier Flow

Monitoring glacier flow is vital to understand the response of mountain glaciers to environmental forcing in the context of global climate change. Seasonal and interannual variability of surface velocity in the temperate glaciers of the Parlung Zangbo Basin (PZB) has attracted significant attention. Detailed patterns in glacier surface velocity and its seasonal variability in the PZB are still uncertain, however. We utilized Landsat-8 (L8) OLI data to investigate in detail the variability of glacier velocity in the PZB by applying the normalized image cross-correlation method. On the basis of satellite images acquired from 2013 to 2020, we present a map of time-averaged glacier surface velocity and examined four typical glaciers (Yanong, Parlung No.4, Xueyougu, and Azha) in the PZB. Next, we explored the driving factors of surface velocity and of its variability. The results show that the glacier centerline velocity increased slightly in 2017–2020. The analysis of meteorological data at two weather stations on the outskirts of the glacier area provided some indications of increased precipitation during winter-spring. Such increase likely had an impact on ice mass accumulation in the up-stream portion of the glacier. The accumulated ice mass could have caused seasonal velocity changes in response to mass imbalance during 2017–2020. Besides, there was a clear winter-spring speedup of 40% in the upper glacier region, while a summer speedup occurred at the glacier tongue. The seasonal and interannual velocity variability was captured by the transverse velocity profiles in the four selected glaciers. The observed spatial pattern and seasonal variability in glacier surface velocity suggests that the winter-spring snow might be a driver of glacier flow in the central and upper portions of glaciers. Furthermore, the variations in glacier surface velocity are likely related to topographic setting and basal slip caused by the percolation of rainfall. The findings on glacier velocity suggest that the transfer of winter-spring accumulated ice triggered by mass conservation seems to be the main driver of changes in glacier velocity. The reasons that influence the seasonal surface velocity change need further investigation.

Remote sensing flow velocity of debris-covered glaciers using Landsat 8 data

2015 ◽  
Vol 40 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Lydia Sam ◽  
Anshuman Bhardwaj ◽  
Shaktiman Singh ◽  
Rajesh Kumar
Keyword(s):  
Remote Sensing ◽  
Flow Velocity ◽  
Accuracy Assessment ◽  
Geographical Area ◽  
Surface Flow ◽  
Velocity Estimation ◽  
Surface Velocity ◽  
Landsat 8 ◽  
Glacier Surface ◽  
Glacier Velocity

Changes in ice velocity of a glacier regulate its mass balance and dynamics. The estimation of glacier flow velocity is therefore an important aspect of temporal glacier monitoring. The utilisation of conventional ground-based techniques for detecting glacier surface flow velocity in the rugged and alpine Himalayan terrain is extremely difficult. Remote sensing-based techniques can provide such observations on a regular basis for a large geographical area. Obtaining freely available high quality remote sensing data for the Himalayan regions is challenging. In the present work, we adopted a differential band composite approach, for the first time, in order to estimate glacier surface velocity for non-debris and supraglacial debris covered areas of a glacier, separately. We employed various bandwidths of the Landsat 8 data for velocity estimation using the COSI-Corr (co-registration of optically sensed images and correlation) tool. We performed the accuracy assessment with respect to field measurements for two glaciers in the Indian Himalaya. The panchromatic band worked best for non-debris parts of the glaciers while band 6 (SWIR – short wave infrared) performed best in case of debris cover. We correlated six temporal Landsat 8 scenes in order to ensure the performance of the proposed algorithm on monthly as well as yearly timescales. We identified sources of error and generated a final velocity map along with the flow lines. Over- and underestimates of the yearly glacier velocity were found to be more in the case of slow moving areas with annual displacements less than 5 m. Landsat 8 has great capabilities for such velocity estimation work for a large geographic extent because of its global coverage, improved spectral and radiometric resolutions, free availability and considerable revisit time.

scholarly journals Spatio-temporal variations in glacier surface velocity in the Himalayas

2021 ◽  
Author(s):  
Yu Zhou ◽  
Jianlong Chen ◽  
Xiao Cheng
Keyword(s):  
Mass Loss ◽  
Temporal Variations ◽  
Surface Velocity ◽  
Glacier Surface ◽  
Environmental Forcing ◽  
Landsat 7 ◽  
Spatio Temporal ◽  
Velocity Changes ◽  
Glacier Velocity ◽  
Glacier Flow

Abstract. Glacier evolution with time provides important information about climate variability. Here we investigate glacier surface velocity in the Himalayas and analyse the patterns of glacier flow. We collect 220 scenes of Landsat-7 panchromatic images between 1999 and 2000, and Sentinel-2 panchromatic images between 2017 and 2018, to calculate surface velocities of 36,722 glaciers during these two periods. We then derive velocity changes between 1999 and 2018, based on which we perform a detailed analysis of motion of each individual glacier, and noted that the changes are spatially heterogeneous. Of all the glaciers, 32 % have speeded up, 24.5 % have slowed down, and the rest 43.5 % remained stable. The amplitude of glacier slowdown, as a result of glacier mass loss, is remarkably larger than that of speedup. At regional scales, we found that glacier surface velocity in winter has uniformly decreased in the western part of the Himalayas between 1999 and 2018, whilst increased in the eastern part; this contrasting difference may be associated with decadal changes in accumulation and/or melting under different climatic regimes. We also found that the overall trend of surface velocity exhibits seasonal variability: summer velocity changes are positively correlated with mass loss, whereas winter velocity changes show a negative correlation. Our study suggests that glacier velocity changes in the Himalayas are more spatially and temporally heterogeneous than previously thought, emphasising complex interactions between glacier dynamics and environmental forcing.

scholarly journals Long-Term Deceleration of Glaciers in the Eastern Nyainqentanglha Mountains, Southeastern Tibetan Plateau, Revealed from Landsat Images

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2387 ◽  
Author(s):  
Xiyou Fu ◽  
Jianmin Zhou
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Significant Rise ◽  
Surface Velocity ◽  
Landsat Images ◽  
Glacier Surface ◽  
Temperature And Precipitation ◽  
Glacier Velocity ◽  
The Relationship

Temperate glaciers are very sensitive to variations in temperature and precipitation, and thus represent a good indicator of climate change. By exploiting complete Landsat archives during periods of 1988–1990, 2000–2002 and 2014–2016, we derived three velocity maps of the temperate glaciers on the eastern Nyainqêntanglha Mountains in southeastern Tibetan to reveal the long-term changes of glacier surface velocity. Our results show that all the investigated glaciers experienced deceleration, with rates of deceleration varying from 4.15% to 29.8% per decade during the period from 1988–1990 to 2014–2016, showing heterogeneous deceleration patterns. A significant rise in temperature and an insignificant decrease in precipitation was found from the meteorological data of the nearby meteorological station. The region-wide deceleration of glaciers was, thus, attributed to the negative mass balance induced mainly by the rise in temperature. The averaged rates of deceleration for periods from 1988–1990 to 2000–2002 and from 2000–2002 to 2014–2016 are 20.97% and 22.02% per decade, respectively, indicating a nearly even speed of deceleration in velocities during study periods. The nearly even speed of deceleration in velocities and the accelerating mass loss trend from periods before the 2000s to after the 2000s highlighted the complexity of the relationship between mass balance and glacier velocity.

scholarly journals Glacier Velocity Changes in the Himalayas in Relation to Ice Mass Balance

2021 ◽  
Vol 13 (19) ◽  
pp. 3825
Author(s):  
Yu Zhou ◽  
Jianlong Chen ◽  
Xiao Cheng
Keyword(s):  
Mass Loss ◽  
Surface Velocity ◽  
Winter Period ◽  
Glacier Surface ◽  
Environmental Forcing ◽  
Complex Interactions ◽  
Landsat 7 ◽  
Velocity Changes ◽  
Glacier Velocity ◽  
Glacier Flow

Glacier evolution with time provides important information about climate variability. Here, we investigated glacier velocity changes in the Himalayas and analysed the patterns of glacier flow. We collected 220 scenes of Landsat-7 panchromatic images between 1999 and 2000, and Sentinel-2 panchromatic images between 2017 and 2018, to calculate surface velocities of 36,722 glaciers during these two periods. We then derived velocity changes between 1999 and 2018 for the early winter period, based on which we performed a detailed analysis of motion of each individual glacier, and noted that the changes are spatially heterogeneous. Of all the glaciers, 32% have sped up, 24.5% have slowed down, and the rest 43.5% have remained stable. The amplitude of glacier slowdown, as a result of glacier mass loss, is significantly larger than that of speedup. At regional scales, we found that glacier surface velocity in winter has uniformly decreased in the western part of the Himalayas between 1999 and 2018, while increased in the eastern part; this contrasting difference may be associated with decadal changes in accumulation and/or melting under different climatic regimes. We also found that the overall trend of surface velocity exhibits seasonal variability: summer velocity changes are positively correlated with mass loss, i.e., velocity increases with increasing mass loss, whereas winter velocity changes show a negative correlation. Our study suggests that glacier velocity changes in the Himalayas are spatially and temporally heterogeneous, in agreement with studies that previously highlighted this trend, emphasising complex interactions between glacier dynamics and environmental forcing.

scholarly journals SenDiT: The Sentinel-2 Displacement Toolbox with Application to Glacier Surface Velocities

2019 ◽  
Vol 11 (10) ◽  
pp. 1151
Author(s):  
Teodor Nagy ◽  
Liss M. Andreassen ◽  
Robert A. Duller ◽  
Pablo J. Gonzalez
Keyword(s):  
Feature Tracking ◽  
World Wide ◽  
Satellite Images ◽  
Glacier Surface ◽  
Displacement Maps ◽  
Spatial And Temporal Changes ◽  
Glacier Velocity ◽  
Glacier Flow ◽  
Sentinel 2A ◽  
Sentinel 2

Satellite imagery represents a unique opportunity to quantify the spatial and temporal changes of glaciers world-wide. Glacier velocity has been measured from repeat satellite scenes for decades now, yet a range of satellite missions, feature tracking programs, and user approaches have made it a laborious task. To date, there has been no tool developed that would allow a user to obtain displacement maps of any specified glacier simply by establishing the key temporal, spatial and feature tracking parameters. This work presents the application and development of a unique, semi-automatic, open-source, flexible processing toolbox for the retrieval of displacement maps with a focus on obtaining glacier surface velocities. SenDiT combines the download, pre-processing, feature tracking, and postprocessing of the highest resolution Sentinel-2A and Sentinel-2B satellite images into a semi-automatic toolbox, leaving a user with a set of rasterized and georeferenced glacier flow magnitude and direction maps for their further analyses. The solution is freely available and is tailored so that non-glaciologists and people with limited geographic information system (GIS) knowledge can also benefit from it. The system can be used to provide both regional and global sets of ice velocities. The system was tested and applied on a range of glaciers in mainland Norway, Iceland, Greenland and New Zealand. It was also tested on areas of stable terrain in Libya and Australia, where sources of error involved in the feature tracking using Sentinel-2 imagery are thoroughly described and quantified.

Gradual build up and episodic character of glacier velocity preceding and during the surge of a Karakorum glacier enabled by open-access image-processing

2020 ◽  
Author(s):  
Ian Delaney ◽  
Saif Aati ◽  
Flavian Beaud ◽  
Shan Gremion ◽  
Surendra Adhikari ◽  
...  
Keyword(s):  
Open Access ◽  
Landsat 8 ◽  
Optical Remote Sensing ◽  
Lake Formation ◽  
Glacier Dynamics ◽  
Current Availability ◽  
Spatio Temporal ◽  
Glacier Velocity ◽  
Glacier Flow

<p>Glacier surging provides a unique opportunity to examine rapid changes in glacier sliding that occur when some glaciers alternate between slower-than-normal (quiescence) and faster-than-normal (surge) velocities. On surging glaciers, mechanical instabilities within the glacier set off a regime of fast glacier flow, which causes these glaciers to accelerate and advance. The precise processes that cause a surging remain uncertain and likely vary between glaciers. However, the uptake of studies on glacier surging over the past decade continues to yield invaluable insights in glacier dynamics. In this study, we combine optical remote sensing and numerical modeling to examine the recent surge of Shishper glacier, in the Pakistani Karakorum. This glacier started surging in 2018, showed a dramatic terminus advance that reached rates of several meters per day. In the process, it dammed the adjacent valley, forming a lake which drained in June 2019 flooding the downstream valley, damaging the Karakorum Highway and threatening nearby communities. We leverage a high spatio-temporal resolution dataset of glacier velocities, using roughly 100 open-access images, across the Landsat-8 and Sentinel-2 record, thus encompassing the quiescence (2013-2018) and surge (2018-2019) phases. We created the dataset in an updated and nearly automated workflow by using the COSI-Corr software package to calculate displacements between images combined with a unique algorithm to filter data and remove artifacts. The result consists in high-resolution velocity maps with resolution with time intervals as short as five days. Such dataset provide a complete time-series of the spatio-temporal evolution of ice-surface velocities during a surge. One of the most notable finding is that the surge onset occurs progressively. In the two years leading up to the surge, spring speed-ups became increasingly larger in than the long-term median. We further identify three periods with  surge velocities far higher than the long-term median that likely coincide with hydrological events. Two periods occur in the spring (2018 and 2019) and the third corresponds with the lake formation in the winter of 2018-2019. Finally, we establish that the surge termination coincided with the lake drainage at the end of June 2019. The current availability of open-access imagery and  glacier topography allow us to  make an increased quantity of observations and thus better quantify glacier dynamics.</p>

scholarly journals Properties of Debris-Laden Ice: Application to the Flow Response of the Glaciers on Mount St Helens

1983 ◽  
Vol 4 ◽  
pp. 297 ◽  
Author(s):  
Melinda M. Brugman
Keyword(s):  
Flow Behavior ◽  
Transverse Velocity ◽  
Plug Flow ◽  
Sudden Change ◽  
Velocity Profiles ◽  
Pyroclastic Flows ◽  
Surface Velocity ◽  
Vertical Profiles ◽  
Glacier Surface ◽  
Mount St Helens

Intense deformation within an extensive englacial debris layer appears to be a dominant flow mechanism for glaciers on Mount St Helens, Washington. Observations of this phenomenon have been made on Shoestring Glacier and more recently on other glaciers on the volcano. Transverse velocity profiles on Shoestring Glacier have shown a marked plug flow behavior occurring between narrow marginal zones of crevassing. Both longitudinal and transverse velocity profiles on Shoestring Glacier were measured during the year before and the two years after the cataclysmic eruption of the volcano on 18 May 1980. The geometry and regime of every glacier on Mount St Helens dramatically changed during the eruption. The entire accumulation area of Shoestring Glacier was removed by a volcanic landslide and blast, and the glacier surface was deeply incised through the action of pyroclastic flows and mudflows. Surface velocity measurements were supplemented by vertical profiles taken along the newly exposed ice cliffs. Large velocity gradients seen in the transverse, longitudinal and vertical profiles coincided with the mapped location of a recently exposed englacial debris layer. Further detailed measurements on the vertical profiles show that the intense shear occurs by deformation internal to the debris layer, A study of the properties of debris-laden ice was undertaken to determine the mechanism for localization of deformation to the debris layer and for the associated response of the glacier to a sudden change in stress.

scholarly journals Properties of Debris-Laden Ice: Application to the Flow Response of the Glaciers on Mount St Helens

1983 ◽  
Vol 4 ◽  
pp. 297-297 ◽  
Author(s):  
Melinda M. Brugman
Keyword(s):  
Flow Behavior ◽  
Transverse Velocity ◽  
Plug Flow ◽  
Sudden Change ◽  
Velocity Profiles ◽  
Pyroclastic Flows ◽  
Surface Velocity ◽  
Vertical Profiles ◽  
Glacier Surface ◽  
Mount St Helens

Intense deformation within an extensive englacial debris layer appears to be a dominant flow mechanism for glaciers on Mount St Helens, Washington. Observations of this phenomenon have been made on Shoestring Glacier and more recently on other glaciers on the volcano. Transverse velocity profiles on Shoestring Glacier have shown a marked plug flow behavior occurring between narrow marginal zones of crevassing. Both longitudinal and transverse velocity profiles on Shoestring Glacier were measured during the year before and the two years after the cataclysmic eruption of the volcano on 18 May 1980.The geometry and regime of every glacier on Mount St Helens dramatically changed during the eruption. The entire accumulation area of Shoestring Glacier was removed by a volcanic landslide and blast, and the glacier surface was deeply incised through the action of pyroclastic flows and mudflows. Surface velocity measurements were supplemented by vertical profiles taken along the newly exposed ice cliffs. Large velocity gradients seen in the transverse, longitudinal and vertical profiles coincided with the mapped location of a recently exposed englacial debris layer. Further detailed measurements on the vertical profiles show that the intense shear occurs by deformation internal to the debris layer, A study of the properties of debris-laden ice was undertaken to determine the mechanism for localization of deformation to the debris layer and for the associated response of the glacier to a sudden change in stress.

scholarly journals Summer Mass Balance and Surface Velocity Derived by Unmanned Aerial Vehicle on Debris-Covered Region of Baishui River Glacier No. 1, Yulong Snow Mountain

2020 ◽  
Vol 12 (20) ◽  
pp. 3280 ◽  
Author(s):  
Yanjun Che ◽  
Shijin Wang ◽  
Shuhua Yi ◽  
Yanqiang Wei ◽  
Yancong Cai
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
Global Climate ◽  
Surface Velocity ◽  
Dynamic Features ◽  
Glacier Surface ◽  
Glacier Melting ◽  
Western Kunlun ◽  
The Mean ◽  
Yulong Snow Mountain

Glacier retreat is a common phenomenon in the Qinghai-Tibetan Plateau (QTP) with global warming during the past several decades, except for several mountains, such as the glaciers in the Karakoram and the western Kunlun Mountains. The dynamic nature of glaciers significantly influences the hydrologic, geologic, and ecological systems in the mountain regions. The sensitivity and dynamic response to climate change make glaciers excellent indicators of regional and global climate change, such as glacier melting and retreat with the rise of local air temperature. Long-term monitoring of glacier change is important to understand and assess past, current, and possible future climate environments. Some glacier surfaces are safe and accessible by foot, and are monitored using mass balance stakes and snow pits. Meanwhile, some glaciers with inaccessible termini may be surveyed using satellite remote images and Unmanned Aerial Vehicles (UAVs). Those inaccessible glaciers are generally covered by debris in the southeast QTP, which is hardly accessible due to the wide distribution of crevasses and cliffs. In this paper, we used the UAV to monitor the dynamic features of mass balance and velocity of the debris-covered region of Baishui River Glacier No. 1 (BRG1) on the Yulong Snow Mountain (YSM), Southeast QTP. We obtained the Orthomosaic and DEM with a high resolution of 0.10 m on 20 May and 22 September 2018, respectively. The comparison showed that the elevation of the debris-covered region of the BRG1 decreased by 6.58 m ± 3.70 m on average, and the mean mass balance was −5.92 m w.e. ± 3.33 m w.e. during the summer, correspondingly. The mean displacement of debris-covered glacier surface was 18.30 m ± 6.27 m, that is, the mean daily velocity was 0.14 m/d ± 0.05 m/d during the summer. In addition, the UAV images not only revealed the different patterns of glacier melting and displacement but also captured the phenomena of mass loss due to ice avalanches at the glacier front and the development of large crevasses. This study provides a feasible method for understanding the dynamic features of global debris-covered glaciers which are inaccessible and unobservable by other means.

scholarly journals Modeling the WorldView-derived seasonal velocity evolution of Kennicott Glacier, Alaska

2016 ◽  
Vol 62 (234) ◽  
pp. 763-777 ◽  
Author(s):  
W. H. ARMSTRONG ◽  
R. S. ANDERSON ◽  
JEFFERY ALLEN ◽  
H. RAJARAM
Keyword(s):  
Stress Gradient ◽  
Surface Expression ◽  
Surface Velocity ◽  
Cross Sectional ◽  
Ice Surface ◽  
Hydrologic System ◽  
Glacier Velocity ◽  
Glacier Flow ◽  
Insight Into ◽  
Gaining Insight

ABSTRACTGlacier basal motion generates diurnal to multi-annual fluctuations in glacier velocity and mass flux. Understanding these fluctuations is important for prediction of future sea-level rise and for gaining insight into glacier physics and erosion. Here, we derive glacier velocity through cross-correlation of WorldView satellite imagery to document the evolution of ice surface velocity on Kennicott Glacier, Alaska, over the 2013 melt season. The summer speedup is spatially uniform over a ~12 km2 area, over which the spring velocity varies significantly. Velocity increases by 1.4-fold to tenfold across the study domain, with larger values where spring velocities are low. To investigate the cross-glacier distribution of basal motion required to explain the observed surface speedup, we employ a two-dimensional cross-sectional glacier flow model. We find the model is insensitive to the spatial distribution of basal slip because stress gradient ice coupling diffuses the surface expression of the basal velocity field. While the temporal evolution of the subglacial hydrologic system is critical for predicting a glacier's response to meltwater inputs, our work suggests that glacier and ice-sheet models do not require a detailed representation of subglacial hydrology to accurately capture the spatial pattern of glacier speedup.

Sign in / Sign up

Export Citation Format

Share Document