Seasonal and interannual ice velocity changes of Polar Record Glacier, East Antarctica

AbstractWe present a study of seasonal and interannual ice velocity changes at Polar Record Glacier, East Antarctica, using ERS-1/2, Envisat and PALSAR data with D-InSAR and intensity tracking. Ice flow showed seasonal variations at the front of the glacier tongue. Velocities in winter were 19% less than velocities during summer. No significant interannual changes were detected. Ice velocities in the grounding zone and grounded glacier did not show clear seasonal or interannual changes. The distribution of the seasonal variations suggests that the cause for the changes should be localized. Possible causes are seasonal sea-ice changes and iceberg blocking. Satellite images show that the sea ice surrounding Polar Record Glacier undergoes seasonal changes. Frozen sea ice in winter slowed the huge iceberg, and provided increased resistance to the glacier flow. The interaction between the glacier tongue, iceberg and sea ice significantly influences their flow pattern.

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Processing and analysis of dense ice velocity time series to reconstruct seasonal fluctuations of 3 greenlandic glaciers : Russell Gletscher, Upernavik Isstrom, Petermann Gletscher.

10.5194/egusphere-egu2020-307 ◽

2020 ◽

Author(s):

Anna Derkacheva ◽

Jeremie Mouginot ◽

Romain Millan ◽

Fabien Gillet-Chaulet

Keyword(s):

Time Series ◽

Seasonal Variations ◽

Seasonal Changes ◽

High Temporal Resolution ◽

Landsat 8 ◽

Post Processing ◽

Seasonal Fluctuations ◽

Ice Flow ◽

Ice Velocity ◽

Surface Ice

Significant seasonal changes in ice flow have been reported for outlet glaciers in Greenland. Understanding the mechanisms that control these rapid intra-annual changes in dynamics could potentially help to clarify Greenland's long-term evolution and climate change response.In this study, we investigate seasonal changes in ice flow velocity in order to better understand the processes controlling them. We focus on 3 Greenlandic glaciers of different types: Russell which is a land-terminating glacier with speed ranging from 50 to 350 m/yr,&#160; Upernavik Isstr&#248;m which is a marine-terminating tidewater glacier with speeds up to 4 km/yr, and Petermann Gletscher that has a large ice shelf and with speed at the order of 1 km/yr. Since 2014, the number of spaceborne observations over the ice sheet has increased dramatically with the launch of Landsat-8, Sentinel-1 and -2, providing almost continuous monitoring of glacier dynamics.Here, we develop an automatic processing chain to derive dense time series of surface ice flow from radar sensors, Sentinel -1a/b, and optical sensors, Landsat-7/8 and Sentinel-2, using speckle or feature tracking algorithms. We construct a post-processing analysis based on local polynomial regression to filter our multi-sensor time series and create a velocity database with high temporal resolution and reduced noise. The database allows us to reconstruct the continuous evolution of surface ice velocity with frequency intervals ranging from monthly for the entire glacial basin to weekly for the downstream parts.&#160;Using this methodology, we obtain velocity fields for 4 years between 2015 and 2019 of the entire basins of Russell, Upernavik and Petermann glaciers. Our results clearly show the seasonal variations in flow to which these glaciers are subjected. We analyze the average seasonal fluctuations during the 4 years, as well as particular behavior in different years. These results are then compared and discussed in relation to potential external forcings such as subglacial hydrology (change in basal friction), fluctuations in the ice front or grounding line positions (change in buttressing) and the presence of sea ice or ice melange in front of the glaciers.&#160;Finally, we conclude on the benefits of our post-processing approach for the analysis of dense ice flow time series and provide first insights on the causes of seasonal variations observed on these 3 glaciers.

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Recent variations in the terminus position, ice velocity and surface elevation of Langhovde Glacier, East Antarctica

Antarctic Science ◽

10.1017/s0954102014000364 ◽

2014 ◽

Vol 26 (6) ◽

pp. 636-645 ◽

Cited By ~ 8

Author(s):

Takehiro Fukuda ◽

Shin Sugiyama ◽

Takanobu Sawagaki ◽

Kazuki Nakamura

Keyword(s):

Sea Ice ◽

Flow Velocity ◽

Stable Condition ◽

Field Measurements ◽

East Antarctica ◽

Surface Elevation ◽

Ice Flow ◽

Glacier Terminus ◽

Ice Conditions ◽

Ice Velocity

AbstractTo improve the understanding of the mechanism driving recent changes in outlet glaciers in East Antarctica, we measured changes in the terminus position, ice flow velocity and surface elevation of the Langhovde Glacier located on the Sôya Coast. From satellite images from 2000–12 and field measurements taken in 2012 the glacier terminus position and flow velocity showed little change between 2003 and 2007. After this quiescent period, the glacier progressively advanced by 380 m and the flow velocity increased near the calving front by 10 m a-1 from 2007–10. No significant change was observed in surface elevation during the study period. The changes in the terminus position and flow velocity imply a reduction in the calving rate from 93 m a-1 (2003–07) to 16 m a-1 (2007–10). This suggests that calving was inhibited by stable sea ice conditions in the ocean. Theses results indicate that the Langhovde Glacier was in a relatively stable condition during the study period, and its terminus position was controlled by the rate of calving under the influence of sea ice conditions.

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Monitoring surging glaciers of the Pamirs, central Asia, from space

Annals of Glaciology ◽

10.3189/172756408784700608 ◽

2008 ◽

Vol 48 ◽

pp. 125-134 ◽

Cited By ~ 53

Author(s):

V.M. Kotlyakov ◽

G.B. Osipova ◽

D.G. Tsvetkov

Keyword(s):

Remote Sensing ◽

Central Asia ◽

Satellite Images ◽

Initial Information ◽

Unstable Regime ◽

Landsat 7 ◽

Ice Velocity ◽

Velocity Changes ◽

Academy Of Sciences

AbstractThe evolution of surging glaciers of the Pamirs, central Asia, has been studied using repeat remote-sensing surveys in the Institute of Geography, Russian Academy of Sciences, since the early 1970s. We use images obtained from national Resurs-F satellites (1972–91), as well as Landsat 7 and Terra (1999–2006), to provide a basis for monitoring of surging glaciers, aimed at developing their inventory, studying the causes and mechanisms of surges and examining the timing and extent of glacial catastrophes. The inventory from the early 1990s allows identification of 215 glaciers with a dynamically unstable regime. We discovered 51 surging glaciers. Up until 2006, 10 more surges had occurred. We use stereoscopic deciphering and photogrammetric processing of consecutive satellite images to study the morphology and ice-velocity changes of several compound surging glaciers. We analyze the results of monitoring of Bivachny and Oktyabr’sky glaciers from 1972 to 1991 and Sugran glacier from 1972 to 2006. Two surges of Sugran glacier occurred during this time: an internal surge in 1976–80, and a surge with glacier tongue advance as far as 4.5 km in 2000–05. The role of damming in compound glacier systems is examined. Satellite-based monitoring is now the only method for obtaining initial information about the state and fluctuations of such glaciers.

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Ice flow variations at Polar Record Glacier, East Antarctica

Journal of Glaciology ◽

10.1017/jog.2019.6 ◽

2019 ◽

Vol 65 (250) ◽

pp. 279-287 ◽

Cited By ~ 5

Author(s):

QI LIANG ◽

CHUNXIA ZHOU ◽

IAN M. HOWAT ◽

SEONGSU JEONG ◽

RUIXI LIU ◽

...

Keyword(s):

Seasonal Variations ◽

Back Stress ◽

East Antarctica ◽

Austral Spring ◽

Ice Flow ◽

Ice Shelves ◽

Flow Acceleration ◽

Ice Surface ◽

Flow Speeds ◽

Interannual Fluctuations

ABSTRACTRelatively little is known about the physical mechanisms that drive the dynamics of the East Antarctic outlet glaciers. Here we conduct a remote-sensing investigation of the Polar Record Glacier (PRG), East Antarctica to analyze its ice flow acceleration, ice front variations and ice surface melting. Ice flow speeds at PRG increased by up to 15% from 2005 to 2015, with substantial interannual fluctuations. The ice velocities also showed seasonal variations, accelerating by up to 9% between September and January. Multiple mechanisms contribute to the observed seasonal variations: the initial acceleration may result from the lost back-stress provided by the sea ice in the austral spring and the later speedup relate to the surface meltwater that leads to weakened ice shelf and shear margins. The sensitivity of the PRG to oceanic forcing is confirmed by comparing the secular ice velocity increases with ocean temperatures. These measurements suggest that the dynamics of East Antarctic ice shelves are sensitive to melt at both the surface and base, at a range of timescales.

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Simultaneous disintegration of outlet glaciers in Porpoise Bay (Wilkes Land), East Antarctica, and the long-term speed-up of Holmes Glacier

10.5194/tc-2016-151 ◽

2016 ◽

Cited By ~ 2

Author(s):

B. W. J. Miles ◽

C. R. Stokes ◽

S. S. R. Jamieson

Keyword(s):

Sea Ice ◽

East Antarctica ◽

High Temporal Resolution ◽

Ice Flow ◽

Outlet Glacier ◽

Ice Shelves ◽

Glacier Terminus ◽

Wilkes Land ◽

Speed Up

Abstract. The floating ice shelves and glacier tongues which fringe the Antarctic continent are important because they help buttress ice flow from the ice sheet interior. Dynamic feedbacks associated with glacier calving have the potential to reduce buttressing and subsequently increase ice flow into the ocean. However, there are few high temporal resolution studies on glacier calving, especially in East Antarctica. Here we use remote sensing to investigate monthly glacier terminus change across six marine-terminating outlet glaciers in Porpoise Bay (−76° S, 128° E), Wilkes Land (East Antarctica), between November 2002 and March 2012. This reveals a large simultaneous calving event in January 2007, resulting in a total of ~ 2900 km2 of ice being removed from glacier tongues. Our observations suggest that sea-ice must be removed from glacier termini for any form of calving to take place, and we link this major calving event to a rapid break-up of the multi-year sea-ice which usually occupies Porpoise Bay. Using sea-ice concentrations as a proxy for glacier calving, and by analysing available satellite imagery stretching back to 1963, we reconstruct the long-term calving activity of the largest glacier in Porpoise Bay: Holmes (West) Glacier. This reveals that its present-day velocity (~ 1450 m a−1) is approximately 50 % faster than between 1963 and 1973 (~ 900 m a−1). We also observed the start of a large calving event in Porpoise Bay in March 2016 that is consistent with our reconstructions of the periodicity of major calving events. These results highlight the importance of sea-ice in modulating outlet glacier calving and velocity in East Antarctica.

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ICE FLOW VELOCITY MAPPING IN EAST ANTARCTICA USING HISTORICAL IMAGES FROM 1960s TO 1980s: RECENT PROGRESS

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xliii-b3-2021-491-2021 ◽

2021 ◽

Vol XLIII-B3-2021 ◽

pp. 491-496

Author(s):

S. Luo ◽

Y. Cheng ◽

Z. Li ◽

Y. Wang ◽

K. Wang ◽

...

Keyword(s):

Mass Balance ◽

Flow Velocity ◽

East Antarctica ◽

Input Output ◽

Velocity Mapping ◽

Ice Flow ◽

Optical Images ◽

Elevation Changes ◽

Ice Velocity ◽

Surface Ice

Abstract. Recent research indicates that the estimated elevation changes and associated mass balance in East Antarctica are of some degree of uncertainty; a light accumulation has occurred in its vast inland regions, while mass loss in Wilkes Land appears significant. It is necessary to study the mass change trend in the context of a long period of the East Antarctic Ice Sheet (EAIS). The input-output method based on surface ice flow velocity and ice thickness is one of the most important ways to estimate the mass balance, which can provide longer-term knowledge of mass balance because of the availability of the early satellites in 1960s. In this study, we briefly describe the method of extracting ice velocity based on the historical optical images from 1960s to 1980s. Based on the draft ice velocity map of the EAIS using this method, we conduct a series of validation experiments, including comparisons with in-situ measurement, existing historical maps and rock outcrop dataset. Finally, we use the input-output method to estimate mass balance in some regions of EAIS using the generated velocity map.

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

Remote Sensing ◽

10.3390/rs12111809 ◽

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.

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COMPILING TECHNIQUES FOR EAST ANTARCTIC ICE VELOCITY MAPPING BASED ON HISTORICAL OPTICAL IMAGERY

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-3-2625-2018 ◽

2018 ◽

Vol XLII-3 ◽

pp. 2625-2628

Author(s):

X. Li ◽

R. Li ◽

G. Qiao ◽

Y. Cheng ◽

W. Ye ◽

...

Keyword(s):

Flow Velocity ◽

Image Matching ◽

Landsat Imagery ◽

East Antarctica ◽

Surface Velocity ◽

Velocity Mapping ◽

Large Space ◽

Ice Flow ◽

Ice Velocity ◽

Optical Imagery

Ice flow velocity over long time series in East Antarctica plays a vital role in estimating and predicting the mass balance of Antarctic Ice Sheet and its contribution to global sea level rise. However, there is no Antarctic ice velocity product with large space scale available showing the East Antarctic ice flow velocity pattern before the 1990s. We proposed three methods including parallax decomposition, grid-based NCC image matching, feature and gird-based image matching with constraints for estimation of surface velocity in East Antarctica based on ARGON KH-5 and LANDSAT imagery, showing the feasibility of using historical optical imagery to obtain Antarctic ice motion. Based on these previous studies, we presented a set of systematic method for developing ice surface velocity product for the entire East Antarctica from the 1960s to the 1980s in this paper.

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Simultaneous disintegration of outlet glaciers in Porpoise Bay (Wilkes Land), East Antarctica, driven by sea ice break-up

The Cryosphere ◽

10.5194/tc-11-427-2017 ◽

2017 ◽

Vol 11 (1) ◽

pp. 427-442 ◽

Cited By ~ 25

Author(s):

Bertie W. J. Miles ◽

Chris R. Stokes ◽

Stewart S. R. Jamieson

Keyword(s):

Sea Ice ◽

East Antarctica ◽

High Temporal Resolution ◽

Ice Flow ◽

Envisat Asar ◽

Glacier Terminus ◽

Wilkes Land ◽

Break Up ◽

Atmospheric Circulation Anomalies ◽

Landfast Sea Ice

Abstract. The floating ice shelves and glacier tongues which fringe the Antarctic continent are important because they help buttress ice flow from the ice sheet interior. Dynamic feedbacks associated with glacier calving have the potential to reduce buttressing and subsequently increase ice flow into the ocean. However, there are few high temporal resolution studies on glacier calving, especially in East Antarctica. Here we use ENVISAT ASAR wide swath mode imagery to investigate monthly glacier terminus change across six marine-terminating outlet glaciers in Porpoise Bay (76° S, 128° E), Wilkes Land (East Antarctica), between November 2002 and March 2012. This reveals a large near-simultaneous calving event in January 2007, resulting in a total of ∼  2900 km2 of ice being removed from glacier tongues. We also observe the start of a similar large near-simultaneous calving event in March 2016. Our observations suggest that both of these large calving events are driven by the break-up of the multi-year sea ice which usually occupies Porpoise Bay. However, these break-up events appear to have been driven by contrasting mechanisms. We link the 2007 sea ice break-up to atmospheric circulation anomalies in December 2005 weakening the multi-year sea ice through a combination of surface melt and a change in wind direction prior to its eventual break-up in January 2007. In contrast, the 2016 break-up event is linked to the terminus of Holmes (West) Glacier pushing the multi-year sea ice further into the open ocean, making the sea ice more vulnerable to break-up. In the context of predicted future warming and the sensitivity of sea ice to changes in climate, our results highlight the importance of interactions between landfast sea ice and glacier tongue stability in East Antarctica.

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