scholarly journals Decadal GPS-derived ice surface velocity along the transect from Zhongshan Station to and around Dome Argus, East Antarctica, 2005–16

2018 ◽  
Vol 59 (76pt1) ◽  
pp. 1-9 ◽  
Author(s):  
Yang Yuande ◽  
Ke Hao ◽  
Wang Zemin ◽  
Li Fei ◽  
Ding Minghu ◽  
...  
Keyword(s):  
High Resolution ◽  
Ground Truth ◽  
East Antarctica ◽  
Surface Velocity ◽  
Interferometric Synthetic Aperture Radar ◽  
Gps Measurements ◽  
Zhongshan Station ◽  
Ice Surface ◽  
Ice Velocity ◽  
Ice Sheet Dynamics

ABSTRACTUsing repeat GPS measurements during 2005–16, we calculated and updated two-dimensional high-resolution decadal ice surface velocity estimates along the traverse route from Zhongshan Station to and around Dome Argus, East Antarctica. Along the 71 sites of the transect, the magnitudes of ice velocity increased from near 0 in Dome Argus to 1, 10 and ~100 m a−1 at the sites DT416, DT333 and LT980, respectively. The comparison between GPS and interferometric synthetic aperture radar (InSAR) derived results agree well when the magnitude of the ice surface velocities is faster than 5 m a−1, and disagree for slower flow velocities. A scale value 1.15 and 0.12 can be applied to InSAR derived results over this region with ice surface velocity larger and <5 m a−1, respectively. We attributed the cause of the discrepancy to the insensitivity of InSAR to the magnitude of low ice surface velocities, thus confirming the importance of GPS fieldwork-based ground truth high-resolution ice velocity estimates to constrain ice-sheet dynamics.

scholarly journals Interferometric radar observations of Glaciares Europa and Penguin, Hielo Patagónico Sur, Chile

1999 ◽  
Vol 45 (150) ◽  
pp. 325-337 ◽  
Author(s):  
Richard R. Forster ◽  
Eric Rignot ◽  
Bryan L. Isacks ◽  
Kenneth C. Jezek
Keyword(s):  
Space Shuttle ◽  
Phase Coherence ◽  
Surface Velocity ◽  
Interferometric Synthetic Aperture Radar ◽  
Low Coherence ◽  
Ice Surface ◽  
Digital Elevation ◽  
Ice Velocity ◽  
Elevation Model ◽  
High Degree

AbstractRepeat-pass L-band interferometric synthetic aperture radar (InSAR) data for part of Hielo Patagónico Sur, Chile, were collected by the space-shuttle-based Spaceborne Imaging Radar C (SIR-C) over a 4 day span in October 1994. Three co-registered complex SAR images are used to generate phase-coherence maps, a digital elevation model (DEM) and an ice-velocity map. The phase-coherence maps indicate low coherence in the 5–15 km approaching the termini due to large displacements, ice deformation and melting. However, the coherence is high over nearly all of the remaining imaged icefield. Ice-velocity precision is greater than 2 cm d−1, while the DEM is good to about 25 m. A flow divide between two of the glaciers is mapped by locating a narrow band of near-zero ice velocity. Horizontal ice-surface velocity profiles calculated along flowlines show there is a high degree of spatial variability reaching a peak value of 5.5 m d−1 located 3.5 km from the terminus of Glaciar Europa. Longitudinal strain rates along the center lines calculated from these velocities at the locations of the initiation of crevassing are used to compute the tensile strength of ice (169–224 kPa).

scholarly journals Interferometric radar observations of Glaciares Europa and Penguin, Hielo Patagónico Sur, Chile

1999 ◽  
Vol 45 (150) ◽  
pp. 325-337 ◽  
Author(s):  
Richard R. Forster ◽  
Eric Rignot ◽  
Bryan L. Isacks ◽  
Kenneth C. Jezek
Keyword(s):  
Space Shuttle ◽  
Phase Coherence ◽  
Surface Velocity ◽  
Interferometric Synthetic Aperture Radar ◽  
Low Coherence ◽  
Ice Surface ◽  
Digital Elevation ◽  
Ice Velocity ◽  
Elevation Model ◽  
High Degree

AbstractRepeat-pass L-band interferometric synthetic aperture radar (InSAR) data for part of Hielo Patagónico Sur, Chile, were collected by the space-shuttle-based Spaceborne Imaging Radar C (SIR-C) over a 4 day span in October 1994. Three co-registered complex SAR images are used to generate phase-coherence maps, a digital elevation model (DEM) and an ice-velocity map. The phase-coherence maps indicate low coherence in the 5–15 km approaching the termini due to large displacements, ice deformation and melting. However, the coherence is high over nearly all of the remaining imaged icefield. Ice-velocity precision is greater than 2 cm d−1, while the DEM is good to about 25 m. A flow divide between two of the glaciers is mapped by locating a narrow band of near-zero ice velocity. Horizontal ice-surface velocity profiles calculated along flowlines show there is a high degree of spatial variability reaching a peak value of 5.5 m d−1located 3.5 km from the terminus of Glaciar Europa. Longitudinal strain rates along the center lines calculated from these velocities at the locations of the initiation of crevassing are used to compute the tensile strength of ice (169–224 kPa).

scholarly journals Ice velocity measurements of Langjökull, Iceland, from interferometric synthetic aperture radar (InSAR)

2009 ◽  
Vol 55 (193) ◽  
pp. 834-838 ◽  
Author(s):  
Steven Palmer ◽  
Andrew Shepherd ◽  
Helgi Björnsson ◽  
Finnur Pálsson
Keyword(s):  
Interferometric Synthetic Aperture Radar ◽  
Velocity Measurements ◽  
Gps Measurements ◽  
Ice Flow ◽  
Ice Cap ◽  
Gps Survey ◽  
Ice Surface ◽  
Ice Velocity ◽  
Elevation Model ◽  
Good Agreement

AbstractWe have computed the velocity of Langjökull ice cap (LIC), Iceland, using InSAR data acquired by the European Remote-sensing Satellite in 1994 and an ice-surface elevation model derived from a GPS survey conducted in 1997. The velocity map covers 68% of the 925 km2 of LIC. Eight principal outlet glaciers were identified, along which ice velocities increased from zero at the ice divide to a maximum of 75 m a−1. When the InSAR velocity dataset is compared with surface GPS measurements of ice flow determined in summer 2001, there is generally good agreement, suggesting interannual and seasonal stability for much of the ice cap during this period. However, non-zero ice velocities at the termini of four of the eight glaciers surveyed suggest that these glaciers were advancing in 1994. Comparison of our GPS and InSAR velocities suggests that Sudurjökull experienced elevated velocity in late February 1994, which, when other studies are considered, appears to be consistent with a glacier surge.

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 Recent high-resolution Antarctic ice velocity maps reveal increased mass loss in Wilkes Land, East Antarctica

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Qiang Shen ◽  
Hansheng Wang ◽  
C. K. Shum ◽  
Liming Jiang ◽  
Hou Tse Hsu ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Loss ◽  
East Antarctica ◽  
Wilkes Land ◽  
Ice Velocity

scholarly journals ERS SAR feature-tracking measurement of outlet glacier velocities on a regional scale in East Greenland

2003 ◽  
Vol 36 ◽  
pp. 129-134 ◽  
Author(s):  
Adrian Luckman ◽  
Tavi Murray ◽  
Hester Jiskoot ◽  
Hamish Pritchard ◽  
Tazio Strozzi
Keyword(s):  
Feature Tracking ◽  
Regional Scale ◽  
Surface Velocity ◽  
Ice Flow ◽  
Outlet Glacier ◽  
East Greenland ◽  
Ice Surface ◽  
Fast Ice ◽  
Regional Basis ◽  
Ice Velocity

AbstractFeature tracking, or patch intensity cross-correlation, is used to derive two-dimensional ice-surface velocity fields from 1day and 35 day repeat-pass European Remote-sensing Satellite (ERS) synthetic aperture radar (SAR) data covering a 500 km by 500 km area of central East Greenland. Over regions of fast ice flow, 35 day tracking yields only a slightly lower density of velocity measurements than 1day tracking, and both are broadly in agreement about the spatial pattern of ice velocity except at the glacier termini where tidal effects may dominate. This study suggests that SAR feature tracking may be used to routinely monitor ice-discharge velocities on a regional basis and thereby inform studies of regional mass balance.

scholarly journals Assessment of ICESat-2 ice surface elevations over the CHINARE route, East Antarctica, based on coordinated multi-sensor observations

2020 ◽  
Author(s):  
Rongxing Li ◽  
Hongwei Li ◽  
Tong Hao ◽  
Gang Qiao ◽  
Haotian Cui ◽  
...  
Keyword(s):  
East Antarctica ◽  
Continuous Assessment ◽  
Antarctic Region ◽  
Comprehensive Investigation ◽  
Zhongshan Station ◽  
Ice Surface ◽  
Operation Period ◽  
Antarctic Expedition ◽  
Gnss Receivers ◽  
Antarctic Research

Abstract. This paper presents the results of the assessment of ICESat-2 ice surface elevations along the CHINARE (CHINese Antarctic Research Expedition) route in East Antarctica. The validation campaign was designed and implemented in cooperation with the 36th CHINARE Antarctic expedition from December 2019 to February 2020. The assessment of the ICESat-2 ATL03 and ATL06 data was performed based on coordinated multi-sensor observations using two roof-mounted kinematic GNSS receivers, two line arrays of corner cube retroreflectors (CCRs), two sets of retroreflective target sheets (RTSs), and two unmanned aerial vehicles (UAVs) with cameras. This systematic validation of the ICESat-2 data covered a variety of Antarctic ice surface conditions along the 520 km traverse from the coastal Zhongshan Station to the inland Taishan Station. This comprehensive investigation is complementary to the 750 km traverse validation of flat inland Antarctica containing a 300 km latitude traverse of 88° S by the mission team in a previous study. Overall, the validation results show that the elevation of the ATL06 ice surface points is accurate to 1.1 cm with a precision of 9.7 cm along the 520 km CHINARE route. The elevation of the ATL03 photons has an offset of 2.4 cm from a GNSS-surveyed CCR, and is accurate to 2.5 cm with a precision of 2.7 cm as estimated by using RTSs. The validation results demonstrate that the estimated ICESat-2 elevations are accurate to 1.1–2.5 cm in this East Antarctic region, which is important for overcoming the uncertainties in the estimation of mass balance in East Antarctica. The developed validation methodology and sensor system can be improved for continuous assessment of ICESat-2 data, especially during the later operation period.

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

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.

Sign in / Sign up

Export Citation Format

Share Document