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

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.

scholarly journals ICE FLOW VELOCITY MAPPING OF EAST ANTARCTICA FROM 1963 TO 1989

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 1735-1739
Author(s):  
Y. Cheng ◽  
X. Li ◽  
G. Qiao ◽  
W. Ye ◽  
Y. Huang ◽  
...  
Keyword(s):  
Flow Velocity ◽  
East Antarctica ◽  
Surface Velocity ◽  
Velocity Mapping ◽  
Landsat Images ◽  
Ice Flow ◽  
Continental Scale ◽  
Optical Images ◽  
Long Time ◽  
Surface Ice

<p><strong>Abstract.</strong> Long-time serial observation of surface ice flow velocity in Antarctic is a crucial component in estimating the mass balance of Antarctic ice sheet. However, there is a lack of historical continental scale velocity maps of Antarctica before the 1990s. Historical optical images such as ARGON and Landsat images before 1990s are difficult to be used for ice flow velocity mapping, due to the fact that they are mostly not strictly geo-processed (e.g., ortho-rectified) and the image quality is lower than those of recent sensors. This paper presents a systematic framework for developing a surface velocity map of East Antarctica from 1963 to 1989 based on historical ARGON and Landsat images, followed by analysis of spatial-temporal changes of the ice flow velocity in some major glaciers, as well as the dynamic changes. The preliminary comparison with existing products suggests that the glaciers in Wilkes Land experienced an increasing trend with obvious fluctuations during the past &amp;sim;50 years, while the glaciers near Transantarctic Mountains tended to be stable or slightly fluctuating to a certain degree.</p>

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.

Corner Reflectors for Validation of Ice Flow Velocity Derived from SAR Images along the CHINARE-Route in Antarctica

2020 ◽  
Author(s):  
Gang Qiao ◽  
Rongxing Li ◽  
Tong Hao ◽  
Xiaohua Tong ◽  
Yanjun Li ◽  
...  
Keyword(s):  
Mass Balance ◽  
Flow Velocity ◽  
Incident Angle ◽  
Surface Shape ◽  
Sar Images ◽  
Ice Flow ◽  
Ground Truth Data ◽  
Radar Images ◽  
Ice Velocity

&lt;p&gt;Ice flow velocity is an important parameter for evaluating the stability of Antarctic ice shelves and analyzing the mass balance of the ice sheet. Large scale ice flow maps can be produced from satellite images with ground control and validation. Among various ground targets, corner reflectors show distinct intensity characteristics on SAR images due to its highly reflective surface shape and have been used for calibration and validation. This paper focuses on design and implementation of a set of corner reflectors to obtain the first-hand data of in-situ ice flow velocity for SAR image based ice velocity maps. The results should further help evaluate mass balance changes in East Antarctica using the input-output method.&lt;/p&gt;&lt;p&gt;Generally, the remote sensing method uses airborne or satellite optical and radar images from multiple periods to map ice flow velocity fields. The ground truth data are often sparse due to the harsh environment in the polar region. The annual Chinese Antarctic Research Expedition (CHINARE) makes it possible to obtain period field data of ice velocity within its campaign regions. The ~1200 km CHINARE-Route runs from Zhongshan Station to Kunlun Station along which the ice flow velocity varies from a few meters per year to 100s meters per year. 5 corner reflectors have been designed and installed along the 31st CHINARE-Route in 2015 and the 35th CHINARE-Route in 2019 (M1, M2 and M3 in the 31st CHINARE, A1and A2 in the 35th CHINARE). The ice flow velocities at the installation locations are of different orders of magnitude, about 44 m per year at the locations of M1 and A1, 93 m per year at M2 and M3 and 73 m per year at A2. The satellite orbit inclination, incident angle and the installation location were used to calculate the azimuth and elevation angles of the corner reflectors for installation. At all reflector locations GPS positions were collected at the time of installation. After that, the second time GPS coordinates of M3 in the 34th CHINARE in 2018, the third time GPS coordinates of M3, the second time GPS coordinates of A1 and A2 in the 36th CHINARE at the end of 2019 were measured respectively. TerraSAR-X was used to image the reflectors.&lt;/p&gt;&lt;p&gt;The results show that the mean in-situ ice flow velocity of M3 is 96.83 m per year between Feb. 2015 and Dec. 2019, with 97.51 m per year between Feb. 2015 and Jan. 2018 and 95.81m per year between Jan. 2018 and Dec. 2019. The in-situ ice flow velocity is 54.9 m per year at A1 between Jan. 2019 and Dec. 2019 and 86.92 m per year at A2 between Feb. 2019 and Dec. 2019. More TerraSAR-X and COSMO-SkyMed data will be used to extract the ice velocity corresponding to GPS measurements. The detailed information will be presented at the meeting.&lt;/p&gt;

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

2014 ◽  
Vol 26 (6) ◽  
pp. 636-645 ◽  
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.

scholarly journals Radar-detected englacial stratigraphy in the Pensacola Mountains, Antarctica: implications for recent changes in ice flow and accumulation

2013 ◽  
Vol 54 (63) ◽  
pp. 91-100 ◽  
Author(s):  
Seth Campbell ◽  
Greg Balco ◽  
Claire Todd ◽  
Howard Conway ◽  
Kathleen Huybers ◽  
...  
Keyword(s):  
Mass Balance ◽  
Surface Elevation ◽  
Ice Flow ◽  
Ice Surface ◽  
Valley Glacier ◽  
Glacier Ice ◽  
Elevation Changes ◽  
Ice Sheet Dynamics ◽  
Surface Ice ◽  
Ground Penetrating

AbstractWe used measurements of radar-detected stratigraphy, surface ice-flow velocities and accumulation rates to investigate relationships between local valley-glacier and regional ice-sheet dynamics in and around the Schmidt Hills, Pensacola Mountains, Antarctica. Ground-penetrating radar profiles were collected perpendicular to the long axis of the Schmidt Hills and the margin of Foundation Ice Stream (FIS). Within the valley confines, the glacier consists of blue ice, and profiles show internal stratigraphy dipping steeply toward the nunataks and truncated at the present-day ablation surface. Below the valley confines, the blue ice is overlain by firn. Data show that upward-progressing overlap of actively accumulating firn onto valley-glacier ice is slightly less than ice flow out of the valleys over the past ∼1200 years. The apparent slightly negative mass balance (-0.25 cm a-1) suggests that ice-margin elevations in the Schmidt Hills may have lowered over this time period, even without a change in the surface elevation of FIS. Results suggest that (1) mass-balance gradients between local valley glaciers and regional ice sheets should be considered when using local information to estimate regional ice surface elevation changes; and (2) interpretation of shallow ice structures imaged with radar can provide information about local ice elevation changes and stability.

scholarly journals ICE VELOCITY MEASUREMENT IN EAST ANTARCTICA FROM 1960s TO 1980s BASED ON ARGON AND LANDSAT IMAGERY

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 1535-1539 ◽  
Author(s):  
R. Li ◽  
X. Ma ◽  
Y. Cheng ◽  
W. Ye ◽  
S. Guo ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Feature Matching ◽  
Geometric Model ◽  
East Antarctica ◽  
Surface Velocity ◽  
Time Interval ◽  
Stereo Pair ◽  
Landsat Images ◽  
Ice Flow ◽  
Ice Velocity

Ice flow velocity is a vital parameter for estimating the ice mass balance of glaciers in Antarctica. Especially long time serial observation of the surface velocity is of great significance to assessing the relationship between Antarctic ice materials and global climate change. However, the existing research on Antarctic ice velocity based on remote sensing data since 1970s due to the harsh climate in Antarctica. This paper presents an ice flow velocity estimating method includes image pre-processing, geometric model reconstruction, image ortho-rectification and feature matching by using ARGON images token in 1963 and Landsat images collected form 1973 to 1989.Considering the temporal-spatial distributions of ARGON images and Landsat images in Antarctica, two different methods respectively based on ortho-photos pair and Non-Ortho photos are adopted in this paper. More specifically, when there exist two stereo pairs taken in different time in the glacier region, after being ortho-rectified, the stereo pairs can be used to calculate ice flow velocity based on feature matching method. Otherwise, a parallax decomposition method that separates the effect of the terrain relief from the ice flow motion is applied when there only exists one stereo pair with a certain time interval. With this method, glacier surface velocity is available in the glacier region lacked enough stereo pairs. The methods mentioned above for estimating ice flow velocity are applied in Totten, Amery and Fimbul, etc. in eastern Antarctica. Furthermore, a 1960-80s ice flow speed map in the main glaciers of East Antarctica is produced for the first time.

scholarly journals Ice flow velocities over Vostok Subglacial Lake, East Antarctica, determined by 10 years of GNSS observations

2013 ◽  
Vol 59 (214) ◽  
pp. 315-326 ◽  
Author(s):  
A. Richter ◽  
D.V. Fedorov ◽  
M. Fritsche ◽  
S.V. Popov ◽  
V.Ya. Lipenkov ◽  
...  
Keyword(s):  
Flow Velocity ◽  
East Antarctica ◽  
Global Navigation Satellite Systems ◽  
Steady Increase ◽  
Lake Area ◽  
Ice Flow ◽  
Satellite Systems ◽  
Subglacial Lake ◽  
Gnss Observations ◽  
Flow Velocities

AbstractRepeated Global Navigation Satellite Systems (GNSS) observations were carried out at 50 surface markers in the Vostok Subglacial Lake (East Antarctica) region between 2001 and 2011. The horizontal ice flow velocity vectors were derived with accuracies of 1 cm a−1 and 0.5°, representing the first reliable information on ice flow kinematics in the northern part of the lake. Within the lake area, ice flow velocities do not exceed 2 m a−1. The ice flow azimuth is southeast in the southern part of the lake and turns gradually to east-northeast in the northern part. In the northern part, as the ice flow enters the lake at the western shore, the velocity decreases towards the central lake axis, then increases slightly past the central axis. In the southern part, a continued acceleration is observed from the central lake axis across the downstream grounding line. Based on the observed flow velocity vectors and ice thickness data, mean surface accumulation rates are inferred for four surface segments between Ridge B and Vostok Subglacial Lake and show a steady increase towards the north.

scholarly journals Measured Velocities of Interior East Antarctica and the State of Mass Balance Within the I.A.G.P. Area

1979 ◽  
Vol 24 (90) ◽  
pp. 77-87 ◽  
Author(s):  
N. W. Young
Keyword(s):  
Mass Balance ◽  
Total Mass ◽  
East Antarctica ◽  
Velocity Measurements ◽  
Drainage Basins ◽  
Mass Budget ◽  
Large Sector ◽  
Ice Velocity ◽  
True Mass ◽  
Made In

AbstractRecent measurements of accumulation and ice velocity made in the interior of East Antarctica indicate that a large sector between longitudes 80° E. and 135° E. and north of latitude 80° S. has close to a zero net mass budget. This sector is within the study area for the International Antarctic Glaciological Project (I.A.G.P.) and covers a major portion of the area indicated for projects of special emphasis. Velocity measurements were made at a number of points on a traverse route from Mirny (lat. 66° 33′ S., long. 93°00′ E.) on the coast Dome “C” (lat. 74° 40′ S., long. 124° 00′ E.), in the interior. Accumulation measurements were made along this and other traverse routes, extending as far as Vostok (lat. 78° 28′ S., long. 106° 50′ E.), by a number of methods. These included stake, stratigraphic, isotopic, and totalβ-decay observations. The better accumulation data have allowed a review of the total mass input to be made. The true mass budget has been estimated by comparing velocities, calculated assuming a zero net mass budget with measured velocities along the traverse routes and on a number of the outlet glaciers. For this purpose the area was divided into a number of drainage basins according to outlet at the coast. The area of about 106km2and 150 Gt a−1flux input is drained primarily by three glacier systems of which the Totten accounts for 40% of the flux from 55% of the area; the Vanderford 20% from 15%; and the Scott/Denman 20% from 20%.

scholarly journals Wave Ogives

1986 ◽  
Vol 32 (112) ◽  
pp. 325-334 ◽  
Author(s):  
E.D. Waddington
Keyword(s):  
Mass Balance ◽  
Method Of Characteristics ◽  
Wave Pattern ◽  
Wave Excitation ◽  
Ice Flow ◽  
Forcing Function ◽  
Excitation Potential ◽  
Ice Velocity ◽  
Balance Functions ◽  
Velocity Channel

AbstractWave ogives arise in a solution of the continuity equation by the method of characteristics. Steady ice flow is assumed. Ice velocity, channel width, and mass-balance functions combine to form a wave-excitation potential that yields the forcing function for wave ogives. This linear-systems formulation extends the ogive theory of Nye. Convolution of the temporal cumulative mass balance and spatial forcing functions gives the total wave pattern below an ice fall. Many ice falls do not generate ogives because the wave amplitude is modulated by a factor related to ice-fall length. The wave ogives at Austerdalsbreen, Norway, are due almost entirely to ice acceleration at the top of the ice-fall, i.e. the same zone that King and Lewis showed was responsible for forming Forbes bands.

scholarly journals A new approach to estimate ice dynamic rates using satellite observations in East Antarctica

2016 ◽  
Author(s):  
Bianca Kallenberg ◽  
Paul Tregoning ◽  
Janosch F. Hoffmann ◽  
Rhys Hawkins ◽  
Anthony Purcell ◽  
...  
Keyword(s):  
Mass Balance ◽  
Satellite Altimetry ◽  
Ice Sheet ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Antarctic Ice Sheet ◽  
Surface Mass ◽  
Elevation Changes ◽  
Ice Sheet Mass Balance ◽  
The Antarctic

Abstract. Mass balance changes of the Antarctic ice sheet are of significant interest due to its sensitivity to climatic changes and its contribution to changes in global sea level. While regional climate models successfully estimate mass input due to snowfall, it remains difficult to estimate the amount of mass loss due to ice dynamic processes. It's often been assumed that changes in ice dynamic rates only need to be considered when assessing long term ice sheet mass balance; however, two decades of satellite altimetry observations reveal that the Antarctic ice sheet changes unexpectedly and much more dynamically than previously expected. Despite available estimates on ice dynamic rates obtained from radar altimetry, information about changes in ice dynamic rates are still limited, especially in East Antarctica. Without understanding ice dynamic rates it is not possible to properly assess changes in ice sheet mass balance, surface elevation or to develop ice sheet models. In this study we investigate the possibility of estimating ice dynamic rates by removing modelled rates of surface mass balance, firn compaction and bedrock uplift from satellite altimetry and gravity observations. With similar rates of ice discharge acquired from two different satellite missions we show that it is possible to obtain an approximation of ice dynamic rates by combining altimetry and gravity observations. Thus, surface elevation changes due to surface mass balance, firn compaction and ice dynamic rates can be modelled and correlate with observed elevation changes from satellite altimetry.

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