lambert glacier
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2022 ◽  
Vol 14 (2) ◽  
pp. 391
Author(s):  
Derui Xu ◽  
Xueyuan Tang ◽  
Shuhu Yang ◽  
Yun Zhang ◽  
Lijuan Wang ◽  
...  

Due to rapid global warming, the relationship between the mass loss of the Antarctic ice sheet and rising sea levels are attracting widespread attention. The Lambert–Amery glacial system is the largest drainage system in East Antarctica, and its mass balance has an important influence on the stability of the Antarctic ice sheet. In this paper, the recent ice flux in the Lambert Glacier of the Lambert–Amery system was systematically analyzed based on recently updated remote sensing data. According to Landsat-8 ice velocity data from 2018 to April 2019 and the updated Bedmachine v2 ice thickness dataset in 2021, the contribution of ice flux approximately 140 km downstream from Dome A in the Lambert Glacier area to downstream from the glacier is 8.5 ± 1.9, and the ice flux in the middle of the convergence region is 18.9 ± 2.9. The ice mass input into the Amery ice shelf through the grounding line of the whole glacier is 19.9 ± 1.3. The ice flux output from the mainstream area of the grounding line is 19.3 ± 1.0. Using the annual SMB data of the regional atmospheric climate model (RACMO v2.3) as the quality input, the mass balance of the upper, middle, and lower reaches of the Lambert Glacier was analyzed. The results show that recent positive accumulation appears in the middle region of the glacier (about 74–78°S, 67–85°E) and the net accumulation of the whole glacier is 2.4 ± 3.5. Although the mass balance of the Lambert Glacier continues to show a positive accumulation, and the positive value in the region is decreasing compared with values obtained in early 2000.


2021 ◽  
Author(s):  
Nadezda Sushchevskaya ◽  
German Leitchenkov ◽  
Boris Belyatsky

<p>The Mesozoic Karoo-Maud and Kerguelen plumes had a significant influence on Gondwana and the oceanic lithosphere. Jurassic magmatism, formed under the influence of a huge Karoo plume at 184–178 Ma ago, covered large areas of the Dronning Maud Land in East Antarctica. Later, 130 – 0 m.y. ago, under the influence of the Kerguelen plume, magmatism formed in the area of the Lambert glacier, and the Gaussberg volcano (Quaternary time) appeared, located on the coast opposite the Kerguelen archipelago. We assume that the Karoo mantle plume initiated the formation of a “mega-apophyses” from the main plume manifestation area within the Karoo province in the southeastern African continet (ca. 2000 km in diameter). These mega-apophyses are represented by the Ferrar Igneous Province (ca. 3000 km long area of intrusive activity along the Transantarctic Mountains) and a supposed igneous province (ca. 1500 km long) covering the East Antarctic coast between the Lazarev and Cosmonauts Seas. Based on petrological and geochemical studies, the characteristic features of magmas of the Karoo, Dronning Maud Land, and Ferrar igneous provinces have been determined, which indicate that for all magmas associated with Karoo and Kerguelen plumes, the main source of melt enrichment is a mantle source with characteristics of the EM-II component (most typically for magmas of the Ferrar Province). It reflects the properties of an enriched, fluid-rich, ancient continental mantle, metasomatized at the early stages of the tectonic development of the region and involved in the melting process. A rarer admixture of the ancient lithospheric component (EM-I, with <sup>206</sup>Pb/<sup>204</sup>Pb = 16.5 and <sup>143</sup>Nd/<sup>144</sup>Nd = 0.5122) was revealed in both plumes. The existence of mantle plumes in the Southern Hemisphere and their long-term development had a significant impact on the structure and evolution of the East Antarctica.</p>


2021 ◽  
Vol 252 ◽  
pp. 106738
Author(s):  
Li Wu ◽  
David J. Wilson ◽  
Rujian Wang ◽  
Sandra Passchier ◽  
Wout Krijgsman ◽  
...  

Author(s):  
X. Tang ◽  
K. Luo ◽  
J. Guo

Abstract. The internal layers of ice sheets from ice-penetrating radar (IPR) investigation preserve critical information about the englacial conditions and ice-flow field. This paper presents a new detailed analysis of the spatial distribution characteristics of internal layers and subglacial topography of East Antarctic ice sheet (EAIS) from Zhongshan station to Dome A. Taking the internal layering continuity index (ILCI) and basal roughness as indicators, it provides an opportunity to evaluate the past internal environment and dynamics of ice sheet. The radar data of 1244 km along a traverse between Zhongshan Station and Dome A of EAIS was collected during the 29th Chinese National Antarctic Research Expedition (CHINARE 29, 2012/2013). Except for the upstream of Lambert Glacier, the patterns of the folds in the internal layers are basically similar to the bed topography. The relatively flat basal topography and the decrease of ILCI with the deepening of the depth provide evidence for identifying previous rapid ice flow areas that the satellite cannot obtain, especially in the upstream of Lambert Glacier. Well continuous internal layers of Dome A almost extend to the bed, with high ILCI and high roughness characteristics. There are three kinds of basal roughness patterns in the whole traverse. The characteristics of the internal layer and basal topography of the traverse between Zhongshan Station and Dome A provide new information for understanding the ancient ice-flow activity and the historical evolution of EAIS.


2020 ◽  
Vol 12 (7) ◽  
pp. 1079
Author(s):  
Kun Luo ◽  
Sixin Liu ◽  
Jingxue Guo ◽  
Tiantian Wang ◽  
Lin Li ◽  
...  

The internal layers of ice sheets from ice-penetrating radar (IPR) investigation preserve critical information about the ice-flow field and englacial conditions. This paper presents a new detailed analysis of spatial distribution characteristics of internal layers and subglacial topography of the East Antarctic ice sheet (EAIS) from Zhongshan Station to Dome A. The radar data of 1244 km along a traverse between Zhongshan Station and Dome A of EAIS were collected during the 29th Chinese National Antarctic Research Expedition (CHINARE 29, 2012/2013). In this study, the Internal Layering Continuity Index (ILCI) and basal roughness were taken as indicators to provide an opportunity to evaluate the past internal environment and dynamics of the ice sheet. Except for the upstream of Lambert Glacier, the fold patterns of internal layers are basically similar to that of the bed topography. The relatively flat basal topography and the decrease of ILCI with increasing depth provide evidence for identifying previous rapid ice flow areas that are unavailable to satellites, especially in the upstream of Lambert Glacier. Continuous internal layers of Dome A, recording the spatial change of past ice accumulation and ice-flow history over 160 ka, almost extend to the bed, with high ILCI and high basal roughness of the corresponding bed topography. There are three kinds of basal roughness patterns along the traverse, that is, “low ξt low η”, “low ξt high η”, and “high ξt high η”, where ξt represents the amplitude of the undulations, and quantifies the vertical variation of the bedrock, and η measures the frequency variation of fluctuations and the horizontal irregularity of the profile. The characteristics of internal layers and basal topography of the traverse between Zhongshan Station and Dome A provide new information for understanding the ancient ice-flow activity and the historical evolution of EAIS.


2020 ◽  
Vol 61 (81) ◽  
pp. 14-24 ◽  
Author(s):  
Sergey Popov

AbstractRussian (former Soviet) systematic studies of Antarctica by radio-echo sounding (RES) and ground-penetrating radar technique (GPR) were commenced in 1964. Since that time airborne RES surveys have covered about 5.5 × 106 km2 of the icy continent discovering remarkable geographic objects such as Subglacial Gamburtsev Mountains, and allowed studies of Filchner-Ronne Ice Shelf, Amery Ice Shelf and Lambert Glacier. Ground-based investigations during the 1990s and 2000s revealed the structure of the Lake Vostok area and surveyed along the Mirny to Vostok and Progress to Vostok traverse routes. GPR studies during the 2010s were to select the site for a new snow-runway at Mirny Station, with the resumption of the aviation after a 25 year hiatus.


Author(s):  
G. Hai ◽  
H. Xie ◽  
J. Chen ◽  
L. Chen ◽  
R. Li ◽  
...  

DEM Extraction from ASTER stereo pairs and three-dimensional registration by reference to ICESat laser altimetry data are carried out in upstream area of Lambert Glacier, East Antarctica. Since the study area is located in inland of East Antarctica where few textures exist, registration between DEM and ICESat data is performed. Firstly, the ASTER DEM generation is based on rational function model (RFM) and the procedure includes: a) rational polynomial coefficient (RPC) computation from ASTER metadata, b) L1A image product de-noise and destriping, c) local histogram equalization and matching, d) artificial collection of tie points and bundle adjustment, and e) coarse-to-fine hierarchical matching of five levels and grid matching. The matching results are filtered semi-automatically. Hereafter, DEM is interpolated using spline method with ground points converted from matching points. Secondly, the generated ASTER DEM is registered to ICESat data in three-dimensional space after Least-squares rigid transformation using singular value decomposition (SVD). The process is stated as: a) correspondence selection of terrain feature points from ICESat and DEM profiles, b) rigid transformation of generated ASTER DEM using selected feature correspondences based on least squares technique. The registration shows a good result that the elevation difference between DEM and ICESat data is low with a mean value less than 2 meters and the standard deviation around 7 meters. This DEM is generated and specially registered in Antarctic typical region without obvious ground rock control points and serves as true terrain input for further radar altimetry simulation.


2016 ◽  
Vol 62 (235) ◽  
pp. 888-904 ◽  
Author(s):  
HUAN XIE ◽  
RONGXING LI ◽  
XIAOHUA TONG ◽  
XIAOLEI JU ◽  
JUN LIU ◽  
...  

ABSTRACTWe present results of a regional comparative study of surface mass changes from 2004 to 2008 based on Gravity Recovery and Climate Experiment (GRACE), The Ice, Cloud and Land Elevation Satellite (ICESat) and CHINARE observations over the Lambert Glacier/Amery Ice Shelf system (LAS). Estimation of the ICESat mass change rates benefitted from the density measurements along the CHINARE traverse and a spatial density adjustment method for reducing the effect of spatial density variations. In the high-elevation inland region, a positive trend was estimated from both ICESat and GRACE data, which is in line with the CHINARE accumulation measurements. In the coastal region, there were areas with high level accumulations in both ICESat and GRACE trend maps. In many high flow-speed glacier areas, negative mass change rates may be caused by dynamic ice flow discharges that have surpassed the snow accumulation. Overall, the mass change rate estimate in the LAS of 2004–2008 from the GRACE, ICESat and CHINARE data is 5.41 ± 4.59 Gt a−1, indicating a balanced to slightly positive mass trend. Along with other published results, this suggests that a longer-term positive mass trend in the LAS may have slowed in recent years.


2014 ◽  
Vol 8 (3) ◽  
pp. 1057-1068 ◽  
Author(s):  
Y. Gong ◽  
S. L. Cornford ◽  
A. J. Payne

Abstract. The interaction between the climate system and the large polar ice sheet regions is a key process in global environmental change. We carried out dynamic ice simulations of one of the largest drainage systems in East Antarctica: the Lambert Glacier–Amery Ice Shelf system, with an adaptive mesh ice sheet model. The ice sheet model is driven by surface accumulation and basal melt rates computed by the FESOM (Finite-Element Sea-Ice Ocean Model) ocean model and the RACMO2 (Regional Atmospheric Climate Model) and LMDZ4 (Laboratoire de Météorologie Dynamique Zoom) atmosphere models. The change of ice thickness and velocity in the ice shelf is mainly influenced by the basal melt distribution, but, although the ice shelf thins in most of the simulations, there is little grounding line retreat. We find that the Lambert Glacier grounding line can retreat as much as 40 km if there is sufficient thinning of the ice shelf south of Clemence Massif, but the ocean model does not provide sufficiently high melt rates in that region. Overall, the increased accumulation computed by the atmosphere models outweighs ice stream acceleration so that the net contribution to sea level rise is negative.


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