Geomorphometric modeling and mapping of Antarctic oases

Geomorphometric modeling is widely used in geosciences. However, geomorphometric modeling and mapping of Antarctic oases has not been performed so far. This article presents the first results of our work on geomorphometric modeling and mapping of several Antarctic oases including the Larsemann Hills, Thala Hills, Schirmacher oasis, and Fildes Peninsula. As input data, we used fragments of the Reference Elevation Model of Antarctica. For each territory, we derived digital models of the following 17 morphometric variables from the extracted and edited digital elevation models: slope, aspect, horizontal curvature, vertical curvature, mean curvature, Gaussian curvature, minimal curvature, maximal curvature, unsphericity curvature, difference curvature, vertical excess curvature, horizontal excess curvature, ring curvature, accumulation curvature, catchment area, topographic index, and stream power index. Derived geomorphometric maps can be useful for structural geological and process-oriented hydrological studies. The ultimate goal of the ongoing work is to create a digital large-scale geomorphometric atlas of Antarctic oases and other ice-free Antarctic territories.Comment: 84 pages, 72 figure

Late Quaternary relative sea level change in the South Shetland Islands, Antarctica

Models have been inconsistent in their prediction of ice sheet volumes and extent over the Antarctic Peninsula and sub-Antarctic islands during the Last Glacial Maximum (LGM), and their contribution to sea level rise during subsequent deglaciation remains uncertain. The use of precise relative sea level (RSL) data offers great potential for inferring regional ice sheet histories, as well as helping to validate numerical models predicting future ice sheet evolution and RSL change. This thesis aims to elucidate the RSL history of the South Shetland Islands (SSIs), a sub-Antarctic archipelago peripheral to the northern Antarctic Peninsula ice sheet, by integrating evidence from isolation basins with geomorphological evidence from raised beaches. This will extend the only previously reported RSL curve from the area (Bentley et al., 2005a), which reveals a complex but poorly chronologically constrained RSL history. In addition, this work also aims to improve the understanding of the long-term tectonic influence on RSL change. Sediment cores were taken from five lakes on Fildes Peninsula, King George Island (eastern SSIs) at a range of altitudes above present sea level. Diatom, stable isotope (δ13C) and physical analyses of sediments revealed clear marine-lacustrine transitions in lakes below 16 m above mean sea level (amsl), with no marine signal above this altitude. Together with radiocarbon dates from raised beaches, a RSL curve was produced for the last 9500 14C yr BP. This curve shows a mid-Holocene RSL highstand at 15.5 m amsl between ca. 6150 and 6700 14C yr BP, preceded by a period of extremely rapid RSL rise and followed by more gradual RSL fall as a consequence of isostatic uplift in response to regional deglaciation. In addition, regional GPS surveys of raised beaches were conducted to assess the spatial pattern of glacio-isostatic rebound following deglaciation. The centre of uplift was found to closely coincide with the centre of the LGM ice sheet reconstructed by John and Sugden (1971). Beaches were modelled using polynomial trend surface analysis to constrain the spatial variability of isostatic uplift across the SSIs, which has enabled the regional extrapolation of the RSL curve across the archipelago. Finally, two independent approaches were taken to constrain the long-term tectonic uplift rate of the SSIs as 0.22-0.48 m/ka. Tectonic uplift contributes between 1.4 and 2.9 m to the reconstructed RSL highstand

Progress and prospects in Chinese Antarctic surveying, mapping and remote sensing studies

Antarctic surveying, mapping and remote sensing is one of the important aspects of the Chinese Antarctic geoscience research program that stretch back over 25 years, since the first Chinese National Antarctic Research Expedition (CHINARE) in 1984. During the 1980’s, the geodetic datum, height system and absolute gravity datum were established at the Great Wall and Zhongshan Stations. Significant contributions have been made by the construction of the Chinese Great Wall, Zhongshan and Kunlun Stations in Antarctica. Geodetic control and gravity networks were established in the King George Islands, Grove Mountains and Dome Argus. An area of more than 200 000 km2 has been mapped using satellite image data, aerial photogrammetry and in situ data. Permanent GPS stations and tide gauges have been established at both the Great Wall and Zhongshan Stations. Studies involving plate motion, precise satellite orbit determination, the gravity field, sea level change, and various GPS applications for atmospheric studies have been carried out. Based on remote sensing techniques, studies have been undertaken on ice sheet and glacier movements, the distributions of blue ice and ice crevasses, and ice mass balance. Polar digital and visual mapping techniques have been introduced, and a polar survey space database has been built. The Chinese polar scientific expedition management information system and Chinese PANDA plan display platform were developed, which provides technical support for Chinese polar management. Finally, this paper examines prospects for future Chinese Antarctic surveying, mapping and remote sensing

Progress in Chinese Antarctic geodetic remote sensing

This paper summarizes the progress of the Chinese Antarctic expedition in geodetic remote sensing. It describes the systems for continuous satellite navigation and positioning, and the tide gauges that have been established at the Zhongshan and Great Wall stations in Antarctica. Advances in the investigation of plate motion, the gravity field, and sea level change as well as the application of GPS in atmospheric studies are reported. Details of the movements of ice sheets and glaciers, distributions of blue ice and ice crevasses, and mass balance studies based on remote sensing techniques are presented. The use of field, satellite, and photogrammetric data to produce topographic maps is described. Finally, the prospects for further Antarctic surveying and mapping are discussed. In the near future, we will establish a high-precision geodetic datum in the Chinese Antarctic expedition areas, monitor changes of Antarctic snow and ice, and develop a platform for sharing Antarctic resource and environment information

Recent Deceleration of the Ice Elevation Change of Ecology Glacier (King George Island, Antarctica)

Glacier change studies in the Antarctic Peninsula region, despite their importance for global sea level rise, are commonly restricted to the investigation of frontal position changes. Here we present a long term (37 years; 1979–2016) study of ice elevation changes of the Ecology Glacier, King George Island ( 62 ∘ 11 ′ S, 58 ∘ 29 ′ W). The glacier covers an area of 5.21 km 2 and is located close to the H. Arctowski Polish Antarctic Station, and therefore has been an object of various multidisciplinary studies with subject ranging from glaciology, meteorology to glacial microbiology. Hence, it is of great interest to assess its current state and put it in a broader context of recent glacial change. In order to achieve that goal, we conducted an analysis of archival cartographic material and combined it with field measurements of proglacial lagoon hydrography and state-of-art geodetic surveying of the glacier surface with terrestrial laser scanning and satellite imagery. Overall mass loss was largest in the beginning of 2000s, and the rate of elevation change substantially decreased between 2012–2016, with little ice front retreat and no significant surface lowering. Ice elevation change rate for the common ablation area over all analyzed periods (1979–2001–2012–2016) has decreased from −1.7 ± 0.4 m/year in 1979–2001 and −1.5 ± 0.5 m/year in 2001–2012 to −0.5 ± 0.6 m/year in 2012–2016. This reduction of ice mass loss is likely related to decreasing summer temperatures in this region of the Antarctic Peninsula