198 results found
Malard LA, Sabacka M, Magiopoulos I, et al., 2019, Spatial Variability of Antarctic Surface Snow Bacterial Communities, FRONTIERS IN MICROBIOLOGY, Vol: 10, ISSN: 1664-302X
Cooper MA, Jordan TM, Siegert MJ, et al., 2019, Surface Expression of Basal and Englacial Features, Properties, and Processes of the Greenland Ice Sheet, GEOPHYSICAL RESEARCH LETTERS, Vol: 46, Pages: 783-793, ISSN: 0094-8276
Wang B, Sun B, Wang J, et al., 2019, Removal of 'strip noise' in radio-echo sounding data using combined wavelet and 2-D DFT filtering, Annals of Glaciology, ISSN: 0260-3055
© 2019 The Author(s). Radio-echo sounding (RES) can be used to understand ice-sheet processes, englacial flow structures and bed properties, making it one of the most popular tools in glaciological exploration. However, RES data are often subject to 'strip noise', caused by internal instrument noise and interference, and/or external environmental interference, which can hamper measurement and interpretation. For example, strip noise can result in reduced power from the bed, affecting the quality of ice thickness measurements and the characterization of subglacial conditions. Here, we present a method for removing strip noise based on combined wavelet and two-dimensional (2-D) Fourier filtering. First, we implement discrete wavelet decomposition on RES data to obtain multi-scale wavelet components. Then, 2-D discrete Fourier transform (DFT) spectral analysis is performed on components containing the noise. In the Fourier domain, the 2-D DFT spectrum of strip noise keeps its linear features and can be removed with a 'targeted masking' operation. Finally, inverse wavelet transforms are performed on all wavelet components, including strip-removed components, to restore the data with enhanced fidelity. Model tests and field-data processing demonstrate the method removes strip noise well and, incidentally, can remove the strong first reflector from the ice surface, thus improving the general quality of radar data.
Smith AM, Woodward J, Ross N, et al., 2018, Evidence for the long-term sedimentary environment in an Antarctic subglacial lake, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 504, Pages: 139-151, ISSN: 0012-821X
Keen P, Saw K, Rundle N, et al., 2018, A mini-corer for precision sampling of the water-sediment interface in subglacial lakes and other remote aqueous environments, LIMNOLOGY AND OCEANOGRAPHY-METHODS, Vol: 16, Pages: 856-867, ISSN: 1541-5856
Jordan TA, Martin C, Ferraccioli F, et al., 2018, Anomalously high geothermal flux near the South Pole, SCIENTIFIC REPORTS, Vol: 8, ISSN: 2045-2322
Jeofry H, Ross N, Le Brocq A, et al., 2018, Hard rock landforms generate 130 km ice shelf channels through water focusing in basal corrugations, NATURE COMMUNICATIONS, Vol: 9, ISSN: 2041-1723
Rintoul SR, Chown SL, DeConto RM, et al., 2018, Choosing the future of Antarctica (vol 558, 233, 2018), NATURE, Vol: 562, Pages: E5-E5, ISSN: 0028-0836
Siegert MJ, Kennicutt MC, 2018, Governance of the Exploration of Subglacial Antarctica, FRONTIERS IN ENVIRONMENTAL SCIENCE, Vol: 6, ISSN: 2296-665X
Jordan TM, Williams CN, Schroeder DM, et al., 2018, A constraint upon the basal water distribution and thermal state of the Greenland Ice Sheet from radar bed echoes, CRYOSPHERE, Vol: 12, Pages: 2831-2854, ISSN: 1994-0416
Colleoni F, De Santis L, Siddoway CS, et al., 2018, Spatio-temporal variability of processes across Antarctic ice-bed-ocean interfaces (vol 9, 2289, 2018), NATURE COMMUNICATIONS, Vol: 9, ISSN: 2041-1723
Colleoni F, De Santis L, Siddoway CS, et al., 2018, Spatio-temporal variability of processes across Antarctic ice-bed-ocean interfaces, NATURE COMMUNICATIONS, Vol: 9, ISSN: 2041-1723
Jeofry H, Ross N, Corr HFJ, et al., 2018, A new bed elevation model for the Weddell Sea sector of the West Antarctic Ice Sheet, Earth System Science Data, Vol: 10, Pages: 711-725, ISSN: 1866-3508
We present a new digital elevation model (DEM) of the bed, with a 1 km gridding, of the Weddell Sea (WS) sector of the West Antarctic Ice Sheet (WAIS). The DEM has a total area of ∼ 125 000 km2 covering the Institute, Möller and Foundation ice streams, as well as the Bungenstock ice rise. In comparison with the Bedmap2 product, our DEM includes new aerogeophysical datasets acquired by the Center for Remote Sensing of Ice Sheets (CReSIS) through the NASA Operation IceBridge (OIB) program in 2012, 2014 and 2016. We also improve bed elevation information from the single largest existing dataset in the region, collected by the British Antarctic Survey (BAS) Polarimetric radar Airborne Science Instrument (PASIN) in 2010–2011, from the relatively crude measurements determined in the field for quality control purposes used in Bedmap2. While the gross form of the new DEM is similar to Bedmap2, there are some notable differences. For example, the position and size of a deep subglacial trough (∼ 2 km below sea level) between the ice-sheet interior and the grounding line of the Foundation Ice Stream have been redefined. From the revised DEM, we are able to better derive the expected routing of basal water and, by comparison with that calculated using Bedmap2, we are able to assess regions where hydraulic flow is sensitive to change. Given the potential vulnerability of this sector to ocean-induced melting at the grounding line, especially in light of the improved definition of the Foundation Ice Stream trough, our revised DEM will be of value to ice-sheet modelling in efforts to quantify future glaciological changes in the region and, from this, the potential impact on global sea level. The new 1 km bed elevation product of the WS sector can be found at https://doi.org/10.5281/zenodo.1035488.
Jeofry H, Ross N, Corr HFJ, et al., A new bed elevation model for the Weddell Sea sector of the West Antarctic Ice Sheet, Earth System Science Data, ISSN: 1866-3508
Siegert MJ, Jamieson SSR, White D, 2018, Exploration of subsurface Antarctica: uncovering past changes and modern processes, Geological Society, London, Special Publications, Vol: 461, Pages: 1-6, ISSN: 0305-8719
Siegert MJ, 2018, A 60-year international history of Antarctic subglacial lake exploration, Geological Society, London, Special Publications, Vol: 461, Pages: 7-21, ISSN: 0305-8719
Wang B, Sun B, Martin C, et al., 2018, Summit of the East Antarctic Ice Sheet underlain by thick ice-crystal fabric layers linked to glacial–interglacial environmental change, Geological Society, London, Special Publications, Vol: 461, Pages: 131-143, ISSN: 0305-8719
Siegert MJ, Kulessa B, Bougamont M, et al., 2018, Antarctic subglacial groundwater: a concept paper on its measurement and potential influence on ice flow, Geological Society, London, Special Publications, Vol: 461, Pages: 197-213, ISSN: 0305-8719
Jeofry H, Ross N, Corr HFJ, et al., 2018, A deep subglacial embayment adjacent to the grounding line of Institute Ice Stream, West Antarctica, Geological Society, London, Special Publications, Vol: 461, Pages: 161-173, ISSN: 0305-8719
Wrona T, Wolovick MJ, Ferraccioli F, et al., 2018, Position and variability of complex structures in the central East Antarctic Ice Sheet, Geological Society, London, Special Publications, Vol: 461, Pages: 113-129, ISSN: 0305-8719
Beem LH, Cavitte MGP, Blankenship DD, et al., 2018, Ice-flow reorganization within the East Antarctic Ice Sheet deep interior, Geological Society, London, Special Publications, Vol: 461, Pages: 35-47, ISSN: 0305-8719
Morlighem M, Williams CN, Rignot E, et al., 2017, BedMachine v3: Complete Bed Topography and Ocean Bathymetry Mapping of Greenland From Multibeam Echo Sounding Combined With Mass Conservation, GEOPHYSICAL RESEARCH LETTERS, Vol: 44, Pages: 11051-11061, ISSN: 0094-8276
Parrenin F, Cavitte MGP, Blankenship DD, et al., 2017, Is there 1.5-million-year-old ice near Dome C, Antarctica?, CRYOSPHERE, Vol: 11, Pages: 2427-2437, ISSN: 1994-0416
Siegert MJ, 2017, Why Should We Worry About Sea Level Change?, Frontiers for Young Minds, Vol: 5
Roberts J, Curran M, Poynter S, et al., 2017, Correlation confidence limits for unevenly sampled data, COMPUTERS & GEOSCIENCES, Vol: 104, Pages: 120-124, ISSN: 0098-3004
Jordan TM, Cooper MA, Schroeder DM, et al., 2017, Self-affine subglacial roughness: consequences for radar scattering and basal water discrimination in northern Greenland, CRYOSPHERE, Vol: 11, Pages: 1247-1264, ISSN: 1994-0416
Graham FS, Roberts JL, Galton-Fenzi BK, et al., 2017, A high-resolution synthetic bed elevation grid of the Antarctic continent, EARTH SYSTEM SCIENCE DATA, Vol: 9, Pages: 267-279, ISSN: 1866-3508
Roberts J, Galton-Fenzi B, Paolo F, et al., Ocean forced variability of Totten Glacier mass loss, Special Publication - Geological Society of London, ISSN: 0305-8719
A large volume of the East Antarctic Ice Sheet drains through the Totten Glacier (TG) and is thought to be a potential source of substantial global sea level rise over the coming centuries. We show the flow and surface height of floating part of TG, which buttresses the grounded component, have varied substantially over two decades (1989–2011), with variations in surface height and basal melt rates highly anti-correlated (r=0.70, p<0.05). Coupled glacier/ice-shelf simulations confirm ice flow and thickness respond to both basal melting of the ice shelf and grounding on bed obstacles. We conclude the observed variability of TG is primarily ocean-driven and enhanced ice-sheet dynamism, leading to upstream grounded ice loss, will occur from the region with ocean warming.
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