A5058587151- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Winter Sports Injuries and Performance
- Landslides and related hazards
- Arctic and Antarctic ice dynamics
- Climate change and permafrost
- Polar Research and Ecology
- Methane Hydrates and Related Phenomena
- Meteorological Phenomena and Simulations
- Icing and De-icing Technologies
- Geological formations and processes
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
- Geological Modeling and Analysis
- Geological Studies and Exploration
- Pleistocene-Era Hominins and Archaeology
- Climate variability and models
- Astro and Planetary Science
- Scientific Research and Discoveries
- Underwater Acoustics Research
- Fluid Dynamics and Vibration Analysis
- Geophysical Methods and Applications
- Geotechnical Engineering and Underground Structures
- Atmospheric and Environmental Gas Dynamics
- Adventure Sports and Sensation Seeking
British Antarctic Survey
2014-2025
Natural Environment Research Council
2007-2018
Google (United States)
2006
University of Edinburgh
1987-1990
Abstract. We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor subglacial bed elevation Antarctic south 60° S. derived these using data from variety sources, including many substantial surveys completed since original Bedmap compilation (Bedmap1) in 2001. In particular, Bedmap2 ice thickness grid is made 25 million measurements, over two orders magnitude more than were used Bedmap1. most parts Antarctica landscape visible much...
Experiments beneath Breidamerkurjökull in Iceland have led to development of flow laws for the subglacial till, relating strain rate shear stress and effective pressure assuming either Bingham fluid or nonlinearly viscous behavior. Water pressures till are less than ice it is suggested that this may lead infiltration into sediment, which inhibits sliding at ice/sediment interface. Where water equal near pressures, does not occur result. A one‐dimensional theory deformation developed...
Abstract Predictions of marine ice-sheet behaviour require models able to simulate grounding-line migration. We present results an intercomparison experiment for plan-view models. Verification is effected by comparison with approximate analytical solutions flux across the grounding line using simplified geometrical configurations (no lateral variations, no buttressing effects from drag). Perturbation experiments specifying spatial variation in basal sliding parameters permitted evolution...
Abstract. We present the results of first ice sheet model intercomparison project for higher-order and full-Stokes models. These models are compared verified in a series six experiments which one has an analytical solution obtained from perturbation analysis. The applied to both 2-D 3-D geometries; five steady-state diagnostic, time-dependent prognostic solution. All participating give that close agreement. A clear distinction can be made between those solve full system equations. show much...
Free-surface thin-film flows can principally be described by two types of models. Lubrication models assume that shear stresses are dominant in the force balance flow and appropriate where there is little or no slip at base flow. Conversely, membrane 'free-film' situations rapid normal (or extensional) play a significant role balance. In some physical applications, notably glaciology, both slow occur within same fluid film. order to capture dynamics single model describes entire film, hybrid...
Abstract. Predictions of marine ice-sheet behaviour require models that are able to robustly simulate grounding line migration. We present results an intercomparison exercise for models. Verification is effected by comparison with approximate analytical solutions flux across the using simplified geometrical configurations (no lateral variations, no effects buttressing). Unique steady state positions exist ice sheets on a downward sloping bed, while hysteresis occurs overdeepened and stable...
Abstract. Two ice-dynamic transitions of the Antarctic ice sheet – boundary grounded features and freely-floating are mapped at 15-m resolution by participants International Polar Year project ASAID using customized software combining Landsat-7 imagery ICESat/GLAS laser altimetry. The is 53 610 km long; 74 % abuts to floating shelves or outlet glaciers, 19 adjacent open sea-ice covered ocean, 7 terminates on land. boundary, called here hydrostatic line, most landward position that expresses...
Locally grounded features in ice shelves, called rises and rumples, play a key role buttressing discharge from the Antarctic Ice Sheet regulating its contribution to sea level. typically rise several hundreds of meters above surrounding shelf; shelf flow is diverted around them. On other hand, flows across which only few tens shelf. contain rich histories deglaciation climate that extend back over timescales ranging millennia beyond last glacial maximum. Numerical model results have shown...
The BRITICE‐CHRONO consortium of researchers undertook a dating programme to constrain the timing advance, maximum extent and retreat British–Irish Ice Sheet between 31 000 15 years before present. campaign across Ireland Britain their continental shelves, North Sea included 1500 days field investigation yielding 18 km marine geophysical data, 377 cores sea floor sediments, geomorphological stratigraphical information at 121 sites on land; generating 690 new geochronometric ages. These...
Abstract We present Bedmap3, the latest suite of gridded products describing surface elevation, ice-thickness and seafloor subglacial bed elevation Antarctic south 60 °S. Bedmap3 incorporates adds to all post-1950s datasets previously used for Bedmap2, including 84 new aero-geophysical surveys by 15 data providers, an additional 52 million points 1.9 line-kilometres measurement. These efforts have filled notable gaps in major mountain ranges deep interior East Antarctica, along West...
A computational analysis of the accuracy different approximations to Stokes equations for momentum balance used in ice sheet modeling is performed by solving a particular tractable form appropriate small perturbations surface, describing uniform flow with Glen rheology on an infinitely long and broad section. The approximants comprise shallow approximation various schemes incorporating longitudinal stresses and, one case, horizontal gradient plane shear stresses. simplifications lead...
Abstract. We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor subglacial bed elevation Antarctic south 60° S. derived these using data from variety sources, including many substantial surveys completed since original Bedmap compilation (Bedmap1) in 2001. In particular, Bedmap2 ice thickness grid is made 25 million measurements, over two orders magnitude more than were used Bedmap1. most parts Antarctica landscape visible much...
Abstract. The recovery of a 1.5 million yr long ice core from Antarctica represents keystone our understanding Quaternary climate, the progression glaciation over this time period and role greenhouse gas cycles in progression. Here we tackle question where such may still be found Antarctic sheet. We can show that old is most likely to exist plateau area East sheet (EAIS) without stratigraphic disturbance should able recovered after careful pre-site selection studies. Based on simple heat...
[1] Bedrock uplift in Antarctica is dominated by a combination of glacial isostatic adjustment (GIA) and elastic response to contemporary mass change. Here, we present spatially extensive GPS observations Antarctic bedrock uplift, using 52% more stations than previous studies, giving enhanced coverage, with improved precision. We observe rapid the northern Peninsula. After considering rebound, data suggests that modeled or empirical GIA signals are often over-estimated, particularly...
Increase in ice‐shelf melting is generally presumed to have triggered recent coastal ice‐sheet thinning. Using a full‐Stokes finite element model which includes proper description of the grounding line dynamics, we investigate impact below ice shelves. We argue that influence on dynamics induces complex response, and first naive view inevitably leads loss grounded erroneous. demonstrate acts directly magnitude buttressing force by modifying both area experiencing lateral resistance velocity,...
Abstract Accurate dynamical models of the Antarctic ice sheet with carefully specified initial conditions and well‐calibrated rheological parameters are needed to forecast global sea level. By adapting an inverse method previously used in electric impedance tomography, we infer present‐day flow speeds within sheet. This inversion uses satellite observations surface velocity, snow accumulation rate, rate change elevation estimate basal drag coefficient stiffness parameter that influences...
Abstract. We present a 2700-year annually resolved chronology and snow accumulation history for the Roosevelt Island Climate Evolution (RICE) ice core, Ross Ice Shelf, West Antarctica. The core adds information on past changes in an otherwise poorly constrained sector of timescale was constructed by identifying annual cycles high-resolution impurity records, it constitutes top part Core Chronology 2017 (RICE17). Validation volcanic methane matching to WD2014 from WAIS Divide shows that two...
Abstract. One of the key components this research has been mapping Antarctic bed topography and ice thickness parameters that are crucial for modelling flow hence predicting future loss ensuing sea level rise. Supported by Scientific Committee on Research (SCAR), Bedmap3 Action Group aims not only to produce new gridded maps international scientific community, but also standardize make available all geophysical survey data points used in producing Bedmap products. Here, we document latest...
Abstract A substantial proportion of the glacial sediments East Anglia, England, are chaotic and highly deformed. This has been attributed to (a) direct glaciotectonic deformation or (b) slumping glaciomarine sediments. We show that interpretation leads a classification subglacial deposits into sites ‘constructional deformation’, where little no erosion preglacial occurred styles preserved moving up in sequence, ‘excavational deformational superimposed on each other. By using glaciological...
Abstract Using the finite-element code Elmer, we show that full Stokes modeling of ice-sheet/ice-shelf transition propose can give consistent predictions grounding-line migration. Like other marine ice-sheet models our approach is highly sensitive to chosen mesh resolution. However, with a grid size down <5 km in vicinity grounding line, start be robust because: (1) whatever (<5 km) steady-state position sensibly same (6 standard deviation), and (2) grid-size refinement line (200 m),...