A5049047601- Cryospheric studies and observations
- Winter Sports Injuries and Performance
- Arctic and Antarctic ice dynamics
- Climate change and permafrost
- Landslides and related hazards
- Geology and Paleoclimatology Research
- Remote Sensing and LiDAR Applications
- 3D Surveying and Cultural Heritage
- Polar Research and Ecology
- Geophysics and Gravity Measurements
- Methane Hydrates and Related Phenomena
- Satellite Image Processing and Photogrammetry
- Adventure Sports and Sensation Seeking
- Soil Moisture and Remote Sensing
- Offshore Engineering and Technologies
- Geological Studies and Exploration
- Hydrocarbon exploration and reservoir analysis
- GNSS positioning and interference
- Geological Modeling and Analysis
- Inertial Sensor and Navigation
- Soil Geostatistics and Mapping
- Climate variability and models
- Coastal and Marine Management
- Arctic and Russian Policy Studies
- Aerospace Engineering and Energy Systems
Queen's University
2018-2024
Swansea University
2006-2016
University of Leeds
2000-2007
Durham University
2007
University of Wales
2007
Institut National de la Recherche Scientifique
2007
Synchronous acceleration and thinning of southeast (SE) Greenland glaciers during the early 2000s was main contributor that resulted in doubling annual discharge from ice sheet. We show this followed by a synchronized widespread slowdown same glaciers, many cases associated with decrease rates, we propose sheet–ocean interactions are first‐order regional control on these recent mass changes. Sea surface temperature mooring data preceding dynamic coincides brief decline cold East Coastal...
Geodetic measurements indicate that a number of glaciers in western Svalbard ranging size from 5–1000 km 2 are losing mass at an accelerating rate. The average thinning rate for Midtre Lovénbreen, the glacier with best data coverage, has increased steadily since 1936. Thinning rates 2003–2005 more than 4 times first measurement period 1936–1962 and significantly greater presented previously. On Slakbreen, latest 1990–2003 1961–1977. several along previously measured airborne lidar profile...
The rapid drainage of supraglacial lakes around the ablation zone Greenland Ice Sheet forms an important link between water at surface and ice sheet base, allowing meltwater to reach bed hence increase glacial velocity. conduits formed by lake drainages may remain open during remainder melt season providing a pathway for further base. We investigated behavior from all regions period 2005–2009. mapped evolution 2600 3704 MODIS images detecting mean 263 events per year, which 61% occurred in...
Overall mass loss from the Greenland ice sheet nearly doubled during early 2000s resulting in an increased contribution to sea-level rise, with this step-change being mainly attributed widespread frontal retreat and accompanying dynamic thinning of tidewater glaciers. Changes glacier calving-front positions are easily derived remotely sensed imagery provide a record change. However, ice-sheet-wide studies calving fronts have been either spatially or temporally limited. In study multiple were...
This paper is concerned with the application of automated digital photogrammetry, using 1:3000 scale photography, to complex, natural landform surfaces, typical interest geomorphologists. It assesses quality results obtained a relatively cheap and readily available area based stereomatching package, in terms precision, accuracy external reliability. Precision investigated reference confidence that can be placed individual matches. Accuracy evaluated specially collected, independent datasets...
Abstract. Calving is an important mass-loss process for many glaciers worldwide, and has been assumed to respond a variety of environmental influences. We present grounded, flowline tidewater glacier model using physically-based calving mechanism, applied Helheim Glacier, eastern Greenland. By qualitatively examining both modelled size frequency events, the subsequent dynamic response, found realistically reproduce key aspects observed behaviour. Experiments explore four variables which have...
During summer 2013 we installed a network of 19 GPS nodes at the ungrounded margin Helheim Glacier in southeast Greenland together with three cameras to study iceberg calving mechanisms. The collected data rates up every 7 s and was designed be robust loss as glacier calved. Data collection covered 55 days, many survived locations right front time calving. observations included number significant events, consequence retreated ~1.5 km. provide real-time, high-frequency unprecedented proximity...
Abstract Interactions between glaciers and the ocean are key for understanding dynamics of cryosphere in climate system. Here we investigate role hydrostatic forces glacier calving. We develop a mathematical model to account elastic deformation response three effects: (i) marine lake‐terminating tend enter water with nonzero slope, resulting upward flexure around grounding line; (ii) horizontal pressure imbalances at terminus known cause in‐plane stresses downward acting torque; (iii)...
Abstract. Changes in the volume and extent of land ice Svalbard archipelago have been subject considerable research since their sensitivity to changes climate was first noted. However, measurement these is often necessarily based on point or profile measurements which may not be representative if extrapolated a whole catchment region. Combining high-resolution elevation data from contemporary laser-altimetry surveys archived aerial photography makes it possible measure historical across...
Abstract Photogrammetric processing of archival stereo imagery offers the opportunity to reconstruct glacier volume changes for regions where no such data exist, and better constrain contribution sea-level rise from small glaciers ice caps. The ability derive digital elevation model (DEM) measurements photogrammetry relies on good-quality, well-distributed ground reference data, which may be difficult acquire. This study shows that ground-control points (GCPs) can identified extracted...
Movers and shakers When the edge of an ice sheet breaks off falls into sea (calves), remaining section moves backward down can suffer a glacial earthquake. Murray et al. studied calving from Greenland's Helheim Glacier. The forces that cause change in motion at its terminus also trigger accompanying earthquakes. Because these seismic signals be detected by instruments located all over globe, it should possible to use earthquakes as proxies for glacier calving. Science , this issue p. 305
Supraglacial lake drainage events are common on the Greenland ice sheet. Observations west coast typically show an up-glacier progression of as annual melt extent spreads inland. We use a suite remote sensing and modeling techniques in order to study series lakes water-filled crevasses within 20 km terminus Helheim Glacier, southeast Greenland. Automatic classification surface water areas shows down-glacier drainage, which occurs majority years between 2007 2014. demonstrate that linear...
Abstract Forestalling the decline of global biodiversity requires urgent and transformative action at all levels government society, particularly in Arctic Ocean adjacent seas where rapid changes are already underway. Amid growing scientific support mounting pressure, majority nations have committed to most ambitious conservation targets yet. However, without an approach that inclusively equitably reconciles sustainable ocean use, these will likely go unmet. Here, we present ArcNet: a...
Abstract Research has shown the importance of measuring topography for surface change detection and that use remote sensing methods is ideal this application. A prerequisite a historical data‐set covers time period interest. Many topographic data collection such as lidar are relatively recent developments therefore cannot provide records longer than about decade. Alternatively, aerial photography been in common since early 20th century archives upwards 50 years not uncommon. While...
Abstract Uncertainties in estimates of glacier and ice-cap contribution to sea-level rise exist part due poor quantification mass-balance errors, particularly those resulting from extrapolation sparse measurements. Centre-line data are often assumed be representative the as a whole, with little attention paid errors or their effect on estimates. Here we present detailed digital elevation model (DEM) measurements glacier-wide changes over last ~40 years at two glaciers Svalbard, Norwegian...
Abstract. The behaviour of supraglacial lakes on the Greenland Ice Sheet has attracted a great deal focus, specifically with regard to their fast drainage through hydrofracturing ice sheet base. However, previous study shown that this mode accounts for only 13% Sheet. No published work date studied what happens those do not drain suddenly. We present here three possible modes by which can disappear from sheet, will have strongly contrasting effects glacial dynamics and water budget. Around...
This paper provides an overview of a wide area wireless sensor network that was deployed on the calving front Helheim Glacier in Greenland during summer 2013. The purpose to measure flow rate glacier using accurate satellite positioning data. challenge this extreme environment collect data real time at edge glacier. achieved solar powered 2.4-GHz Zigbee operated novel hybrid cellular/mesh access architecture consisting ice nodes communicating with base stations placed rock adjacent highly...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Glaciated regions are known to be particularly sensitive climate change. Historical archives of glacier volume change important, as they provide context for present-day changes. Although photogrammetric exist many regions, their usefulness is often limited by a lack contemporary ground control. High quality digital elevation models (DEMs) underpin range analysis activities. This paper presents...
Fridtjovbreen, Svalbard, is a partially tidewater-terminating glacier that started 7-year surge during the 1990s. Flow peaked 1996 and no front was apparent. We use two pre-surge (1969 1990) post-surge (2005) digital elevation models (DEMs) together with bed DEM to quantify volume changes iceberg calving surge, calculate in hypsometry, investigate trigger. Between 1969 1990, lost 5% of its volume, retreated 530 m thinned by up 60 lower elevations while thickening 20 higher elevations. During...
Abstract This paper assesses the feasibility of estimating water levels using digital photogrammetry. A common problem during an extreme flood event is that automated level recorders do not record highest levels, as a result instrument malfunctioning. explores two possible solutions to this based upon data acquired synoptic remote sensing methods. The first method requires: (a) high‐resolution elevation (for example, in form model for floodplain); and (b) information on planimetric position...
Digital elevation models (DEMs) are prone to error that, as they can never be entirely eliminated, must managed effectively.Thus, it is important understand the nature of and their sources, especially in context intended use a DEM.This paper investigates effects that expected when common DEM errors propagate through scaling analysis.The investigated include those associated with perturbation camera exterior orientation parameters, focal length, image coordinates, which were simulated...
Structural glaciological maps can be used to study the structural evolution and past dynamics of glaciers. The map described here documents glacier-wide characteristics Austre Brøggerbreen, a c. 12 km2 predominantly cold-based valley glacier in northwest Svalbard. reveals that is dominated by deep-penetrating fractures are now relict (crevasse traces). These structures indicate that, despite being relatively inactive at present, was once much more dynamic, presumably during its last advance...
Abstract Airborne topographic data collection requires removal of errors that arise due to surface features obstruct the ground from sensor. Typically, this has been based on manual correction and/or automated filtering. To some degree, latter provided a method for identifying and removing unwanted obstructions in large data‐sets. However, algorithms used are unintelligent they cannot reliably differentiate between various types ground. If coincident optical support imagery is available, use...