A5070900574- Cryospheric studies and observations
- Winter Sports Injuries and Performance
- Arctic and Antarctic ice dynamics
- Geochemistry and Geologic Mapping
- Climate change and permafrost
- Landslides and related hazards
- Geology and Paleoclimatology Research
- Polar Research and Ecology
- Methane Hydrates and Related Phenomena
- Water Quality and Resources Studies
- Geophysics and Gravity Measurements
- Hydrocarbon exploration and reservoir analysis
- Geological and Geochemical Analysis
- Groundwater flow and contamination studies
- Soil Geostatistics and Mapping
- Atmospheric and Environmental Gas Dynamics
- Geological Modeling and Analysis
- Radioactive element chemistry and processing
- Icing and De-icing Technologies
- Mineral Processing and Grinding
- Groundwater and Isotope Geochemistry
- Spacecraft Design and Technology
- Meteorological Phenomena and Simulations
- Oceanographic and Atmospheric Processes
- Soil Moisture and Remote Sensing
The University of Melbourne
2022-2025
Lancaster University
2019-2024
Centre for Polar Observation and Modelling
2015-2024
University of Iceland
2021
University of Leeds
2011-2019
European Space Research Institute
2018
University of Edinburgh
2007-2012
United States Geological Survey
1987-1995
Denver Federal Center
1987-1995
Research & Development Institute
1992
We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, models surface mass balance glacial isostatic adjustment to estimate the Earth's polar ice sheets. find that there is good agreement between different methods--especially in Greenland West Antarctica--and combining leads greater certainty. Between 1992 2011, sheets Greenland, East Antarctica, Antarctic Peninsula changed by -142 ± 49, +14 43, -65 26, -20...
Fluctuations in Antarctic Ice Sheet elevation and mass occur over a variety of time scales, owing to changes snowfall ice flow. Here we disentangle these signals by combining 25 years satellite radar altimeter observations regional climate model. From measurements, patterns change that are strongly associated with glaciological events emerge. While the majority sheet has remained stable, 24% West Antarctica is now state dynamical imbalance. Thinning Pine Island Thwaites glacier basins...
We use 3 years of Cryosat-2 radar altimeter data to develop the first comprehensive assessment Antarctic ice sheet elevation change. This new set provides near-continuous (96%) coverage entire continent, extending within 215 km South Pole and leading a fivefold increase in sampling coastal regions where vast majority all losses occur. Between 2010 2013, West Antarctica, East Peninsula changed mass by −134 ± 27, −3 36, −23 18 Gt yr−1, respectively. In signals imbalance are present areas that...
Abstract We map recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal (monthly) resolution using CryoSat‐2 altimetry. After correcting for the impact of changing snowpack properties associated with unprecedented surface melting in 2012, we find good agreement (3 cm/yr bias) airborne measurements. With aid regional climate firn modeling, compute records mass evolution, which correlate ( R = 0.96) monthly satellite gravimetry reveal glacier dynamic imbalance. During...
Abstract. Ice losses from the Greenland and Antarctic ice sheets have accelerated since 1990s, accounting for a significant increase in global mean sea level. Here, we present new 29-year record of sheet mass balance 1992 to 2020 Sheet Mass Balance Inter-comparison Exercise (IMBIE). We compare combine 50 independent estimates derived satellite observations temporal changes flow, volume, Earth's gravity field. Between 2020, contributed 21.0±1.9 mm level, with rate loss rising 105 Gt yr−1...
We use ground‐based and satellite observations to detect large diurnal longer‐period variations in the flow of Greenland Ice Sheet (GrIS) during late summer that are strongly coupled with changes its surface hydrology. The signals associated periodic melting, episodic drainage supra‐glacial lakes. velocity doubles around 2 hours after peak daily melting returns approximately wintertime levels 12 afterwards, demonstrating an intimate link between basal During summer, ice sheet accelerates by...
Abstract. We present a new digital elevation model (DEM) of the Antarctic ice sheet and shelves based on 2.5×108 observations recorded by CryoSat-2 satellite radar altimeter between July 2010 2016. The DEM is formed from spatio-temporal fits to measurements accumulated within 1, 2, 5 km grid cells, posted at modal resolution 1 km. Altogether, 94 % grounded 98 floating are observed, remaining cells north 88∘ S interpolated using ordinary kriging. median root mean square difference 2.3×107...
Abstract. Systematically monitoring Greenland's outlet glaciers is central to understanding the timescales over which their flow and sea level contributions evolve. In this study we use data from new Sentinel-1a/b satellite constellation generate 187 velocity maps, covering four key in Greenland: Jakobshavn Isbræ, Petermann Glacier, Nioghalvfjerdsfjorden, Zachariæ Isstrøm. These provide a high temporal resolution record (6-day averaged solutions) of each glacier's evolution since 2014,...
Abstract Runoff from the Greenland Ice Sheet has increased over recent decades affecting global sea level, regional ocean circulation, and coastal marine ecosystems, it now accounts for most of contemporary mass imbalance. Estimates runoff are typically derived climate models because satellite records have been limited to assessments melting extent. Here, we use CryoSat-2 altimetry produce direct measurements Greenland’s variability, based on seasonal changes in ice sheet’s surface...
Remote sensing technologies are integral to monitoring the mountain cryosphere in a warming world. Satellite missions and field-based platforms have transformed understanding of processes driving changes glacier dynamics, snow cover, lake evolution, associated emergence hazards (e.g. avalanches, floods, landslides). Sensors becoming more bespoke, with innovation being driven by commercial sector, image repositories frequently open access, leading democratisation data analysis interpretation....
Abstract Mass balance assessments of the East Antarctic ice sheet (EAIS) are highly sensitive to changes in firn thickness, causing substantial disagreement estimates its contribution sea‐level. To better constrain uncertainty recent thickness changes, we develop an ensemble 54 model scenarios evolution between 1992 and 2017. Using statistical emulation firn‐densification models, quantify impact compaction formulation, differing climatic forcing, surface snow density on evolution. At basin...
Abstract. Quantifying the extent and distribution of supraglacial hydrology, i.e. lakes streams, is important for understanding mass balance Antarctic ice sheet its consequent contribution to global sea-level rise. The existence meltwater on surface has potential affect shelf stability grounded flow through hydrofracturing associated delivery bed. In this study, we systematically map all observable streams in West Antarctica by applying a semi-automated Dual-NDWI (normalised difference water...
Abstract Ice dynamic change is the primary cause of mass loss from Antarctic Sheet, thus it important to understand processes driving ice-ocean interactions and timescale on which major can occur. Here we use satellite observations measure a rapid increase in speed collapse ice shelf fronting Cadman Glacier absence surface meltwater ponding. Between November 2018 December 2019 increased by 94 ± 4% (1.47 0.6 km/yr), discharge 0.52 0.21 Gt/yr, calving front retreated 8 km with thinning...
Abstract. Supraglacial lakes form on the Greenland ice sheet in melt season (May to October) when meltwater collects surface depressions ice. can act as a control dynamics since, given large enough volume of water and favourable stress regime, hydrofracture lake occur, which enables transfer from bedrock, where it lubricate base. The depth (and thus volume) these is typically estimated by applying radiative equation (RTE) optical satellite imagery. This method be used at scale across entire...
Ice loss from the Greenland and Antarctic ice sheets currently contributes one third of global sea level rise, yet monitoring their complex coastal regions remains a challenge. One principal methods for determining sheet imbalance is satellite radar altimetry, which provides 30-year record surface elevation change. Over rugged topography, however, altimeter echo returned often complex, with multiple distinct reflections degrading accuracy measurements. Here, we present new processing...
Abstract We analyze data acquired by the CryoSat‐2 interferometric radar altimeter and demonstrate its novel capability to track topographic features on Antarctic Ice Sheet. map perimeter depth of a 260 km 2 surface depression above an subglacial lake (SGL) and, in combination with Ice, Cloud land Elevation Satellite laser altimetry, chart decadal changes SGL volume. During 2007–2008, between 4.9 6.4 3 water drained from SGL, peak discharge exceeded 160 m s −1 . The flood was twice as large...
Major changes are occurring across the North Atlantic climate system, including in atmosphere, ocean and cryosphere, many observed unprecedented instrumental records. As directly affect air quality of surrounding continents, it is important to fully understand how why taking place, not least predict region will change future. To this end, article characterizes recent region, especially period 2005–2016, different aspects system including: atmospheric circulation; composition; clouds...
Abstract We use satellite observations to document rapid acceleration and ice loss from a formerly slow‐flowing, marine‐based sector of Austfonna, the largest cap in Eurasian Arctic. During past two decades, discharge has increased 45‐fold, velocity regime switched predominantly slow (~ 10 1 m/yr) fast 3 flow, rates thinning have exceeded 25 m/yr. At time widespread dynamic activation, parts terminus may been near floatation. Subsequently, imbalance propagated 50 km inland within 8 summit....
Abstract The contribution of the Greenland ice sheet to sea-level rise has accelerated in recent decades. Subglacial lake drainage events can induce an dynamic response—a process that been observed Antarctica, but not yet Greenland, where presence subglacial lakes only recently discovered. Here we investigate water flow paths from a lake, which drained beneath 2011. Our observations suggest was fed by surface meltwater flowing down nearby moulin, and draining reached margin via tunnel....