A5072186841- Cryospheric studies and observations
- Climate change and permafrost
- Arctic and Antarctic ice dynamics
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Landslides and related hazards
- Winter Sports Injuries and Performance
- Radiation Detection and Scintillator Technologies
- Soil Moisture and Remote Sensing
- Nuclear physics research studies
- Particle Detector Development and Performance
- Radiation Therapy and Dosimetry
- Methane Hydrates and Related Phenomena
- Geophysics and Gravity Measurements
- Wireless Communication Networks Research
- Astrophysics and Cosmic Phenomena
- Synthesis of Organic Compounds
- Geophysical Methods and Applications
- Nuclear Materials and Properties
- Icing and De-icing Technologies
- Advanced Wireless Communication Techniques
- Magnetic confinement fusion research
- Antenna Design and Optimization
- Atmospheric chemistry and aerosols
- Masonry and Concrete Structural Analysis
Commonwealth Scientific and Industrial Research Organisation
2025
Environment and Climate Change Canada
2015-2024
Lawrence Berkeley National Laboratory
2024
UiT The Arctic University of Norway
2023
University of Manitoba
2023
Centre for Polar Observation and Modelling
2023
University of Bristol
2023
Ochsner Medical Center
2023
Lawrence Livermore National Laboratory
2021-2022
University of California, Davis
2021-2022
Recent advancement in the understanding of snow-microwave interactions has helped to isolate considerable potential for radar-based retrieval snow water equivalent (SWE). There are however, few datasets available address spatial uncertainties, such as influence microstructure, at scales relevant space-borne application. In this study we introduce measurements from SnowSAR, an airborne, dual-frequency (9.6 and 17.2 GHz) synthetic aperture radar (SAR), evaluate high resolution (10 m)...
Abstract The European Space Agency's CryoSat‐2 satellite mission provides radar altimeter data that are used to derive estimates of sea ice thickness and volume. These crucial understanding recent variability changes in Arctic ice. Sea retrievals at the frequency require accurate measurements freeboard, assumed be attainable when main scattering horizon is snow/sea interface. Using an extensive snow thermophysical property dataset from late winter conditions Canadian Arctic, we examine role...
Abstract. Seasonal snow cover is the largest single component of cryosphere in areal extent, covering an average 46 × 106 km2 Earth's surface (31 % land area) each year, and thus important expression driver climate. In recent years, Northern Hemisphere spring has been declining at about same rate (∼ −13 per decade) as Arctic summer sea ice. More than one-sixth world's population relies on seasonal snowpack glaciers for a water supply that likely to decrease this century. Snow also critical...
Abstract During the 2010/11 boreal winter, a distributed set of backscatter measurements was collected using ground-based Ku-band (17.2 GHz) scatterometer system at 26 open tundra sites. A standard snow-sampling procedure completed after each scan to evaluate local variability in snow layering, depth, density and water equivalent (SWE) within field view. The shallow depths large basal depth hoar encountered presented an opportunity under previously untested conditions. Strong response found...
Current methods for retrieving SWE (snow water equivalent) from space rely on passive microwave sensors. Observations are limited by poor spatial resolution, ambiguities related to separation of snow microstructural properties the total mass, and signal saturation when is deep (~>80 cm). The use SAR (Synthetic Aperture Radar) at suitable frequencies has been suggested as a potential observation method overcome coarse resolution Nevertheless, sensors operating are, up now, unavailable....
In this paper, we develop a radar snow water equivalent (SWE) retrieval algorithm based on parameterized forward model of bicontinuous dense media radiative transfer (Bic-DMRT). The is retrieving the absorption loss snowpack which directly proportional to SWE. algorithm, Bic-DMRT first applied generate lookup table (LUT) backscattering at X- and Ku-band. Regression training LUT transform dual-frequency backscatter into functions two parameters: scattering albedo X-band background subtracted...
Abstract. Since 2009, the ultra-wideband snow radar on Operation IceBridge (OIB; a NASA airborne mission to survey polar ice covers) has acquired data in annual campaigns conducted during Arctic and Antarctic springs. Progressive improvements hardware processing methodologies have led improved quality for subsequent retrieval of depth. Existing algorithms differ way air–snow (a–s) snow–ice (s–i) interfaces are detected localized returns how system limitations addressed (e.g., noise,...
Abstract. Local-scale variations in snow density and layering on Arctic sea ice were characterized using a combination of traditional pit SnowMicroPen (SMP) measurements. In total, 14 sites evaluated within the Canadian Archipelago Ocean both first-year (FYI) multi-year (MYI) ice. Sites contained multiple pits with coincident SMP profiles as well unidirectional transects. An existing model was recalibrated manual cutter measurements (n=186) to identify best-fit parameters for observed...
Abstract. Spatial variability in snowpack properties negatively impacts our capacity to make direct measurements of snow water equivalent (SWE) using satellites. A comprehensive data set microstructure (94 profiles at 36 sites) and layer thickness (9000 vertical across nine trenches) collected over two winters Trail Valley Creek, NWT, Canada, was applied synthetic radiative transfer experiments. This allowed for robust assessment the impact estimation accuracy unknown microstructural...
For northern countries like Canada, seasonal snow cover is a key component of the water cycle and commodity high importance to public safety, economic sustainability, ecosystem function. Despite this importance, equivalent (SWE - amount stored by snow) information from existing surface observing networks satellite data does not adequately address most user needs. To gap, new synthetic aperture radar (SAR) mission capable providing on terrestrial SWE at previously unrealized spatial...
Abstract. Observed and modelled landfast ice thickness variability trends spanning more than 5 decades within the Canadian Arctic Archipelago (CAA) are summarized. The observed sites (Cambridge Bay, Resolute, Eureka Alert) represent some of Arctic's longest records thickness. end-of-winter (maximum) (1957–2014) were statistically significant at Cambridge Bay (−4.31 ± 1.4 cm decade−1), (−4.65 1.7 decade−1) Alert (−4.44 1.6 −1) but not Resolute. Over 50+-year record, thinned by ∼ 0.24–0.26 m...
Abstract In April 2017, we collected unique, extensive in situ data of sea ice and snow thickness. At 10 sampling sites, located under a CryoSat‐2 overpass, between Ellesmere Island 87.1°N mean modal total thicknesses ranged 2 to 3.4 m 1.8 2.9 m, respectively. Coincident 0.3 0.47 (mean) 0.1 0.5 (mode). The profile spanned the complete multiyear zone Lincoln Sea, into first‐year farther north. Complementary thickness measurements near North Pole showed 0.31 m. Compared with scarce from other...
A winter time series of ground-based (X- and Ku-bands) scatterometer spaceborne synthetic aperture radar (SAR) (C-band) fully polarimetric observations coincident with in situ snow ice measurements are used to identify the dominant scattering mechanism bubbled freshwater lake Hudson Bay Lowlands near Churchill, Manitoba. Scatterometer two physical sources backscatter from cover: snow-ice ice-water interfaces. Backscatter at all frequencies show increases interface prior inclusion tubular...
Abstract. Snowpack microstructure controls the transfer of heat to, as well temperature of, underlying soils. In situ measurements snow and soil properties from four field campaigns during two winters (March November 2018, January March 2019) were compared to an ensemble CLM5.0 (Community Land Model) simulations, at Trail Valley Creek, Northwest Territories, Canada. Snow micropenetrometer profiles allowed for snowpack density thermal conductivity be derived higher vertical resolution (1.25...
Mercury is a highly toxic trace metal that readily biomagnifies in food webs where it inaccessible to current bioremediation methods. Animals could potentially be engineered detoxify mercury within their clean up impacted ecosystems. We demonstrate invertebrate (Drosophila melanogaster) and vertebrate (Danio rerio) animal models can express organomercurial lyase (MerB) mercuric reductase (MerA) from Escherichia coli demethylate methylmercury remove biomass as volatile elemental mercury. The...
The University of Waterloo scatterometer, which is a system developed for observation snow and ice properties, described. composed two frequency-modulated continuous-wave radars operating at center frequencies 17.2 9.6 GHz. A field-deployable platform allows rapid setup remote sites under harsh environmental conditions. two-axis positioning moves the radar beam across user-programmable range azimuth (±180°) elevation angles (15°-105°). Typical scans 60° angular width generate between 21 586...
Abstract We evaluate Operation IceBridge (OIB) “quick‐look” snow depth on sea ice retrievals using in situ measurements taken over immobile first‐year (FYI) and multiyear (MYI) during March of 2014. Good agreement was found undeformed FYI (−4.5 cm mean bias) with reduced deformed (−6.6 bias). Over MYI, the bias −5.7 cm, but 54% were discarded by OIB retrieval process as compared to only 10% FYI. Footprint scale analysis revealed a root‐mean‐square error (RMSE) 6.2 RMSE 10.5 17.5 more complex...
Within the framework of European Space Agency (ESA) activities, several campaigns were carried out in last decade with purpose exploiting capabilities multifrequency synthetic aperture radar (SAR) data to retrieve snow information. This article presents results obtained from ESA SnowSAR airborne campaigns, between 2011 and 2013 on boreal forest, tundra alpine environments, selected as representative different regimes. The aim this study was assess capability X- Ku-bands SAR retrieving...
We present new high-resolution snow depth data on Arctic sea ice derived from airborne microwave radar measurements the IceBird campaigns of Alfred Wegener Institute (AWI) together with a retrieval method using signal peakiness based an intercomparison exercise colocated at different altitudes. aim to demonstrate capabilities and potential improvements data, which were acquired lower altitude (200 ft) slower speed (110 kn) had smaller footprint size (2-m diameter) than previous data. So far,...
This study is the first assessment of winter season backscatter (σ°) evolution for snow-covered lake ice observed by X(9.6 Gnz) and Ku-band (17.2 ground-based scatterometers (UW-SCAT), collected during Canadian Snow Ice Experiment in 2010-2011. The σ° three cover scenarios simulated using a bubbled model. range resolution UW-SCAT provides separation interaction at snow-ice interface (P1), within volume ice-water (P2). cores extracted end observation period indicate P2 increase approximately...
Current satellite observing systems lack the capability to derive terrestrial snow water equivalent (SWE, amount of liquid stored in solid form by snow) at spatial resolution, synoptic sensitivity, global coverage, and accuracy required for operational environmental monitoring, services, prediction. The combination revisit time, measurement sensitivity mass on ground necessitates a new spaceborne concept. To address this gap, Environment Climate Change Canada (ECCC), Canadian Space Agency,...
Abstract. Local-scale variations in snow density and layering on Arctic sea ice were characterized using a combination of traditional pit SnowMicroPen (SMP) measurements. In total, 14 sites evaluated within the Canadian Archipelago Ocean both first (FYI) multi-year (MYI) ice. Sites contained multiple pits with coincident SMP profiles as well unidirectional transects. An existing model was recalibrated manual cutter measurements (n = 186) to identify best-fit parameters for observed...