A5071466248- Cryospheric studies and observations
- Climate change and permafrost
- Arctic and Antarctic ice dynamics
- Soil Moisture and Remote Sensing
- Winter Sports Injuries and Performance
- Meteorological Phenomena and Simulations
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Precipitation Measurement and Analysis
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Microwave-Assisted Synthesis and Applications
- Landslides and related hazards
- Climate variability and models
- Ecology and Vegetation Dynamics Studies
- Avian ecology and behavior
- Aerospace Engineering and Energy Systems
- Smart Materials for Construction
- Species Distribution and Climate Change
- Soil and Unsaturated Flow
- Icing and De-icing Technologies
- Superconducting and THz Device Technology
Environment and Climate Change Canada
2013-2024
University of Guelph
2017
Wilfrid Laurier University
2017
University of Waterloo
2008
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)...
A synthetic study was performed to determine the potential retrieve dry-snow density and ground permittivity from multiangular L-band brightness temperatures. The thereto employed emission model developed parts of "microwave layered snowpacks" (MEMLS) coupled with components adopted "L-band microwave biosphere" (L-MEB) model. restriction made it possible avoid scattering absorption in snow volume, leading a rather simple formulation our Parametric studies revealed signatures related mass...
Two unique observational data sets are used to evaluate the ability of multi-layer snow emission models simulate passive microwave brightness temperatures (TB) in high latitude, observation sparse, snow-covered environments. Data were utilized from a coordinated series 18 sites measured across subarctic Northwest Territories and Nunavut, Canada April 2007 during 1000 km segment 4200 km snowmobile traverse Fairbanks, Alaska Baker Lake, Nunavut (~64°N). In 2011, network 22 Arctic was sampled...
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...
Abstract Identifying and understanding why traits make species vulnerable to changing climatic conditions remain central problems in evolutionary applied ecology. We used spring snow cover duration as a proxy for phenological timing of wetland ecosystems, examined how during the entire season affected population dynamics duck breeding western boreal forest N orth A merica, 1973–2007. predicted that level responses would differ among species, such late‐nesting with reduced flexibility their...
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...
Two-dimensional measurements of snowpack properties (stratigraphic layering, density, grain size, and temperature) were used as inputs to the multilayer Helsinki University Technology (HUT) microwave emission model at a centimeter-scale horizontal resolution, across 4.5 m transect ground-based passive radiometer footprints near Churchill, Manitoba, Canada.Snowpack stratigraphy was complex (between six eight layers) with only three layers extending continuously throughout length...
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...
Abstract. Accurate simulations of snow emission in surface-sensitive microwave channels are needed to separate from atmospheric information essential for numerical weather prediction. Measurements a field campaign Trail Valley Creek, Inuvik, Canada during March 2018 were used evaluate the Snow Microwave Radiative Transfer (SMRT) Model at 89 GHz and, first time, frequencies between 118 and 243 GHz. In situ data 29 pits, including specific surface area, calculate exponential correlation...
The seasonal snowpack across the boreal forest is an important national resource in both Canada and Finland, contributing freshwater for agriculture, human consumption, hydropower generation. In countries, satellite passive microwave data are utilized to provide operational information on snow depth water equivalent (SWE) throughout cover season. Airborne surveys conducted independently Finland western during March April 2005 2006 provided opportunity assess level of similarity physical...
Abstract The extent, timing and duration of seasonal freeze/thaw (FT) state exerts dominant control on boreal forest carbon, water energy cycle processes. Recent on-going L-Band (≈1.4 GHz) spaceborne missions have the potential to provide enhanced information FT over large geographic regions with rapid revisit time. However, low spatial resolution these observations (≈45 km) makes it difficult isolate primary contributions (soil, vegetation, snow) signal in forest. To better quantify...
Abstract Tundra snow cover is important to monitor as it influences local, regional, and global‐scale surface water balance, energy fluxes, well ecosystem permafrost dynamics. Observations are already showing a decrease in spring duration at high latitudes, but the impact of changing winter season temperature precipitation on variables such equivalent (SWE) less clear. A multi‐year project was initiated 2004 with objective quantify tundra properties over multiple years scale appropriate for...
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...
Passive microwave measurements from space are known to be sensitive the freeze/thaw (F/T) state of land surface. These at a coarse spatial resolution (~15–50 km) and variability emissions within pixel can have important effects on interpretation signal. An L-band ground-based radiometer campaign was conducted in Canadian Prairies during winter 2014–2015 examine surface frozen thawed periods. Seven different sites Kenaston soil monitoring network were sampled five times between October 2014...
The observed brightness temperatures (Tb) at 37 GHz from typical moderate density dry snow in mid-latitudes decreases with increasing water equivalent (SWE) due to volume scattering of the ground emissions by overlying snow. At a certain point, however, as SWE increases, emission snowpack offsets sub-nivean emission. In tundra snow, Tb slope reversal occurs shallower thicknesses. While it has been postulated that inflection point seasonal time series V is controlled formation thick wind slab...
Detailed angular ground-based L-band brightness temperature (TB) measurements over snow covered frozen soil in a prairie environment were used to parameterize and evaluate an electromagnetic model, the Wave Approach for LOw-frequency MIcrowave emission Snow (WALOMIS), seasonal snow. WALOMIS, initially developed Antarctic applications, was extended with interface model. A Gaussian noise on layer thickness implemented account natural variability thus improve TB simulations compared...
Abstract Several large in-situ soil moisture-monitoring networks currently exist over seasonally frozen regions that may have use for the validation of remote sensing freeze/thaw (F/T) products. However, further understanding how existing network instrumentation responds to changes in near surface F/T is recommended. This case study describes results a small plot-scale (7 × 7 m) from November 2013 through April 2014 instrumented with 36 impedance probes. Soil temperature and real dielectric...