CGRG Bibliography of Canadian Geomorphology
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Author : Alasset, P.; Parsons, G.; Yue, B.; Chamberland, J.; and Mulvie, J.
Date : 2009.
Title : A combination of different Synthetic Aperture Radar (SAR) techniques for bottom-fast ice and permafrost monitoring in Canadian Polar Region (Mackenzie Delta).
Publication : 2009 American Geophysical Union Fall Meeting. December 14-18, 2009. San Francisco, California, USA.
Issue :
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Abstract
The Mackenzie Delta is a unique region in the Canadian North which is rich in hydrocarbons and supports a fragile ecosystem. A need exists to define nominal remote coastal conditions prior to hydrocarbon extraction and to assist in monitoring conditions once the extraction will be underway. Near shore the formation of Bottom-Fast Ice (BFI) plays an important role in the region’s seasonal environmental changes and in the understanding of arctic coastal environmental and geophysical control processes. BFI is ice that has frozen to the seabed in shallow sea water and forms in areas where the sea water is shallow. These regions control permafrost distribution, spring overflow and potential strudel scours – holes in the frozen seafloor from flowing fresh water in rivers and streams during spring in the Beaufort Sea – and influence channel mouth constraints and early breakup season flood routing. BFI has been studied by generating D-InSAR (Differential SAR Interferometry) coherence maps during the winter of 2007-2008 and 2008-2009 using a combination of SAR image pairs from the TerraSAR-X space borne sensor. The results derived from these data were compared to results obtained from ALOS-PALSAR and RADARSAT-2 using advanced polarimetric techniques for BFI delineation. All coherence maps of the winter 2008-2009 data were assembled and compiled to demonstrate seasonal changes throughout the winter. The results of these analyses indicate that deriving coherence maps from repeat-pass data generates a product that is indicative of BFI regions; though relying on an entirely different land characteristic than polarimetric BFI delineation (e.g. ground stability vs. dielectric constants). Through the use of various polarimetric channels, a good discrimination between BFI regions and ice-covered land regions has been noted in the past. With specialised analysts, it is possible to reasonably outline BFI regions from these polarimetric datasets. Additional to these standard techniques, a coherence mapping technique provides a different view of the region that is often complimentary to that of the polarimetric techniques and that is not reliant on the saline content of the region. These techniques are not mutually exclusive since you can produce coherence map from polarimetric data. On the land regions of the Delta, generation of baseline D-InSAR digital elevation models (DEM) are a key to predicting the location of potential flooding, monitoring relative height variations, and keeping a historical record of coastal erosion. Due to the remote location, size, and continually shifting land from natural phenomena, it is difficult to get up-to-date high resolution DEMs of the Mackenzie Delta. From 2009 RADARSAT-2 UltraFine data (3m cell resolution), height elevations models have been obtained and compared to a LiDAR survey conducted in 2008.
Bibliography of Canadian Geomorphology