Potential of RADARSAT-1 for the monitoring of river ice: Results of a case study on the Athabasca River at Fort McMurray, Canada (original) (raw)
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Monitoring the ice cover evolution of a medium size river from RADARSAT-1: preliminary results
Until the launch of RADARSAT-1, no satellite could offer sufficient spatial resolution or repeat coverage so that remote sensing could play a significant role in river ice monitoring, for small to medium size rivers. The objective of this study is therefore to evaluate this recent remote sensing technology for gathering temporal and spatially distributed information on river ice cover and river ice jams. Under this framework, thirteen RADARSAT Fine mode images were acquired over a stretch of the Saint-François river (Quebec), from November 24, 2000 to April 19, 2001 (ice free to full ice cover). A temporal analysis of the backscattering coefficients shows that open water, a thin smooth ice cover and a wet and smooth snow cover all have a similar low backscattering. However, significant variations of the radar signal are visible during a fall break-up event, during spring meltdown and under complete ice cover conditions. Furthermore, specific features such as shear walls, ice roads a...
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2000
Based on recent studies, the classification of river ice cover types from RADARSAT-1 SAR images is possible with a relatively high degree of confidence. With satellite radar ice maps, the dominant ice cover types can be identified, ice type boundaries can be observed and ice cover production processes can sometimes be monitored. The ice maps can help locate the head
The importance of RADARSAT-2 imagery in monitoring river ice cover characteristics and behaviour
2014 IEEE Geoscience and Remote Sensing Symposium, 2014
Past attempts have been made to predict ice cover characteristics and behavior along rivers, both during at freeze-up and breakup conditions; however these attempts perform with varying success and are for the most part site specific. This research introduces a geospatial modelling approach which can fulfil the task of improving the predictive power of river freeze-up and ice cover breakup events. A geospatial model clusters discretized sections of a river that have similar geomorphological (e.g. sinuosity, slope, width, etc.) and ice cover (e.g. ice thickness and type) features under certain hydraulic and meteorological conditions using a multi-variant statistical clustering technique such as the principle component analysis. These clusters can then be grouped into Geomorphic Response Units, each representing a particular set of ice cover characteristics and behavior along the river. RADARSAT-2 imagery and field sampling complement the work to help in the development of the geospatial model. The Slave River in Canada is used as a test site.
ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2016
In this study, synthetic aperture radar (SAR) data from TerraSAR-X were compared with RADARSAT-2 data to evaluate their effectiveness for river ice monitoring on the Peace River. For several years RADARSAT-2 data have been successfully used for river ice observation. However, it is important to take into account data from other satellites as they may provide solutions when it is not possible to obtain images from the preferred system (e.g., in the case of acquisition priority conflicts). In this study we compared three TerraSAR-X (X-band) and three RADARSAT-2 (C-band) datasets acquired in December 2013 on a section of the Peace River, Canada. For selected classes (open water, skim ice, juxtaposed skim ice, agglomerated skim ice, frazil run and consolidated ice) we compared backscattering values in HH and VV polarisation and performed Wishart supervised classification. Covariance matrices that were previously filtered using a refined Lee filter were used as input data for classificat...
Monitoring lake ice during spring melt using RADARSAT-2 SAR
Canadian Journal of Remote Sensing, 2010
Multipolarized RADARSAT-2 SAR imagery is used to monitor lake ice during the spring melt period. The study area is Old Crow Flats, Yukon, in the Canadian Arctic. HH and HV backscatter from lake ice is shown to have significant temporal variability and interlake diversity. Backscatter thresholds are statistically estimated to discriminate decaying lake ice from open water. A classification methodology is described that uses a HH backscatter threshold to identify initial break-up and a HV backscatter threshold for the main period of break-up. Classification accuracies are .81% (K K 5 0.189) prior to initial break-up and 66%-97% (K K 5 0.353-0.868) during break-up. This study demonstrates the potential of RADARSAT-2 imagery and, by extension, other C-band SAR satellites, to provide lake ice break-up information in support of monitoring and reporting requirements, subsequent decision-making, and scientific tasks for the Government of Canada.
Remote Sensing, 2015
The winter regime of river-ice covers in high northern latitude regions is often a determining factor in the management of water resources, conservation of aquatic ecosystems and preservation of traditional and cultural lifestyles of local peoples. As ground-based monitoring of river-ice regimes in high northern latitudes is expensive and restricted to a few locations due to limited accessibility to most places along rivers from shorelines, remote sensing techniques are a suitable approach for monitoring. This study developed a RADARSAT-2 based method to monitor the spatio-temporal variation of ice covers, as well as ice types during the freeze-up period, along the main channel of the Slave River Delta in the Northwest Territories of Canada. The spatio-temporal variation of ice covers along the river was analyzed using the backscatter-based coefficient of variation (CV) in the 2013-2014 and 2014-2015 winters. As a consequence of weather and flow conditions, the ice cover in the 2013-2014 winter had the higher variation than the 2014-2015 winter, particularly in the potential areas of flooded/cracked ice covers. The river sections near active channels (e.g., Middle Channel and Nagle Channel), Big Eddy, and Great Slave Lake also yielded higher intra-annual variation of ice cover characteristics during the winters. With the inclusion of backscatter and texture analysis from RADARSAT-2 data, four water and ice cover classes consisting of open water, thermal ice, juxtaposed ice, and consolidated ice, were discriminated in the images acquired between November and March in both the studied winters. In addition to river geomorphology and climatic conditions such as river width, sinuosity or air temperature, the fluctuation of water flows during the winter has a significant impact on the variation of
Ice Freeze-up and Break-up Detection of Shallow Lakes in Northern Alaska with Spaceborne SAR
Remote Sensing, 2015
Shallow lakes, with depths less than ca. 3.5-4 m, are a ubiquitous feature of the Arctic Alaskan Coastal Plain, covering up to 40% of the land surface. With such an extended areal coverage, lakes and their ice regimes represent an important component of the cryosphere. The duration of the ice season has major implications for the regional and local climate, as well as for the physical and biogeochemical processes of the lakes. With day and night observations in all weather conditions, synthetic aperture radar (SAR) sensors provide year-round acquisitions. Monitoring the evolution of radar backscatter (σ°) is useful for detecting the timing of the beginning and end of the ice season. Analysis of the temporal evolution of C-band σ° from Advanced Synthetic Aperture Radar (ASAR) Wide Swath and RADARSAT-2 ScanSAR, with a combined frequency of acquisitions from two to five days, was employed to evaluate the potential of SAR to detect the timing of key lake-ice events. SAR observations from 2005 to 2011 were compared to outputs of the Canadian Lake Ice Model (CLIMo). Model simulations fall within similar ranges with those of the SAR observations, with a mean difference between SAR observations and model simulations of only one day for water-clear-of-ice (WCI) from 2006 to 2010. For freeze onset (FO), larger mean differences were observed. SAR analysis shows that the mean FO date for these
Retrieval of River Ice Thickness From C-Band PolSAR Data
IEEE Transactions on Geoscience and Remote Sensing, 2014
River ice has an important effect on natural processes and human activities in northern countries. Current models for estimating river ice thickness are mostly based on environmental data. They require several inputs and yield only a global estimate of ice thickness for a large heterogeneous area. Attempts have been made intending to retrieve river ice thickness from remote sensing using monopolarized C-band radar data. No reliable maps of ice thickness have been produced. In this paper, the potential of polarimetric synthetic aperture radar (PolSAR) data for estimating river ice thickness is demonstrated, and a river ice thickness retrieval model is proposed. The C-band SAR images used in this paper were acquired by Radarsat-2 in the winter of 2009 over the Saint-François River (Southern Quebec), the Koksoak River (Northern Quebec), and the Mackenzie River (Northwest Territories) in Canada. Field campaigns were carried out to obtain ice thickness validation data at 70 locations. Polarimetric entropy was used to obtain ice thickness estimates. This approach results in spatially distributed ice thickness maps for selected ice types. Index Terms-Polarimetric synthetic aperture radar (PolSAR), river ice, thickness retrieval. I. INTRODUCTION R IVER ice has an important effect on natural processes and human activities in northern countries such as Canada. Information on river ice cover supports science, engineering, and management activities, including hydraulic modeling, ice breakup forecasting, ice road routing, infrastructure design, industrial water control, and ice hazard management. River ice cover variables of interest typically include coverage, type, thickness, and condition. In this paper, the focus is on the most challenging variable, i.e., ice thickness. Existing models for retrieving river ice thickness are mostly local estimators based on environmental data [1]-[3]. They require many inputs and provide only one global value of ice thickness for a large heterogeneous area. Synthetic aperture radar (SAR) satellite offer considerable potential in support of river ice monitoring [4]-[7]. SAR achieves relatively fine resolution and operates in the microwave range of the electromagnetic spectrum. This