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Ontario Provincial Flood Forecasting and Warning workshop
Operational Monitoring of River Ice Break-up Conditions using RADARSAT-2. A. Deschamps, J. van der Sanden, G. Choma, J.S. Proulx-Bourque, G. Marquis Ontario Provincial Flood Forecasting and Warning workshop Vaughan, Ontario September 15, 2015
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Outline Emergency Geomatics Service (EGS)
Brief history - river ice monitoring at Natural Resources Canada Basic concept of RADARSAT-2 applied to river ice breakup monitoring Examples from 2015 Pilot Study Future Work
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Since 2006, the Emergency Geomatics Service (EGS) supports emergency response activities in Canada by producing GIS-ready satellite-derived information products to a large community of emergency responders (federal & provincial) Primarily support flood events 2015 Pilot Study, use RADARSAT-2 derived ice condition information during breakup season Products provide near-real time situational awareness to assist emergency authorities with public safety and critical infrastructure risk
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How is EGS Activated? (24/7) (24/7) (24/7) Provincial
EMO Public Safety Canada, Gov. Operations Centre (GOC) (24/7) NRCan Dept. Emergency Operations Center (DEOC) (24/7) NRCan/ESS Canadian Hazard Information Service (CHIS) (24/7) This is how we have been activated in past DND (DART) CCMEO Emergency Geomatics Service (EGS) (International) Note: Specific needs and the technical feasibility of requests are assessed on a case by case basis by the EGS team in collaboration with PS and partners.
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Radar Remote Sensing of River Ice - NRCAN
Pilot Project for 3 rivers in Northern Ontario. +“response” products for additional rivers in ON and NB. At the request of Public Safety Canada (PS), EGS provided ice breakup products in demonstration mode for responses in ON and MB. Continue on with a second year of pilot project to improve products and services. Research on River Ice Breakup monitoring using R2 based on IPY funding to Dr. Van der Sanden at CCRS. 2013 2014 2015 2016 Development of IceBC tool at the request of Ontario MNRF. IP development and released to the province of Ontario in 2013. EGS continues to improve the automation of the IceBC tool. Science to Ops Transition R&D Operations Geomatic Support
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2015 Pilot Study –RADARSAT for River Ice Breakup Monitoring
Conducted a Pilot Project in collaboration with Public Safety Canada and the Ontario Ministry of Natural Resources – Surface Water Monitoring Centre. Goal: Demonstrate the benefit of RADARSAT-2 for operational monitoring of river ice-breakup on 3 rivers in Northern Ontario. Moose River Albany River Attawapiskat River
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Ice Jams – A Costly Hazard
The impact of ice covered rivers on Canadians typically peaks at the time of breakup; in particular, when ice jams form and cause flood and/or damage to nearby infrastructure. The annual direct costs of ice jamming and associated flooding in Canada estimated at $60 million, indirect costs can be much higher. (Gerard and Davar, 1995) Photo Credit Embâcle sur le fleuve Saint-Jean à Perth-Andover Crédit photo : Étienne Dumont/Radio-Canada Fort-Albany Flood Watch Other ideas: Cost reference for Kash: hhttp:// Cost reference for St.Lawrence: Morse, B., and Hicks, F., 2005, Advances in river ice hydrology, 1999–2003: Hydrological Processes, v. 19, no. 1, p. 247– Fort Albany, ON (May 10, 2014) Perth-Andover, NB (April 19, 2015) Photo Credit: Fort-Albany Flood Watch Photo Credit: Étienne Dumont/Radio-Canada
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Radar Remote Sensing of River Ice
Satellite derived products provide a synoptic overview of ice breakup areas: Can provide early warnings of problem. Can help focus on areas of concern. Best used in conjunction with ground and air surveys. RADARSAT offers much potential as tool for collecting information about river ice condition. This can be explained from: its weather and daylight independent imaging capability, sensitivity to the presence of water, sensitivity to surface roughness, capability to penetrate frozen (dry) ice cover, sensitivity to structural features within the ice volume The backscatter of wet spring ice is governed by the surface roughness
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Radar Remote Sensing of River Ice
Frozen (dry) winter ice and melting (wet) spring ice interact with radar waves in a distinctly different fashion! Ice Breakup Classification (IceBC) algorithm exploits the sensitivity of SAR to differences in the roughness of breaking (wet) river ice cover. The backscatter of wet spring ice is governed by the surface roughness
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IceBC for Breakup Monitoring - Workflow
Post-processing: classification filtering, applying Land mask and map Generation. Product validation IceBC – Ice Classification (Standalone Executable) Pre-processing: image ‘calibration’, speckle filtering, and orthorectification/mosaic, extract incidence angle. Radarsat-2 Image + DEM Mask applied to ice cover condition classification product KMZ Ice cover condition information product Ice cover condition classification Land/water mask, generated from NHN/Landsat FULLY AUTOMATED!
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IceBC for Breakup Monitoring - Workflow
Based on Python code + Matlab exe Software: PCI Geomatica Global Mapper (KMZ) Inputs: RADARSAT-2 image (C-band SAR, HH-Polarization) NOTE: Public Safety Canada can provide access to satellite imagery for Emergency Management purposes. Water mask (NHN 1:5000) DEM mosaic (CDED 1:50000) Outputs: Ice breakup classification in TIF and KMZ format. Selecting images with larger incidence angles (>36°) Tool Ingests selected beam modes (Fine, Standard, Wide, EH, Ultra-Fine and Wide Ultra-Fine)
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IceBC - Products Products discriminate between ‘water’ and three classes each for ice cover conditions identified as ‘sheet ice’ or ‘rubble ice’. Sheet ice covers are characterized by smooth textures whereas rubble ice covers have rough textures. Ice jams are a form of rubble ice with rough to very rough textures (shown in red & fushia) => Validated by field or repeat observations Repeat observations or field validation is needed to determine if an ice cover that exhibits the texture of an ice jam is indeed jammed Sheet Ice Cover (smooth) Rubble Ice Cover (rough)
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Pilot Study: Validated Ice Jam on Moose River (ON) - April 23, 2015
Ground validation photo provided by Ontario MRNF
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Pilot Study: Ice Condition on Moose River (ON) - April 30, 2015
Ground validation photo provided by Ontario MRNF
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Operational Ice Breakup Monitoring - Challenges
Transition from dry winter ice vs. wet spring ice affect the type of SAR scattering. Compile weather, streamflow, snow cover, optical images R2 temporal signature & breakup onset Diurnal effects are prevalent in early breakup phase Cycle of freeze-thaw cycles prevalent in Southern Canada High winds (>6 m s-1) and rapids increases the roughness of water and complicates the discrimination of the open water and sheet ice classes. Wet snow on ice or standing water on ice can be expected to be misclassified as water. Dynamic ice condition at breakup complicates validation The IceBC algorithm was developed to work with melting / wet ice conditions that are usually present in the spring breakup season. Application of the method to SAR images acquired during winter / dry ice conditions will produce results that are not in line with the legend that accompanies the products. Current Solution: Monitor temperature, streamflow, Modis/Landsat, snow cover in conjunction with and SAR backsatter behaviour over time to determine onset of breakup and start of product delivery. (See example in next slides…)
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Stage 1: High backscatter in winter
March 26, 2015 (F1 morning pass) For illustration only (Fort McMurray) Polygon #2 is at white crosshair! Determining the onset of breakup using Radarsat-2 temporal signature (assumes acquisition with suffcient frequency). Stage 1: You start with a high backscatter in winter (dry ice and snow cover; volume scattering) Stage 2: The backscatter drops when the snow starts to melt in early spring (wet snow/water on top of ice cover; surface scattering) Stage 3: The backscatter increases following snow melt (bare wet ice, surface scattering) Stage 4: Start of breakup IceBC outputs are only reliable in the stages 3 and 4 of the breakup process
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Stage 3: The backscatter decreases following snow melt
April 02, 2015 (W3 morning pass) For illustration only (Fort McMurray) Polygon #2 is at white crosshair! Determining the onset of breakup using Radarsat-2 temporal signature (assumes acquisition with suffcient frequency). Stage 1: You start with a high backscatter in winter (dry ice and snow cover; volume scattering) Stage 2: The backscatter drops when the snow starts to melt in early spring (wet snow/water on top of ice cover; surface scattering) Stage 3: The backscatter increases following snow melt (bare wet ice, surface scattering) Stage 4: Start of breakup IceBC outputs are only reliable in the stages 3 and 4 of the breakup process
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Stage 3: The backscatter drops when the snow starts to melt
April 19, 2015 (F1 morning pass) For illustration only (Fort McMurray) For illustration only (Fort McMurray) Polygon #2 is at white crosshair! Determining the onset of breakup using Radarsat-2 temporal signature (assumes acquisition with suffcient frequency). Stage 1: You start with a high backscatter in winter (dry ice and snow cover; volume scattering) Stage 2: The backscatter drops when the snow starts to melt in early spring (wet snow/water on top of ice cover; surface scattering) Stage 3: The backscatter increases following snow melt (bare wet ice, surface scattering) Stage 4: Start of breakup IceBC outputs are only reliable in the stages 3 and 4 of the breakup process
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Stage 4: Breakup April 26, 2015 (W3 morning pass)
For illustration only (Fort McMurray) Polygon #2 is at white crosshair! Determining the onset of breakup using Radarsat-2 temporal signature (assumes acquisition with suffcient frequency). Stage 1: You start with a high backscatter in winter (dry ice and snow cover; volume scattering) Stage 2: The backscatter drops when the snow starts to melt in early spring (wet snow/water on top of ice cover; surface scattering) Stage 3: The backscatter increases following snow melt (bare wet ice, surface scattering) Stage 4: Start of breakup IceBC outputs are only reliable in the stages 3 and 4 of the breakup process
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Future – Research Work Integration of Sentinel-1 images in EGS workflows Transition algorithms from Radarsat-2 based operational service to the RADARSAT Constellation Mission (RCM) Diverse polarizations typically yields more information to help with target discrimination (i.e. wet/dry ice) More frequent revisits (daily) Standard coverages Investigate the utility of Synthetic Aperture Radar (SAR) for river ice freeze-up monitoring Improve robustness of flood algorithms and initiate research for flood mitigation Including urban flood & flooded vegetation Phase information from Compact Polarimetry (CP) to identify the transition from winter ice (dry – volume scattering) and spring breakup ice (wet – surface scattering). RH/RV or HH/VV to improve ice mapping in difficult cases (e.g. high wind condition, steep incidence angles). Standard Coverages: -Operational monitoring of wide area -Simplify the planning phase and eliminate conflicts. -Facilitate change detection approaches (i.e. damage assessment)
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RADARSAT Program Evolution
2018: RCM First operational civilian SAR satellite Important R&D component GoC owned Ops extended to DND, DFO, NRCan, and EC Numerous sci & ops modes MDA owned (PPP) Fully operational Selected R2, Compact Pol. Coherent Change Detection Enhanced ship detection GoC owned Fast tasking, fast delivery Source: Canadian Space Agency
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River Ice Breakup Pilot Study Phase II for 2016
Future – Operations River Ice Breakup Pilot Study Phase II for 2016 Continue to improve the River Ice Breakup (IceBC) tools to facilitate internal operations. Tools can be shared with our partners via agreements. Continue to enable our partners to use SAR derived ice condition information during ice breakup season beyond response.
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Thank You! Questions? Emergency Geomatics Service (EGS):
Director: Yvan Désy Project Manager: Geneviève Marquis Acting Operational Lead: Alice Deschamps CCRS SAR and Ice Expert: Joost Van Der Sanden EGS Team: Vincent Decker, George Choma, Pierre Gravel, JS Proulx-Bourque, Brigitte Belzil, Roger Bouchard, Charles Papasodoro
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