with Canadian Space Agency project: Research team using C‑band RADARSAT-2 and X-band COSMO-Skymed data to monitor landscape disturbance, change
Earth observing (EO) satellites are an apt tool for monitoring our continually-changing world. EO-derived geo-information products help researchers to investigate and understand the processes that cause and result from a given change and also to support ongoing monitoring and needed mitigation. EO products support exploration and stewardship of Earth's natural resources and ecosystems. It is against this background that LOOKNorth has undertaken a two-year project under a Canadian Space Agency (CSA) initiative, Science and Operational Applications Research (SOAR).
SOAR is a joint partnership program between the Government of Canada, through the Canadian Space Agency (CSA) and Canada Centre for Remote Sensing (CCRS), and MacDonald Dettwiler and Associates Ltd. - Geospatial Services Inc. (MDA GSI). The program provides an opportunity for Canadian researchers to explore and exploit the enhanced capabilities of MDA’s RADARSAT-2 through access to its synthetic aperture radar (SAR) data, so that Canadian stakeholders can benefit from the $450 million federal government investment in the development of this national mission.
The SAR Monitoring of Disturbances and Wetland Landscape Changes project will investigate how C‑band RADARSAT-2 and X-band COSMO-Skymed data can be used together to improve applications for identifying man-made linear disturbance, polar research, regular wetland delineation and cost-effective large-area landscape monitoring. A team of LOOKNorth researchers in collaboration with researchers from the University of Guelph are working to develop an automated procedure for detecting linear disturbances, (such as seismic lines, roads and pipelines), as well as a new object-based methodology for wetland mapping, using coherence, polarimetric and spatial information derived from SAR imagery. The team is also working to develop a new method for detecting landscape change using time-series SAR data. This will enable monitoring of hydrological processes and water quality changes over time that may result from land-based oil or waste-water spills in northern wetlands.
Right: Imagery showing linear disturbance, extracted from data from a) RADARSAT-2; b) COSMO-Skymed; c) Landsat8; d) shows the reference layer.
CSA and the Italian Space Agency (ASI) have partnered to support basic and applied research and development of algorithms, methods and applications, providing up to 40 scenes of COSMO-SkyMed and RADARSAT-2 radar satellite imagery for this project. Data has been acquired over a study area in northern Alberta known to feature linear disturbances (Figure 1). Seismic lines (3-5m wide) can be clearly observed from both X-band and C-band, providing information on narrow linear disturbances in areas of high linear density (such as road networks and repeat seismic studies), which could not previously have been obtained from optical satellite images.
Left: Seismic corridor creates linear disturbance in boreal forest
The method developed by the LOOKNorth team will help provide timely information for land-use planning, monitoring and reclamation of landscape disturbances from seismic lines, and environmental assessment, especially in remote areas; this in turn will facilitate monitoring of the cumulative effects of human-caused change on environmentally-sensitive northern and arctic areas.
An example of specific application for the new technology is in habitat reclamation. Field observations suggest that caribou do not like to cross open cut lines and become trapped between them, while wolves use open cut lines to travel quickly when hunting caribou. The multi-source data method enables timely detection of linear disturbances and facilitates monitoring of reclamation efforts to ensure disturbed caribou habitat is remediated and the animals’ migration/feeding range is restored.