Network research focuses on the big questions: Where and when is permafrost thaw occurring in Canada and what are the hazards arising from such change?
The research is organized in five interwoven themes requiring a critical mass and diversity of expertise that no single research group or government agency has.
Background and objectives
Permafrost monitoring is critical to planning and decision-making in northern Canada and must provide accurate information on permafrost change at spatial and temporal scales relevant to stakeholders. This requires techniques that distinguish among annual cycles, inter-annual variation, long-term trends, and rapid anomalous changes.
Permafrost monitoring provides essential early indicators of adverse developments, informs infrastructure planning and adaptation with reliable evidence, supports national and global assessments and is necessary to evaluate the accuracy of predictive models, such as those developed in Theme 3.
The objective of Theme 2 is to use monitoring to reveal and quantify permafrost change in Canada and understand its varying rates and expressions at the land surface.
Permafrost monitoring has been carried out in northern Canada for more than 30 years by government organisations and individuals, with much of this effort focusing on two Essential Climate Variables (ECVs): permafrost thermal state and active-layer thickness. Continuing to monitor these ECVs remains vital. NSERC PermafrostNet researchers are also addressing the challenges that are emerging with rapid permafrost thaw and changing permafrost landsystems by developing monitoring practices that support responsible development and climate change assessment.
Challenge 1 – enhanced site-specific monitoring of ground temperature increase and ground-ice loss where thaw is underway is required for detecting warming trends in permafrost close to 0°C.
Challenge 2 – expand beyond site-specific observations to quantify thaw-induced change at the landscape scale to generate an increasingly accurate national picture of permafrost thaw.
The Theme will culminate with a crosscutting synthesis that draws on data and results of all the projects.
Theme 2 is jointly led by Trevor Lantz (University of Victoria) and Antoni Lewkowicz (University of Ottawa). Trevor is an expert on mapping and understanding the ecological impacts of thermokarst. He has worked extensively with northern organisations to develop community-driven environmental monitoring initiatives. Antoni is a past president of the Canadian Permafrost Association and International Permafrost Association. His research is focused on the impacts of climate change on the distribution and thermal state of permafrost. They work together to ensure that projects link with research in other themes and liaise with partners regarding research and outputs. Six researchers will be trained under Theme 2, consisting of 2 MSc, 4 PhD, 1 Post-Doctoral Fellow.
The Theme 2 researchers are remote sensing specialists as well as permafrost field and data scientists.
Bernhard Rabus provides expertise in Synthetic Aperture Radar (SAR), InSAR and optical remote sensing.
Stephan Gruber provides expertise in permafrost data science and modelling.
Our approach includes field monitoring, engagement with Indigenous groups and northern communities, remote sensing, and the synthesis of data and insight created by the diverse team. Two sub-themes address the challenges, sub-theme 2.1 measure or infer, and sub-theme 2.2: synthesis.
The objective of sub-theme 2.1 is to measure or infer permafrost change using remote sensing and traditional and local knowledge so that spatial patterns and temporal trends can be discerned. Developing corresponding monitoring tools will lead to next practices for detecting the magnitude and rate of change associated with permafrost thaw.
The objective of sub-theme 2.2 is to synthesise and reconcile results from differing modes of permafrost monitoring so that they can support local decision making as well as coherent national synthesis.
In this sub-theme we employ existing indicators and develop novel ones that can be measured across a range of spatial scales, such as permafrost temperature and terrain displacement. Network researchers build on the long-standing efforts of partners by co-locating most of our test sites at their monitoring locations. We use laboratory work to link electrical resistivity for different soil types and salinity conditions across a large range of temperatures.
To improve our capabilities to detect change at broader scales we explore novel methods of processing and analyzing remote sensing data. This work involves data from a variety of sensors and builds on change detection methods developed by network members. Co-locating these studies with ground-based projects in the network allow us to infer permafrost landscape change such as thaw subsidence, thaw slumps, catastrophic lake drainage or degrading ice-wedges using remote sensing.
We use the Landsat archive, change detection and geostatistical methods to map key landscape disturbances associated with permafrost thaw: ice wedge ponds, active layer detachments and retrogressive thaw slumps. We also employ airborne and spaceborne InSAR to detect and monitor changes in terrain elevation and focus on resolving error components by comparison with ground-based measurements of subsidence and snow cover. Locations important to our partners and with expected rapid change, for example recent fires, are prioritised for this work. To inventory surface phenomena indicative of permafrost thaw in communities we work with the Geological Survey of Canada (GSC) and Northwest Territories Geological Survey (NTGS) to implement manual and semi-automated mapping procedures. This is complemented by the development of monitoring protocols to engage northern residents and local organisations who observe changes in permafrost landscapes during their activities on the land (hunters, trappers, fishers, infrastructure inspectors and maintenance crews, Canadian Rangers, etc.).
Emma Street (T2-PhD2)
Title: Inuvialuit and Gwich’in knowledge of permafrost systems.
Supervisors: Trevor Lantz with Erika Hille, Amy Amos and Vernon Amos.
In this project Emma works with land users from Inuvialuit and Gwich’in communities in the western Arctic to document traditional knowledge of permafrost and permafrost-related change. To characterize the historical range of variation in permafrost conditions and document local observations of change or anomalous conditions. Emma will conduct semi-structured interviews with experts in communities in the Beaufort Delta region. This research will be pursued in collaboration with Inuvialuit Game Council and Gwich’in Renewable Resources Board. Emma will also work with partner organizations to access and analyze previously recorded interviews that may contain permafrost related observations. Working closely with local organizations in partner communities Emma will also develop a high-resolution mapping protocol which utilizes the best available information (Sentinel, WorldView-3, LiDAR DEMs, UAV ortho-mosaics and DEMS) to inventory permafrost hazards (lake drainage, ice-wedge ponding, slumps, landslides etc.). This work will support Bingqian Zhang’s (T3-PhD3) research on terrain type delineation by providing data to train and validate that work. This work is conducted in partnership with three communities across the western transect (Dawson City, Aklavik and Sachs Harbour). Co-developing a mapping protocol with partner communities will create lasting capacity to monitor change and result in technique of relevance across the circumpolar. Emma will also explore other methods of data collection (focus groups, participatory photography) that can be used to triangulate the perspectives that emerge from mapping and analysis interview data.
Lingcao Huang (T2-PhD3)
Title: Spatial monitoring permafrost change using Landsat.
Supervisors: Trevor Lantz with Antoni Lewkowicz and Steve Kokelj; internship with Canada Centre for Mapping and Earth Observation (Robert Fraser).
In many permafrost regions, the frequency of thaw-related disturbances is increasing so rapidly that maintaining accurate inventories presents a significant challenge. To overcome this challenge we will conduct investigations using indicators derived from the Landsat archive for mapping terrain disturbances associated with permafrost thaw and for interpreting their underlying processes in a geomorphic and climatic context. Semi-automated and manual mapping procedures will be developed for established indicators of permafrost thaw phenomena. 1) Ice wedge degradation: Lingcao will explore the potential of the Planet/Cubesat archive to detect recent ice wedge melt pond development over decadal scales. 2) Active layer detachments: Lingcao to lead the development of using Sentinel InSAR to identify active layer detachments. 3) Synthesis of the links between thaw processes and spatial patterns: Lingcao will continue his work to develop a circumpolar-scale map of thaw-slumps (and other mass wasting features).
Allison Plourde (T2-MSc1)
Title: Measuring surface displacement using winter SAR
Supervisors: Bernhard Rabus with Stephan Gruber and Peter Morse; internship with Northwest Territories Geological Survey.
SAR and InSAR are two methods of radar remote sensing that can be used to detect displacements of the ground surface. These displacements result from seasonal and long-term freezing and thawing and other processes such as fluctuating groundwater levels. Although SAR data is of higher quality in winter (due to absence of liquid water) than in summer, existing InSAR methods to measure long-term surface displacement can only make use of summer SAR data. To overcome this limitation, research exploring the impact of snow cover on the InSAR signal is required. This is important because it will improve the ability to track surface subsidence, one of the most ubiquitous impacts of permafrost thaw, more accurately over long durations. Allison will use measurement and experimental manipulation of snowpack at sites adjacent to the Inuvik-Tuktoyaktuk Highway to answer two questions: (1) Are existing physical models of the InSAR dry snow signal correct? (2) Can the snow signature in winter InSAR data be removed to enable the accurate measurement of heave from the winter refreezing of the active layer? Allison will establish field instruments to simultaneously measure snow depth change (accumulation and wind re-deposition) and active layer freezeback and assess their contributions to InSAR displacement measurements in the immediate vicinity of the instruments. Instrumentation is expected to include two ground-based sensors: one tilt logger permafrost motion sensor, one snow height sonic ranger; as well as two corner reflector (CR) targets for InSAR based displacement measurements, one CR deeply anchored as a stable reference, one CR floating on a soil surface raft and elevated to measure only displacement and not snow depth change.
Usman Iqbal (T2-PhD4)
Title: Airborne InSAR to monitor permafrost thaw near linear infrastructure.
Supervisors: Bernhard Rabus and Fabrice Calmels; internship with Government of the Northwest Territories Department of Infrastructure (GNWT-DOI).
Terrain deformation associated with permafrost thaw will increase the cost of managing linear infrastructure in the north. Repeat pass InSAR can monitor terrain displacement in permafrost environments, but at present, the coarse resolution of most InSAR is insufficient to detect changes relevant to infrastructure managers. This is because at extents appropriate for linear infrastructure, often 100–250 km, common spaceborne image swaths produce displacement gradients with a spatial resolution significantly coarser than 10 m. Furthermore, existing SAR satellites operate in orbits that pose operational challenges to monitoring of East-West trending infrastructure. Here, airborne repeat pass InSAR presents a cost-effective alternative for monitoring linear infrastructure such as roads, pipelines, and coastlines. Airborne InSAR can also resolve both vertical and horizontal displacements separately and can generate spatial strain and stress fields at scales fine enough (0.5–1 m) for infrastructure analysis. Usman will develop the processing techniques required to use airborne repeat pass InSAR for creating maps relevant to monitoring stresses on linear infrastructure caused by permafrost thaw. The most obvious products are maps of permafrost change (coherence-based and amplitude-based) and subsidence (input: InSAR phase), and maps of standing water (input: InSAR coherence and/or SAR backscatter); more elaborate products are high quality cost-effective displacement gradient (strain) maps to assess infrastructure integrity. All products can contribute to assessing the risk of damage for linear infrastructure in remote permafrost terrain related to frost heaving or thaw subsidence (linkages with projects from Theme 5: T5-PhD1, T5-PhD2, T5-MSc7).
Maps of standing water produced by this project will also be used by project T3-PhD2 in Theme 3 (together with other field and remote sensing datasets) to work toward the modeling of lowland thermokarst development. To quantify the quality of infrastructure integrity maps achievable with the airborne system Usman will compare the accuracy of displacement measured by: 1) medium resolution spaceborne InSAR, 2) high resolution spaceborne InSAR, and 3) repeat pass airborne InSAR data. Usman will also test and optimize different motion compensation algorithms. The work is being conducted in partnership with Yukon Government Transportation Engineering Branch along the Alcan Highway and in collaboration with other potential end-users such as GNWT-DOI. Test segments will be selected in collaboration with network partners to create synergy with preexisting test sites and with documented permafrost-related infrastructure problems. Usman will be involved in planning and executing two spring and fall airborne campaigns of airborne sensor SlimSAR based out of Kluane-Silvercity. Campaigns will result in acquisition of suitable (two-directional) InSAR data sets acquired along the Alcan Highway. Synergies with T5-PhD1 (Risk management of linear infrastructure in remote permafrost terrain) may open up as the projects develop.
In Sub-theme 2.2 (synthesis) we combine and reconcile results of the diverse monitoring approaches so that they can support decision making at local to national scales. This sub-theme includes three projects that focus on national-scale synthesis, developing new methods to synthesise thermal and surface subsidence data from boreholes across Canada.
This research is critical because existing methods for interpreting ground temperature data largely rely on sensors at single depths and do not account for landscape-scale variation. Under the lead of Theme 1, we will work with a range of stakeholders to design and pilot a standardised protocol that will allow observers across the study domain to submit observations of permafrost conditions and work with our partners at Canadian Consortium for Arctic Data Interoperability (CCADI) to pilot an online interface to make summary data and results from Themes 2, 3 and 4 available to partners and the public. These efforts are particularly important because identifying anomalous landscape changes in a timely manner requires local and traditional knowledge.
Title: Interpreting ground temperature and subsidence for better quantifying permafrost change.
Supervisors: Stephan Gruber with Kumari Karunaratne and Derek Mueller.
Permafrost temperature is a key metric of permafrost change, but existing methods for its quantitative interpretation mostly report on sensors at single depths. Furthermore, latent heat consumption when thawing permafrost perturbs the ground temperature signal. Given that, it can be difficult to detect changes in permafrost based on trends in ground temperature time series of a single depth. Moreover, strong lateral landscape-scale variation of temperature is often invisible in analyses that only use a small subset of Canada’s data.
Using PINGO (Theme 1), this project aims to develop and automate new methods for characterizing spatio-temporal variation in ground temperature and detect trends. In doing so, Fereshteh will analyse all thermal data available in Canada as well as co-located time series of surface movement to investigate where and when is permafrost thaw occurring and what spatial patterns exist in Canada. Any sign in the profile which can be attributed to the loss of ground ice will be complemented with trends of annual temperature ranges at different depths, providing insight on the thermal effects of ground-ice loss. Further, to assess the performance of the developed method, detected thaw induced changes in the profile will be tested using simulated data based on GEOtop and FreeThaw1D.
Multisite analysis will employ statistical models for separating pattern related to site characteristics and climate in order to better understand the drivers of observed changes. In a final step, Fereshteh will develop and improve products that are suitable for communicating results on permafrost change to non-expert audiences and will provide key methods and insight towards prototype climate services and synthesis reporting based on the monitoring of permafrost temperature and surface subsidence that may result in recommendations for future monitoring strategies.
Pete Castillo (T2-MSc2)
Title: Towards a Permafrost Observation Platform.
Supervisors: Trevor Lantz with Pascale Roy-Léveillée and Erika Hille.
Niek Jesse Speetjens (T2-PDF1)
Title: Synthesizing observations to develop a responsive monitoring network.
Supervisors: Trevor Lantz and Stephan Gruber
Collaborators and partners
- E. Hille
- S.V. Kokelj
- F. Calmels
- P. Lipovsky
- V. Amos
- A. Amos
- S.L. Smith
- P. Morse
- R. Fraser
Peer-reviewed research findings are listed on our Publications page.