Nouvelles

Victor Pozsgay will be presenting A model of temperature inversions to correct bias in reanalysis data.

Date: 14 May 2025
Time: 13:00-14:00 Eastern Time
Location: Zoom (details are posted in our Teams site).

The magnitude and frequency of slope failures in permafrost zones have increased in recent decades. Permafrost warming and thawing represent major contributing factors to large slope failures, which have the potential to damage infrastructure and pose a risk to human life and surrounding ecosystems. 

I will present a simulation workflow to generate ensemble simulations of the ground thermal regime at any point globally. The model is driven by reanalysis data, which are known to poorly represent temperature inversions. Hence, I will focus on modelling temperature inversions in sub-arctic valleys where cold-air pooling is particularly intense in cold months. This framework allows for consistent and efficient production and analysis of mountain permafrost simulations in relation to slope failures. However, its main strength and appeal lie in its ability to be used globally and for a large number of sites, efficiently. 

Zhina Rezvani will be presenting Assessing Thaw Settlement Vulnerability of the Hudson Bay Railway in the Face of Climate Change.

Date: 23 April 2025
Time: 13:00-14:00 Eastern Time
Location: Zoom (details are posted in our Teams site).

The effects of climate change are intensified in northern regions due to polar amplification. As a result, the stability and functionality of infrastructure in these areas are under greater threat than ever before. The Hudson Bay Railway (HBR), located in northern Manitoba, is a prime example of vulnerable infrastructure facing the challenges of a warming climate.

In this webinar, Zhina Rezvani will share insights into assessing the impacts of climate change on permafrost thaw, which leads to soil settlement beneath the railway embankment. Her research involves finite element thermal modeling followed by coupled thermo-mechanical modeling to simulate both the current and projected future conditions of the soil and permafrost under the railway embankment and adjacent area. The findings of this study will support HBR policymakers in making informed, strategic decisions regarding the future of the railway, whether through improvement methods, mitigation measures, or potential realignment of certain sections.

Emma Street will be presenting Exploring Traditional Knowledge of Permafrost Change in the Gwich’in Settlement Area and Inuvialuit Settlement Region.

Date: 16 April 2025
Time: 13:00-14:00 Eastern Time
Location: Zoom (details are posted in our Teams site).

Rapid climate change at high latitudes is transforming permafrost landscapes: threatening infrastructure, ecosystems, and socio-cultural traditions in Arctic communities. This project seeks to better understand the implications of permafrost change in Gwich’in and Inuvialuit communities in the Canadian Arctic. Using semi-structured interviews and ethnographic mapping in collaboration with knowledge holders, the goals of this project are to (1) document Traditional Knowledge pertaining to permafrost, (2) map evidence of permafrost change in Gwich’in and Inuvialuit communities, and (3) inform responsive monitoring programs. 110 interviews have been completed for this project among the eight communities of Paulatuk, Sachs Harbour, Tuktoyaktuk, Ulukhaktok, Fort McPherson, Tsiigehtchic, Aklavik, and Inuvik. This presentation describes the Two-Eyed Seeing and community-driven participatory research.

Olivia Meier-Legault will be presenting How can we learn more about permafrost thaw in Canada from borehole temperature observations?

Date: Wednesday 7 May
Time: 13:00-14:00 Eastern Time
Location: Zoom (details are posted in our Teams site).

Mean annual ground temperature (MAGT) is widely used as a key indicator of permafrost change and has long informed climate assessments. However, in the presence of melting ice, latent heat effects can dampen temperature trends, making interpretation difficult. To address this limitation, complementary metrics derived from simulations resembling borehole temperature observations have been developed and tested to show their ability to provide new information on heat gain in the permafrost column.

In this seminar, Olivia will present the application of five of these metrics on borehole temperature observations. The metrics are (1) MAGT, (2) mean annual ground surface temperature, (3) top of permafrost, (4) depth of zero annual amplitude, and (5) the thermal integral. She will cover how these metrics maximize the use of available data and improve our understanding of permafrost thaw in Canada.

Hosein Fereydooni will be presenting Ground Ice Detection with Spectral Induced Polarization.

Date: 2 April 2025
Time: 13:00-14:00 Eastern Time
Location: Zoom (details are posted in our Teams site).

The melting of ground ice poses significant hazards in permafrost regions, leading to ground instability, infrastructure damage, and environmental changes. Detecting ground ice effectively is crucial for mitigating these risks, yet conventional geophysical methods—such as electrical resistivity, seismic surveys, and ground-penetrating radar—often produce ambiguous results due to the overlapping properties of frozen and unfrozen ground.

This presentation will explore the potential of Spectral Induced Polarization (SIP) as a more precise method for identifying ground ice. It will begin by discussing the theoretical foundations and mathematical principles of SIP, followed by an examination of various polarization mechanisms, with a focus on those specific to frozen environments, and an explanation of relaxation time. The study will then present field measurement results from a permafrost site in Yukon, demonstrating SIP’s ability to detect and distinguish ground ice in real-world conditions.

Galina Jonat will be presenting Improving predictions of permafrost conditions by using data from climate models that centres the impacts of permafrost thaw.

Date: 5 March 2025
Time: 13:00-14:00 Eastern Time
Location: Zoom (details are posted in our Teams site).

Permafrost predictions rely on models that simulate how the ground responds to changes in climate. These predictions are of limited use for local studies as climate model data does not capture small-scale variations and contains uncertainties and biases. While bias correction can improve how well the climate data matches local climate dynamics, these improvements do not always lead to improvements in the predictions of permafrost change produced by permafrost models.

In this seminar, Galina will introduce a new way to select bias-corrected climate model data based on how well it represents permafrost conditions. She will use examples from two sites near Inuvik to show how this approach can help reduce uncertainty and improve predictions about how permafrost will change over time.

Danielle Chiasson will be presenting Post-Drainage Evolution of Wolverine Lake, Old Crow Flats, Yukon.

Date: 12 February 2025
Time: 13:00-14:00 Eastern Time
Location: Zoom (details are posted in our Teams site).

This presentation explores the post-drainage evolution of vegetation succession and basin morphology of a large lake that drained in Old Crow Flats prior to anthropogenic climate warming. Old Crow Flats is a large permafrost lowland undergoing rapid landscape change related to catastrophic lake drainage events and landscape-scale shrubification. While post-drainage conditions have been well documented in modern lake basins, little is known about the evolution from young basins to old. Danielle will present the results from her radiocarbon dated macrofossil analyses of the margin and centre of a drained lake basin. By reconstructing the history of vegetation succession and its associated permafrost conditions better comparisons can be made of past and present basin evolution.