Making sea ice thickness maps in the Canadian Arctic operationally available – Isolde Glissenaar
Sea ice thickness is a key variable when characterising an ice cover and its impact on the local environment and provides important insight into how an ice cover is changing in response to climate change. Unfortunately, observations of ice thickness are sparse, especially in the channels in the Canadian Arctic Archipelago. Sea ice thickness is also an important factor in assessing the safety of shipping in Arctic regions. The Canadian Arctic Archipelago is bisected by the Northwest Passage and is home to many northern communities that rely on marine traffic for resupply. Understanding the changes in ice thickness within the Canadian Arctic Archipelago and monitoring it in the future is therefore of vital importance.
The JGI funded my seed corn project to make sea ice thickness maps in the Canadian Arctic operationally available on a website. The ice thickness maps are created with a machine learning model that uses ice charts (maps of sea ice) from the Canadian Ice Service to estimate sea ice thickness. The ice charts have information about the sea ice concentration, the age of the ice, and the size of the separate ice floes. These characteristics all relate to sea ice thickness and can thus be used to create a proxy for sea ice thickness.
After comparing multiple machine learning methods, a Random Forest Regression model was found to give the best results. For my PhD, I applied this method on the archive of ice charts to determine sea ice thickness for the historic period 1996-2020. However, ice charts continue to be released every week, and this gave the possibility to run the model straight after a new ice chart is released and publish the resulting sea ice thickness map.
In this project I have automized the workflow so that a new sea ice thickness map is created as soon as an ice chart is released. This operational sea ice thickness map is subsequently made available online within 12 hours after the release of the ice chart. A beta-version of the website with both the operational ice thickness maps and the archive of sea ice thickness is now available on https://canadian-sit.streamlit.app/ for shipping navigators, local communities, and climate researchers to use.
Currently, the sea ice thickness maps can only be created for the winter months November-April. Future work would include extending the methods to the summer months when there is more shipping activity. The work can also be extended to the seas around Greenland, as the Danish Meteorological Institute creates similar ice charts for these regions.
For this project I collaborated with the Canadian Ice Service who create the ice charts and are responsible for communicating ice conditions with stakeholders in the region. If the method proves effective and the website reliable, the Ice Service could consider including the sea ice thickness maps in their advice to stakeholders.