Using Remotely Sensed Data to Track Sít’ Kusá (Turner Glacier) Surge Movement

Although you cannot easily tell that a glacier is moving when you see one in nature, glaciers are capable of moving at speeds of up to tens of meters per day. Some glaciers switch between periods of slow and rapid flow at regular intervals, known as surges. A glacier surge is a relatively short time period over which a glacier moves at rates 10-100 times more than what is normal for that glacier. While it is known that the processes at base of the glacier play a significant role in surging, there are still many unknowns regarding the exact triggers of surges. In an effort to better understand controls on surges, our research group has been investigating the most recent surge (2019-2021) of Turner Glacier in southeast Alaska. We have been mapping changes in glacier speed by tracking distinct features on the glacier surface that are visible in Landsat 8 and Sentinel-2 images with NASA’s autoRIFT algorithm. These images have 15-meter and 10-meter resolution (square meters per pixel), respectively, and are collected on weekly timescales. We found that the glacier is often obscured by clouds, hindering our analysis. My research focuses on pioneering the use of daily 3 meter-resolution images from PlanetScope to create velocity maps of the Turner Glacier with more detailed coverage in space and time. Here, I present the record of Turner Glacier’s surface velocities from all usable PlanetScope image pairs in 2019, prior to the start of the surge. In the future, I plan to expand the analysis to the entire surge period. Additionally, I will continue to refine this technique and apply it to other glaciers in the St. Elias Mountain Range in order to compare glacier surge timing and propagation across multiple glaciers that surged over similar time periods