Since November 2016, Ethan has been working steadily on quantifying snow dynamics throughout the Yellowhead region, and relating spring-time snow melt patterns to grizzly bear movement and behavior. The first part of his research was to develop daily 30×30 meter fractional snow covered area (fSCA) maps, which give an indication of the percentage of ground covered with snow in a given location. He combined the strengths of two leading satellite platforms, Landsat and MODIS, to create the daily dataset spanning from 2000-2017. The methods used to create the snow maps were published in August 2018 in the Journal Remote Sensing of Environment, titled ‘Daily estimates of Landsat fractional snow cover driven by MODIS and dynamic time-warping’. The article can be found online using the following URL: https://authors.elsevier.com/a/1XUUz7qzSjUkA
Figure 1: A diagram displaying the general process used to create the daily snow maps, using both MODIS and Landsat data, and an algorithm based on dynamic time warping. The spatial detail of the 30×30 meter product is highlighted on the right, compared with already existing snow cover data at 500×500 meter resolution on the left. The increase in resolution will allow Ethan to analyze grizzly bear movement and behavior on a fine scale.
With a fine-scale snow cover map in hand, Ethan is now working to answer the following questions about grizzly bear movement and behavior: In the four-week period after grizzly bear den emergence in the spring-time, are grizzly bears selecting for areas that have less snow cover? Additionally, how can fine-scale snow cover maps be used to predict where bears will be in the spring-time during the period of snow melt? By answering these questions, Ethan hopes to provide valuable insights on the relationship between bears and snow in a changing environment. With a greater understanding of how bears interact with patterns of snow melt in the spring time, land managers can better plan for future climatic conditions, and help to limit negative human-bear encounters during critical times of the year.
Video 1: A time-lapse video showcasing the new snow cover product from August 1, 2016 to July 31, 2017 in a mountainous area within the Yellowhead Region.
Berman, E. E., Bolton, D. K., Coops, N. C., Mityok, Z. K., Stenhouse, G. B., & Moore, R. D. (Dan). (2018). Daily estimates of Landsat fractional snow cover driven by MODIS and dynamic time-warping. Remote Sensing of Environment, 216(April), 635–646. https://doi.org/10.1016/J.RSE.2018.07.029