SEALS ON ICE: DEVELOPING AN IMAGE CLASSIFICATION WORKFLOW TO PRODUCE THEMATIC MAPS OF ICE CALVING INTO SEVERAL TIDEWATER GLACIERS FJORDS IN KENAI FJORDS NATIONAL PARK

Glaciers in Alaska are melting rapidly, changing environmental conditions and necessitating a higher frequency of monitoring to maintain an understanding of current conditions for informed natural resource management. We developed an image classification workflow that processes large amounts of monitoring data to map icebergs from imagery using ArcGIS segmentation tools. Icebergs are used as habitat by seals in Alaska fjords. Existing methods used to record icebergs and seals generate large volumes of photos that require digitization of icebergs. Using normalized difference indices and pixel brightness characteristics, we implemented an automated object-based segmentation method that allows scientists to efficiently process large quantities of remotely collected image data to map changing seal habitat. In 2023, we conducted repeat aerial photo surveys using a belly-mounted camera in a fixed-wing aircraft in Kenai Fjords National Park, Alaska. Overlapping photos were acquired at 4,200 ft above ground level and used to produce individual 15 cm resolution imagery mosaics of three tidewater glaciers and their fjords for each month throughout the harbor seal phenological period. We developed an automated mapping technique using ArcGIS Pro and Jupyter Notebook to produce thematic maps of subaerial ice from the imagery mosaics. Furthermore, we describe the mapping technique using variables, making this process applicable to any project that collects imagery with the goal of generating ice estimates for multiple acquisitions. Our 2023 results indicate decreasing areas and counts of icebergs as the summer progressed (e.g., 13,536 to 343 bergs in Aialik Bay from May to August). Results of our classification show the effectiveness of using normalized band indices to accentuate differences in ice/water and pixel brightness to refine preliminary outputs. Future revisions to the workflow could focus on error assessment and reduction. The notebook demonstrates how programmatic implementation can leverage geoprocessing tools, inline annotations, and scripting to simplify data management, test classification methods, and strengthen science communication. We highlight the utility of our notebook to produce a sharable analytical workflow product allowing for interagency collaboration, repeated processing for future acquisitions, and organized data outputs.