Photogrammetric measurements of snow depth made from manned-aircraft within the Arctic National Wildlife Refuge, Alaska, from 2015-2020
Abstract
We made over 30 billion measurements of snow depth within the Arctic National Wildlife Refuge from 2015-2020 using photogrammetric methods from a manned aircraft as part of an effort to build a long-term snow depth climatology to support scientific and environmental protection studies. Towards this end we have been mapping two large watersheds for mountain snow-packs since 2015 and mapping tundra snow-packs since 2019. Our prior research has shown that these airborne methods are just as accurate as ground-based probing measurements, on the centimeter-decimeter level. The method works by first mapping the terrain in summer when it is snow free, then subtracting this digital elevation model (DEM) from one made in winter when it is snow covered, leaving snow depth as the primary difference given the general lack of standing vegetation here. We mapped over 6000 km2 area of tundra here in summer, so we can measure snow depth at any location of interest within it in the future, measuring over 2000 km2 of snow in 2019 and 2020, using numerous transects up to 160 km x 3 km as well several large blocks up to ~600 km2 in size, and our mountainous snow-pack coverage is typically ~500 km2 each winter in two watersheds. Image ground sample distances are typically 12.5 cm to 25 cm, with DEM postings double that. Patterns of snow depth on the tundra are substantially more heterogeneous than the majority of Arctic Alaska to the west, due largely to more complicated geology and wind patterns. The massive scale of the areas mapped give us new opportunities to improve modeling at the process and landscape levels. In addition to helping close the water balance in these Arctic watersheds, our tundra measurements also aid in understanding polar bear denning habitats and aid in regulatory planning and approval for overland-vehicle trafficability related to responsible development projects.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMC047.0003N
- Keywords:
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- 0736 Snow;
- CRYOSPHERE;
- 0740 Snowmelt;
- CRYOSPHERE;
- 0742 Avalanches;
- CRYOSPHERE;
- 1863 Snow and ice;
- HYDROLOGY