Brooks Range Perennial Snowfields: Extent Detection from the Field and via Satellite
Abstract. Perennial snowfields are a critical part of the alpine ecosystem, serving as habitat for an array of wildlife species, and influencing downslope hydrology, vegetation, geology, and permafrost. In this study, perennial snowfield extents in the Brooks Range of Arctic Alaska are derived from Synthetic Aperture Radar (SAR) and multi-spectral satellite remote sensing via the Sentinel-1 (S1) and Sentinel-2 (S2) constellations. Snow cover area (SCA) is mapped using multi-spectral analysis in S2 and via the creation of a SAR backscatter change detection algorithm with S1. Results of the remote sensing techniques are evaluated by comparison with field data acquired across multiple spatial resolutions and geographic domains, including helicopter points and manual, on the-ground collected SCA. Evaluations of the SAR change detection algorithm via comparison with results from multi-spectral imagery analysis, and field acquired data, indicate that the SAR algorithm performs best in small, focused geographic sub-domains. This may be the result of SAR algorithm dependency on thresholding and slope corrections in mountainous terrain. An alternative approach to mapping the perennial snowfields is also presented, as a synthesis of the S1 and S2 results, wherein S1 results are used to fill voids left in the S2 data from cloud masking processes.
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