Mapping the outlines of glaciers has primarily relied on the interpretation of satellite optical images. Such changes could have significant implications for hydrology, wildlife, vegetation, and subsistence hunting in rural Alaska. Climate change may be altering the distribution, elevation, melt behavior, and overall extents of the Brooks Range perennial snowfields. Results also show that perennial snowfields are more persistent at higher elevations over time with notable consistency in at least one of the Brooks Range sub-domains of this study, Gates of the Arctic National Park and Preserve. Results indicate that perennial snowfield extents in the Brooks Range are decreasing over decadal time scales, with short-lived, interannual and seasonal increases. This may be the result of synthetic aperture radar algorithm dependency on backscatter thresholding techniques and slope corrections in mountainous complex topography. The multi-spectral approach appears to perform similarly well within multiple geographic domain sizes. Evaluations of the Synthetic Aperture Radar change detection algorithm via comparison with results from optical imagery analysis, as well as via comparison with field acquired data, indicate that the radar algorithm performs best in small, focused geographic sub-domains. The logistic temperature melt model considers summer season snow cover area changes per pixel in remotely sensed products and relationships to several independent variables, including elevation-lapse-adjusted air temperature and terrain-adjusted solar radiation. Also, a snowfield melt model was developed using an adaptation of the temperature index method to determine probability of melt via binary logistic regression in two dimensions. Results of the remote sensing analyses were compared to helicopter and manually collected field data. A Synthetic Aperture Radar change detection algorithm was also developed to quantify snow cover area using Sentinel-1 data. Perennial snowfield classification techniques were developed using optical multi-spectral imagery from NASA Landsat and European Space Agency Sentinel-2 satellites. The remote sensing data are used to map and quantify snow cover area changes across multiple temporal scales, spatial resolutions, and geographic sub-domains. In this study, perennial snowfield extents in the Brooks Range are derived from satellite remote sensing, field acquired data, and snowmelt modeling. Snowfields also influence hydrology, vegetation, permafrost, and have the potential to preserve valuable archaeological artifacts. They serve as habitat for an array of wildlife, some of which are crucial for rural subsistence hunters. Perennial snowfields, such as those found in the Brooks Range of Alaska, are a critical component of the cryosphere. Such remote sensing/GIS studies, coupled with field investigations, are vital for producing baseline information on glacier changes, and improving our understanding of the complex linkages between atmospheric, lithospheric, and glaciological processes. Field and satellite investigations indicate that many small glaciers and glaciers in temperate regions are downwasting and retreating, although detailed mapping and assessment are still required to ascertain regional and global patterns of ice‐mass variations. This requires addressing numerous issues, including the generation of topographic information, anisotropic‐reflectance correction of satellite imagery, data fusion and spatial analysis, and GIS‐based modeling. The Global Land‐Ice Measurements from Space (GLIMS) project is specifically designed to produce and augment baseline information to facilitate glacier‐change studies. Predicting the human and natural dimensions of climate‐induced environmental change requires global, regional and local information about ice‐mass distribution, volumes, and fluctuations. A significant component is the Earth's cryosphere, as glacier‐related, feedback mechanisms govern atmospheric, hydrospheric and lithospheric response. Concerns over greenhouse‐gas forcing and global temperatures have initiated research into understanding climate forcing and associated Earth‐system responses.
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