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Master of Science (MS)
Khan, Alia L.
Bunn, Andrew Godard
Wallin, David O.
The stability of our cryosphere relies on highly reflective snow surfaces that reflect solar radiation, thereby maintaining the energy balance of the earth. The advances in Uncrewed Aerial Vehicle (UAV) technology allow for researchers to assess snow surfaces in remote terrain at unprecedented scales. With this thesis, we demonstrate the range of UAV applications to assess glacier ablation and map snow algae in the North Cascades. The first chapter employs a low-cost, light-weight UAV to measure ablation of the Sholes Glacier using Structure-from-Motion technology and validates the measurements with outlet stream discharge data collected by the Nooksack Indian Tribe. We spectrally classified the orthomosaics to reveal that the glacier transitioned from 75% snow-covered to 43% snow-covered from August 17, 2021 to September 5, 2021. Digital Elevation Model differencing reveals that the glacier lost an average thickness of −0.132 m per day (m d−1) and contributed a total of 550,161 ± 45,206 m3 water equivalent whereas the stream gauge station measured a total discharge of 350,023 m3. The second chapter utilizes a high-end, multispectral UAV to map snow algae within the Bagley Lakes basin using two different spectral approaches, under two distinct bloom conditions, and calculates the radiative forcing (RF) of the snow algae. This chapter found that the success of the classification approaches depends heavily on the snow algae bloom intensity. We calculated the RF of the snow algae and found an average instantaneous RF (IRF) of 158.8 W m-2 with a maximum IRF of 360.0 W m-2. Extrapolating the IRF over the mapped snow algae extent and scaled linearly over the 29 days between the surveys, we calculate that snow algae contribute a total of 1,508 m3 of snowmelt in the 0.1 km2 basin. These results demonstrate the potential to map snow algae and assess the RF over expansive areas of the cryosphere using UAV technology.
UAV, drone, snow algae, cryosphere, glacier, snow, radiative forcing, melt
Western Washington University
Subject – LCSH
Drone aircraft in remote sensing--North Cascades (B.C. and Wash.); Glacial erosion--North Cascades (B.C. and Wash.); Algae--North Cascades (B.C. and Wash.); Radiative forcing--North Cascades (B.C. and Wash.)
North Cascades (B.C. and Wash.)
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Healy, Shannon, "UAV remote sensing approaches to mapping glacier ablation and snow algae radiative forcing in the North Cascades." (2022). WWU Graduate School Collection. 1078.