@thesis {5025,
	title = {The temporal and spatial dynamics of surface sediment on the permanently frozen lakes of Taylor Valley, Antarctica},
	volume = {M.S.},
	year = {2025},
	month = {05/2025},
	school = {University of Wisconsin-Madison},
	type = {Master{\textquoteright}s thesis},
	address = {Madison, WI},
	abstract = {<p>The McMurdo Dry Valleys are the largest unglaciated region of Antarctica and are home to some of the only perennially frozen lakes in the world. The ice covers of the Taylor Valley lakes are subject to decadal-length fluctuations in thickness, largely ranging between three and five meters thick. It has been hypothesized that the changes in ice cover thickness are due to a combination of climate factors and lake ice surface characteristics, but as of yet there have been no studies focusing on interannual dynamics of lake ice albedo by leveraging remote sensing datasets. Landsat 8 imagery was manipulated using spectral mixture analysis to find the abundance of sediment cover across three different Taylor Valley lakes from 2016-2024 during the sunlit period of the year. Peak sediment coverage was not synchronous across years, with Lake Hoare peaking the earliest in 2021, followed by East Lake Bonney and Lake Fryxell in 2023. West Lake Bonney had no apparent peak, although concentrations have declined since 2021. Overall sediment abundance values across all lakes ranged from near 0\% to over 75\%, though each lake has a different level of sediment coverage. Lake Fryxell and Lake Hoare had the highest mean sediment concentrations, followed by East Lake Bonney, then West Lake Bonney. The relationship between ice thickness and sediment coverage was strongest at Lake Fryxell, followed by East Lake Bonney. Lake Hoare and West Lake Bonney appear to have weaker links between ice thickness and surface sediment, likely driven by differences in overall sediment cover and shading from the surrounding landscape. Ice surface albedo is a historically understudied component of ice physical structure and thermal mechanics and should be more closely considered in future studies predicting ice thickness in the McMurdo Dry Valleys, especially in cases to predict total ice loss. Permanently frozen lakes exhibit unique ice dynamics compared to seasonally freezing lakes, due to their consistent lake ice, where previous years ice conditions have a large effect on ice into the future. The McMurdo Dry Valleys (MDVs), a large unglaciated region in Antarctica, contain many of the few permanently frozen lakes that exist globally. Albedo is a critical factor influencing lake ice mass balance and may strongly govern lake ice thickness. Changes in surface albedo on MDVs lakes occur as a result of aeolian sediment deposition from the surrounding bare soil landscape or physical changes in ice quality throughout the summer, like ice whitening. To investigate the importance of surface characteristics of Taylor Valley lake ice, a one-dimensional thermal diffusion model was developed using in situ meteorological data and a satellite derived ice albedo estimates to simulate ice thickness on East Lake Bonney, Antarctica. Ice thickness was modeled from late 2016 through 2024 using a novel ice albedo dataset, derived from Landsat 8 imagery using linear spectral mixture analysis. Estimated albedo values ranged from 0.5-0.85, covering years when sediment cover was very heavy to very low. Modeled ice thickness was strongly correlated with measured thicknesses. For the period of the year where manual ice thickness measurements are made, modeled ice thicknesses ranged between 2.92-4.16 m, where measured values for that same time span ranged between 3.06-4.19 m. When either increasing or decreasing albedo by 5-10\%, mean ice thicknesses diverged by up to 0.8 m. Ice thicknesses are strongly influenced by surface sediment concentrations, and the contribution of a tailored albedo dataset was a valuable input that has historically been over-simplified.</p>},
	keywords = {LTER-MCM, aeolian geomorphology, McMurdo Dry Valleys, permanently frozen lakes, polar lakes, remote sensing},
	url = {http://digital.library.wisc.edu/1793/95194},
	author = {Dougherty, Charles E.},
	editor = {Hilary A. Dugan}
}
@phdthesis {4097,
	title = {Geophysics, Water Balance, and History of Thick Perennial Ice Covers on Antarctic Lakes},
	volume = {Ph.D.},
	year = {2014},
	school = {University of Illinois},
	type = {doctoral},
	address = {Chicago, IL},
	abstract = {<p>Antarctic lakes are studied as sentinels of future change, for paleolimnological records contained in the sediments, and as habitats for the simple food webs that can exist in inhospitable environments. Understanding how lakes are formed and are sustained in response to landscape and climate conditions is critical in addressing the aforementioned research themes. This thesis is governed by the overarching hypothesis that an understanding of hydrologic and sediment transport processes associated with lake ice formation and preservation can be used to reveal past climatic changes, and further our awareness of current changes in climate and water balance in the McMurdo Dry Valleys of Antarctica. The first chapter focuses on water loss from closed basin lakes in Taylor Valley, Antarctica, and presents updated estimates of sublimation and ablation rates from long-term empirical measurements. The second and third chapters address the formation of Lake Vida, Antarctica. The former investigates the accretion of a 27 m ice cover, and considers the origin of thick sediment layers in the ice cover, and the latter uses two geophysical methods to quantify the extent and volume of the brine network in the subsurface beneath the lake. The results presented herein advance the study of hydrogeology in continuous permafrost, provide additional evidence for fluctuating climate states in the McMurdo Dry Valleys throughout the mid to late Holocene, and provide a case study for the preservation of water in a cold, desert environment analogous to neighboring planets.</p>},
	keywords = {LTER-MCM, Antarctica, brine, lake ice, McMurdo Dry Valleys, polar lakes, sublimation},
	url = {http://hdl.handle.net/10027/19407},
	author = {Hilary A. Dugan},
	editor = {Peter T. Doran}
}
