03241nas a2200505 4500008004100000022001400041245010400055210006900159260001200228300001800240490000700258520177600265653001502041653001302056653001402069653001302083653001902096100002202115700001802137700001602155700002402171700002302195700002302218700001502241700002202256700001802278700002202296700002302318700002402341700002202365700001902387700002302406700001302429700002302442700002102465700002702486700002402513700002302537700001402560700002602574700002002600700003102620700001502651856006902666 2025 eng d a0043-139700aOne-hundred fundamental, open questions to integrate methodological approaches in lake ice research0 aOnehundred fundamental open questions to integrate methodologica c05/2025 ae2024WR0390420 v613 a

The rate of technological innovation within aquatic sciences outpaces the collective ability of individual scientists within the field to make appropriate use of those technologies. The process of in situ lake sampling remains the primary choice to comprehensively understand an aquatic ecosystem at local scales; however, the impact of climate change on lakes necessitates the rapid advancement of understanding and the incorporation of lakes on both landscape and global scales. Three fields driving innovation within winter limnology that we address here are autonomous real-time in situ monitoring, remote sensing, and modeling. The recent progress in low-power in situ sensing and data telemetry allows continuous tracing of under-ice processes in selected lakes as well as the development of global lake observational networks. Remote sensing offers consistent monitoring of numerous systems, allowing limnologists to ask certain questions across large scales. Models are advancing and historically come in different types (process-based or statistical data-driven), with the recent technological advancements and integration of machine learning and hybrid process-based/statistical models. Lake ice modeling enhances our understanding of lake dynamics and allows for projections under future climate warming scenarios. To encourage the merging of technological innovation within limnological research of the less-studied winter period, we have accumulated both essential details on the history and uses of contemporary sampling, remote sensing, and modeling techniques. We crafted 100 questions in the field of winter limnology that aim to facilitate the cross-pollination of intensive and extensive modes of study to broaden knowledge of the winter period.

10acryosphere10alake ice10alimnology10amodeling10aremote sensing1 aCulpepper, Joshua1 aSharma, Sapna1 aGunn, Grant1 aMagee, Madeline, R.1 aMeyer, Michael, F.1 aAnderson, Eric, J.1 aArp, Chris1 aCooley, Sarah, W.1 aDolan, Wayana1 aDugan, Hilary, A.1 aDuguay, Claude, R.1 aJones, Benjamin, M.1 aKirillin, Georgiy1 aLadwig, Robert1 aLeppäranta, Matti1 aLong, Di1 aMagnuson, John, J.1 aPavelsky, Tamlin1 aPiccolroaz, Sebastiano1 aRobertson, Dale, M.1 aSteele, Bethel, G.1 aTom, Manu1 aWeyhenmeyer, Gesa, A.1 aWoolway, Iestyn1 aXenopoulos, Marguerite, A.1 aYang, Xiao uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024WR03904202923nas a2200181 4500008004100000245015400041210006900195260004800264300000700312490000900319520225400328653002202582653001502604653002902619100002002648700002502668856004802693 2023 eng d00aCharacterizing velocity gradients in the McMurdo Dry Valleys with high-resolution optical imagery, feature-tracking methods, and in situ observations0 aCharacterizing velocity gradients in the McMurdo Dry Valleys wit aBoulder, CObUniversity of Colorado Boulder a430 vM.S.3 a

In the water-limited McMurdo Dry Valleys – the largest ice-free region of Antarctica – glaciers are the only significant source of meltwater to ephemeral streams and ecosystems. Understanding changes to the flow of these glaciers, along with characterizing how they are growing or shrinking, can elucidate how these physical controls on the region’s hydrology and ecology are responding to changing environmental conditions. Because in situ observations are difficult to collect and discrete by nature, various computer vision techniques are increasingly used to track glacier surface velocities from satellite optical and radar datasets. The most common of these techniques is image cross-correlation in the form of template matching or particle image velocimetry (PIV). Although exact methods vary, generally, cross-correlation works by co-registering temporally offset image pairs using similarity in pixel values resulting from distinctive surface features, such as crevasses, large sastrugi and snow dunes. When surface features are well-resolved with respect to an image pair’s spatial resolution, and well-preserved relative to its temporal resolution, velocity estimates can have sub-pixel precision. However, when glaciers lack meaningful surface texture – a common occurrence for the low-gradient, frozen-bed glaciers of the McMurdo Dry Valleys – cross correlation performs poorly. Using high-resolution (sub-meter per pixel) imagery can help derive texture from minor cracks and small erratics on otherwise smooth, uncrevassed surfaces, but additional adaptations are needed to improve cross correlation performance. These include additional filtering and histogram stretching steps, along with informed search area windows. Velocity estimates derived from this workflow are shown to be comparable to recorded ranges, in situ measurements, and manual feature tracking, but provide a much higher spatial and temporal resolution dataset. Alongside contemporaneous analyses of glacier mass balance, terminal thickness and surface roughness, these glacier velocity data help characterize how glaciers are dynamically evolving in response to environmental conditions in the Dry Valleys.

10across correlation10acryosphere10aglacier surface velocity1 aVanderwilt, Mia1 aGooseff, Michael, N. uhttps://www.proquest.com/docview/291637751904020nas a2200241 4500008004100000245019000041210006900231260004000300490001000340520313500350653002103485653001703506653001503523653001903538653001703557653003803574653002903612653001803641653000903659100001903668700002403687856006703711 2016 eng d00aQuantifying sources, distribution, and processing of light absorbing aerosols in the cryosphere: A comparison of dissolved and refractory black carbon in polar and high mountain regions0 aQuantifying sources distribution and processing of light absorbi aBoulder, CObUniversity of Colorado0 vPh.D.3 a

Light absorbing aerosols (LAAs) in snow and ice are one of the least understood parameters in global climate models due to complicated physical processes within the cryosphere and too few in situ observations. Ground observations are limited due to the difficulty of collecting and preserving samples for analysis from remote environments.
In order to help build a larger repository of ground observations, this dissertation explores the concentration and composition of black carbon (BC) in snow and glacial melt-water across the polar regions in the Arctic and Antarctic, as well as major mountain regions such as the Himalayas, Rockies, and Andes Mountains.

Three state-of-the-art methods for BC detection are applied in this dissertation. The first chapter identifies chemical signatures of past and present sources of dissolved black carbon (DBC) in Antarctic lakes, utilizing a DBC molecular marker method. Here we find that DBC with a woody signature is preserved in the deep, ancient brines of Antarctic lake bottom waters. In contrast, the surface waters are enriched in BC from fossil fuels. The second chapter, which also utilizes the DBC molecular marker

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technique, explores DBC across the cryosphere. We show that DBC concentrations are surprisingly high in the bottom waters of Antarctic lakes compared to other remote regions of the cryosphere, even those located near point sources. Aged snow also contains higher DBC concentrations than fresh snow suggesting that dry deposition brings the majority of BC to the cryosphere. Additionally, the DBC composition across samples from the cryosphere are similar due to high amounts of solar exposure leading to photodegradation, except in fresh snow with a wildfire signature. The third and fourth chapters utilize the Single Particle Soot Photometer to measure refractory black carbon (rBC). The third chapter also applies spectral albedo measurements and the light absorption heating method to find that coal dust from an active mine in Svalbard, Norway significantly reduces the spectral reflectance of the surrounding Arctic surface snow. The fourth chapter reports aerosol rBC concentrations in the boundary layer of the McMurdo Dry Valleys, as well as in snow from the accumulation area of the Commonwealth Glacier. Here we determine that aerosol concentrations increase during high wind events, but there is no significant trend in deposition in the snow pit. This could be due to sporadic deposition during katabatic wind events.

These findings support the importance of real in-situ observations in order to fully understand the role of BC in the global carbon cycle. It is also evident that local environmental processes can control the concentrations and composition of BC in the cryosphere. These ground-based measurements will likely serve as ground validation for future remote sensing of snow/ice impurities and LAAs deposition models.

 

10aapplied sciences10ablack carbon10acryosphere10aearth sciences10aglacial melt10ahealth and environmental sciences10alight absorbing aerosols10apolar regions10asnow1 aKhan, Alia, L.1 aMcKnight, Diane, M. uhttps://search.proquest.com/docview/1834518541?accountid=14503