Estimating Bedrock Fracture Density Of The Juneau Icefield, Ak, To Inform Glacial Erosion Models,
2020
University of Maine
Estimating Bedrock Fracture Density Of The Juneau Icefield, Ak, To Inform Glacial Erosion Models, Colby Rand
Honors College
Understanding glacial erosion rates is important because debris eroded by a glacier can impact glacier flow speeds, protect tidewater glaciers from rapid retreat, and impact the productivity of marine ecosystems. Traditionally, glacial erosion models rely on a rock’s inherent “erodibility”, typically presented as a constant, to predict how much debris will be eroded by the glacier. However, the erodibility of bedrock varies spatially as a function of its fracture density, fracture orientation, and lithology, so the notion of applying a constant erodibility term to a whole field site does not fully capture the actual bedrock dynamics of the system. In …
Climate From The Mcmurdo Dry Valleys, Antarctica, 1986–2017: Surface Air Temperature Trends And Redefined Summer Season,
2020
Cascades Volcano Observatory, U.S. Geological Survey
Climate From The Mcmurdo Dry Valleys, Antarctica, 1986–2017: Surface Air Temperature Trends And Redefined Summer Season, Maciej K. Obryk, Peter T. Doran, Andrew G. Fountain, M. Myers, Christopher P. Mckay
Geology Faculty Publications and Presentations
The weather of the McMurdo Dry Valleys, Antarctica, the largest ice‐free region of the Antarctica, has been continuously monitored since 1985 with currently 14 operational meteorological stations distributed throughout the valleys. Because climate is based on a 30‐year record of weather, this is the first study to truly define the contemporary climate of the McMurdo Dry Valleys. Mean air temperature and solar radiation based on all stations were −20°C and 102 Wm−2, respectively. Depending on the site location, the mean annual air temperatures on the valleys floors ranged between −15°C and −30°C, and mean annual solar radiation varied …
Applications Of Digital Remote Sensing To Quantify Glacier Change In Glacier And Mount Rainier National Parks,
2020
Stephen F. Austin State University
Applications Of Digital Remote Sensing To Quantify Glacier Change In Glacier And Mount Rainier National Parks, Brianna Clark
Electronic Theses and Dissertations
Digital remote sensing and geographic information systems were employed in performing area and volume calculations on glacial landscapes. Characteristics of glaciers from two geographic regions, the Intermountain Region (between the Rocky Mountain and Cascade Ranges) and the Pacific Northwest, were estimated for the years 1985, 2000, and 2015. Glacier National Park was studied for the Intermountain Region whereas Mount Rainier National Park was representative of the glaciers in the Pacific Northwest. Within the thirty year period of the study, the glaciers in Glacier National Park decreased in area by 27.5 percent while those on Mount Rainier only decreased by 5.7 …
The Microstructural Heterogeneity Of Ice In Jarvis Glacier, Alaska,
2020
University of Maine
The Microstructural Heterogeneity Of Ice In Jarvis Glacier, Alaska, Renée Clavette
Honors College
Glacier ice behaves as a viscous fluid, where flow is controlled by a number of external and internal processes. One crucial, yet sometimes overlooked, factor is ice microstructure. Studies have shown that ice crystal (grain) size, shape, and orientation influence the viscous strength of ice, and therefore its resistance to flow and deformation. Glacier flow is also impacted by friction at the bed and lateral margins. The magnitude of flow resistance due to the lateral margins is not well quantified. The goal of this overall project is to evaluate how heterogeneous optical properties of ice are that are influenced by …
La Relación Entre Cambio Climático Y Migración En Los Andes De Perú: Los Q’Ero, Taquile Y La Cordillera Blanca,
2020
SIT Study Abroad
La Relación Entre Cambio Climático Y Migración En Los Andes De Perú: Los Q’Ero, Taquile Y La Cordillera Blanca, Sam Hosmer-Quint
Independent Study Project (ISP) Collection
El cambio climático es uno de los problemas más grandes en el mundo. Los afectos de los cambios serán más graves para las personas más pobres y vulnerables. Perú es reconocido como uno de los países más vulnerables en el mundo, a causa de la presencia de glaciares tropicales, las cual son muy vulnerables a la desglaciación. Los efectos de cambio climático incluyen, entre otras cosas; el cambio de la temporada de lluvias y sequias, un aumento de la temperatura ambiental, inundaciones y tormentas severas. Todos estos factores hacen del cambio climático un riesgo para mucha gente y además, tiene …
Climate Change Effects On Volcanoes In The Tropics: A Review Of The Deglaciation Of Antisana And Its Effects On Subsequent Water Streams And Rivers Over 20 Years,
2020
SIT Study Abroad
Climate Change Effects On Volcanoes In The Tropics: A Review Of The Deglaciation Of Antisana And Its Effects On Subsequent Water Streams And Rivers Over 20 Years, Callie C. Rominger
Independent Study Project (ISP) Collection
Located in the Northern end of Ecuador lies the stunning glacier of Antisana which attracts many tourists and whose runoff provides a significant amount of water supply for Quito. Climate change is posing threats to many ecosystems world wide but will have a more substantial impact on the volcanoes in the tropics because they do not have a seasonally altered climate. Small changes in the air temperature can have larger impacts on these areas that are adapted to constant temperatures with seasonal precipitation changes. Climate change, in recent years, had caused an increase in the glacial retreat of the Antisana …
Modeling The Pleistocene History Of The Greenland Ice Sheet,
2020
University of Massachusetts Amherst
Modeling The Pleistocene History Of The Greenland Ice Sheet, Benjamin Andrew Keisling
Doctoral Dissertations
One of the most profound and immediate consequences of anthropogenic climate change is sea level rise, which in large part is driven by the melting of polar ice sheets. The Greenland Ice Sheet (GrIS) contains enough ice to raise global sea level by ~7 meters. Fluctuations of the GrIS in response to past climate change provide an opportunity to better understanding the stability of the ice sheet during periods of climatic change. In this thesis, we use numerical ice-sheet models to understand the causes and consequences of past fluctuations of the Greenland ice sheet. In Chapters 3 and 4, we …
Twentieth Century Black Carbon And Dust Deposition On South Cascade Glacier, Washington State, Usa, As Reconstructed From A 158‐M‐Long Ice Core,
2020
Central Washington University
Twentieth Century Black Carbon And Dust Deposition On South Cascade Glacier, Washington State, Usa, As Reconstructed From A 158‐M‐Long Ice Core, Susan D. Kaspari, Dan Pittenger, T. M. Jenk, U. Morgenstern, M. Schwikowski, N. Buenning, L. Stott
All Faculty Scholarship for the College of the Sciences
Light absorbing particles (LAPs) include black carbon (BC) and mineral dust and are of interest due to their positive radiative forcing and contribution to albedo reductions and snow and glacier melt. This study documents historic BC and dust deposition as well as their effect on albedo on South Cascade Glacier (SCG) in Washington State (USA) through the analysis of a 158‐m (139.5‐m water equivalent [w.e.]) ice core extracted in 1994 and spanning the period 1840–1991. Peak BC deposition occurred between 1940 and 1960, when median BC concentrations were 16 times higher than background, likely dominated by domestic coal and forest …
Future Evolution Of Greenland's Marine-Terminating Outlet Glaciers,
2020
University of Texas at Austin
Future Evolution Of Greenland's Marine-Terminating Outlet Glaciers, G. A. Catania, L. A. Stearns, T. A. Moon, E. M. Enderlin, R. H. Jackson
Geosciences Faculty Publications and Presentations
Mass loss from the Greenland ice sheet (GrIS) has increased over the last two decades in response to changes in global climate, motivating the scientific community to question how the GrIS will contribute to sea-level rise on timescales that are relevant to coastal communities. Observations also indicate that the impact of a melting GrIS extends beyond sea-level rise, including changes to ocean properties and circulation, nutrient and sediment cycling, and ecosystem function. Unfortunately, despite the rapid growth of interest in GrIS mass loss and its impacts, we still lack the ability to confidently predict the rate of future mass loss …
Esd Ideas: Why Are Glaciations Slower Than Deglaciations?,
2020
CUNY Graduate Center
Esd Ideas: Why Are Glaciations Slower Than Deglaciations?, Christine J. Ramadhin, Chuixiang Yi
Publications and Research
The Earth’s climate during the Quaternary is dominated by short warm interglacials and longer cold glaciations paced by external forcings such as changes in insolation. Although not observed in the solar radiation changes, the time series of the cycles display asymmetry since transitions to full glacial conditions are slower than the termination of glaciations. Here an idea is proposed for the slower transition by identifying and describing two negative sea ice feedbacks dominant during the glaciation process that could serve as a control on the intermediate stage and decrease the pace of the process.
Glacial Earthquakes And Precursory Seismicity Associated With Thwaites Glacier Calving,
2020
Central Washington University
Glacial Earthquakes And Precursory Seismicity Associated With Thwaites Glacier Calving, J. Paul Winberry, Audrey D. Huerta, Sridhar Anandakrishnan, Richhard C. Aster, Andrew A. Nyblade, Douglas A. Wiens
All Faculty Scholarship for the College of the Sciences
We observe two (~MS 3) long‐period (10–30 s) seismic events that originate from the terminus of Thwaites Glacier, Antarctica. Serendipitous acquisition of satellite images confirm that the seismic events were glacial earthquakes generated during the capsizing of icebergs. The glacial earthquakes were preceded by 6 days of discrete high‐frequency seismic events that can be observed at distances exceeding 250 km. The high‐frequency seismicity displays an increasing rate of occurrence, culminating in several hours of sustained tremor coeval with the long‐period events. A series of satellite images collected during this precursory time period show that the high‐frequency events and …
Chronology Of Advance And Recession Dynamics Of The Southern Green Bay Lobe Of The Laurentide Ice Sheet,
South-Central Wisconsin, Usa,
2020
University of Wisconsin-Madison
Chronology Of Advance And Recession Dynamics Of The Southern Green Bay Lobe Of The Laurentide Ice Sheet, South-Central Wisconsin, Usa, Eric C. Carson, John W. Attig, J. Elmo Rawling Iii, Paul R. Hanson, Stefanie E. Dodge
School of Natural Resources: Faculty Publications
We used a combination of accelerator mass spectrometry (AMS) radiocarbon dating, optically stimulated luminescence (OSL) age estimates, and stratigraphic data from cores collected along the southern margin of the Green Bay Lobe (GBL) of the Laurentide Ice Sheet to provide new information on the timing and dynamics of the end of advance of the GBL and the dynamics of the ice sheet while very near its maximum position. Coring at multiple sites along the margin of the GBL indicate that ice had reached a stable position near its maximum extent by 24.7 ka; that ice advanced several kilometers to the …
Geochemical Flux Analysis Of Glacial River Runoff For Sólheimajökull, Iceland,
2020
Western Kentucky University
Geochemical Flux Analysis Of Glacial River Runoff For Sólheimajökull, Iceland, Jessica Garrison
Mahurin Honors College Capstone Experience/Thesis Projects
Geochemical fluxes in aqueous studies are an essential component of research to understand weathering and changes in a hydrologic system. These data can indicate any discrepancies, outliers, or gradual changes in a water environment to gain information on pollutants, carbon cycles, biological input, etc. Glacial melt is the majority of the surface water present throughout the country. The melting amount is increasing with the temperatures, which can be monitored by the changes in geochemical flux during increased discharge in glacial rivers. A high-resolution data set of Sόlheimajökull Glacier in Iceland was used to determine how changing climatic conditions for the …
Rock Glacier Development In The San Juan Mountains,
2020
University of Denver
Rock Glacier Development In The San Juan Mountains, Brandon K. Bailey
Electronic Theses and Dissertations
Rock glaciers are common landform features found in deglaciated alpine areas. They are commonly used in the study of climatic changes throughout the Holocene and the reconstruction of neoglacial chronologies. For this research, Schmidt hammer rebound values, weathering rind thicknesses, and the length of lichen thalli diameters found on rock glacier surfaces are used to investigate their effectiveness as field-based relative age determination techniques. Additionally, the ability to identify periods of neoglacial activity using these methods is assessed in two neighboring cirque basins in the San Juan Mountains of Colorado. 41 field sites across three rock glaciers are established with …
The Seasonal Evolution Of Albedo Across Glaciers And The Surrounding Landscape Of Taylor Valley, Antarctica,
2020
University of Colorado, Boulder
The Seasonal Evolution Of Albedo Across Glaciers And The Surrounding Landscape Of Taylor Valley, Antarctica, Anna Bergstrom, Michael N. Gooseff, Peter T. Doran, Julian M. Cross
Geology Faculty Publications and Presentations
The McMurdo Dry Valleys (MDVs) of Antarctica are a polar desert ecosystem consisting of alpine glaciers, ice-covered lakes, streams, and expanses of vegetation-free rocky soil. Because average summer temperatures are close to 0 Cel., the MDV ecosystem in general, and glacier melt dynamics in particular, are both closely linked to the energy balance. A slight increase in incoming radiation or change in albedo can have large effects on the timing and volume of meltwater. However, the seasonal evolution or spatial variability of albedo in the valleys has yet to fully characterized. In this study, we aim to understand the drivers …
Sampling The Local Fare: Fishes At The Sam Israel House Pit (45gr76), Soap Lake, Washington,
2020
Central Washington University
Sampling The Local Fare: Fishes At The Sam Israel House Pit (45gr76), Soap Lake, Washington, Adam Fruge
All Master's Theses
The Sam Israel site is a precontact archaeological complex with numerous fish bones at the north end of Soap Lake, Washington. Excavated in 1976, the fish remains recovered from there were never fully analyzed prior to this research. Since this inland Columbia Plateau site had thousands of fish bones, it contained untapped potential for our understanding of ancient local fish procurement. As such, I conducted a detailed analysis of 2,862 fish bone specimens from the Sam Israel House Pit locus to: study a larger sample of fish bones in greater detail than was done before; compare the distribution of fishes …
Climate And Surging Of Donjek Glacier, Yukon, Canada,
2020
Boise State University
Climate And Surging Of Donjek Glacier, Yukon, Canada, Ellyn M. Enderlin
Geosciences Faculty Publications and Presentations
Links between climate and glacier surges are poorly understood but are required to enable prediction of surges and mitigation of associated hazards. Here, we investigate the role of snow accumulation, rain, and temperature on surge periodicity, area changes, and timing of surge initiation since the 1930s at Donjek Glacier, Yukon, Canada. Snow accumulation measured in three ice cores collected at Eclipse Icefield indicates that a cumulative accumulation of 15.5 ± 1.46 or 16.6 ± 2.0 m w.e. occurred in the ten to twelve years between each of its last eight surges, depending on ice motion spatiotemporal offset corrections. Although we …
Improving Aquifer Characterization Through Integration Of Airborne Electromagnetics (Aem) And Well Hydrographs,
2019
University of Nebraska - Lincoln
Improving Aquifer Characterization Through Integration Of Airborne Electromagnetics (Aem) And Well Hydrographs, Jacqueline Polashek
School of Natural Resources: Dissertations, Theses, and Student Research
The objective of this study is to evaluate methods of hydrostratigraphic modeling using geophysics and well hydrographs at the eastern edge of the High Plains aquifer (HPA) in Platte and Colfax counties within Nebraska, USA. The HPA is very heterogeneous in the study area, being hosted by architecturally complex glacial sediments and having many irregular hydraulic boundaries. Further, the HPA exhibits local variations between unconfined and confined conditions. Pumping in such bounded aquifers can be unsustainable because of cost increases and lost agricultural productivity. Moreover, the large drawdowns typical of confined aquifers can contribute to well interference during heavy pumping. …
An Evaluation Of Soils On Sólheimajökull Glacier Foreland: Using Invertebrates And Decomposition As Bio-Indicators Of Soil Quality,
2019
SIT Study Abroad
An Evaluation Of Soils On Sólheimajökull Glacier Foreland: Using Invertebrates And Decomposition As Bio-Indicators Of Soil Quality, Carolyn Weisman
Independent Study Project (ISP) Collection
Anthropogenic climate change has led to the retreat of glaciers globally. As glaciers melt, they expose the underlying land- termed the glacier foreland. These forelands provide a natural laboratory for studying ecological succession after a massive disturbance, which is in this case glaciation. In this study, soil invertebrates and decomposition are used as bio-indicators of the soil quality in the foreland of Sólheimajökull Outlet Glacier. Soil cores were collected from five sites (A-E) located 300m apart moving away from the glacier terminus. The abundance of each observed invertebrate taxa and the dissolved oxygen (DO) levels were taken for 30 soil …
A Collection Of On-Ice Arctic Measurements 1879-2013,
2019
JPL
A Collection Of On-Ice Arctic Measurements 1879-2013, Ryan Avila
STAR Program Research Presentations
Ice thickness measurements have been taken in the arctic through a variety of means for a long time in order to better understand the long-term changes to sea ice. This project is focused on measurements made directly on the ice by using an auger or electromagnetic sounding which have both been shown to be highly accurate compared to other observational methods. Our first goal is to create and update an archive of sea ice data that collects smaller separated data sets in one easy to access location for other researchers to use. Our second goal is to use this data …
