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2018

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Full-Text Articles in Glaciology

Remote Sensing Of Icebergs In Greenland's Fjords And Coastal Waters, Jessica Scheick Dec 2018

Remote Sensing Of Icebergs In Greenland's Fjords And Coastal Waters, Jessica Scheick

Electronic Theses and Dissertations

Increases in ocean water temperature are implicated in driving recent accelerated rates of mass loss from the Greenland Ice Sheet. Icebergs provide a key tool for gaining insight into ice-ocean interactions and until recently have been relatively understudied. Here we develop several methods that exploit icebergs visible in optical satellite imagery to provide insight on the ice--ocean environment and explore how iceberg datasets can be used to examine the physics of iceberg decay and parent glacier properties. First, a semi-automated algorithm, which includes a machine learning-based cloud mask, is applied to six years (2000-2002 and 2013-2015) of the Landsat archive …


Climate Evolution Across The Mid-Brunhes Transition, Aaron M. Barth, Peter U. Clark, Nicholas S. Bill, Feng He, Nicklas G. Pisias Dec 2018

Climate Evolution Across The Mid-Brunhes Transition, Aaron M. Barth, Peter U. Clark, Nicholas S. Bill, Feng He, Nicklas G. Pisias

School of Earth & Environment Faculty Scholarship

The Mid-Brunhes Transition (MBT) began ∼ 430 ka with an increase in the amplitude of the 100 kyr climate cycles of the past 800 000 years. The MBT has been identified in ice-core records, which indicate interglaciations became warmer with higher atmospheric CO2 levels after the MBT, and benthic oxygen isotope (δ18O) records, which suggest that post-MBT interglaciations had higher sea levels and warmer temperatures than pre-MBT interglaciations. It remains unclear, however, whether the MBT was a globally synchronous phenomenon that included other components of the climate system. Here, we further characterize changes in the climate system across the MBT …


Assessing Ground Penetrating Radar’S Ability To Image Subsurface Characteristics Of Icy Debris Fans In Alaska And New Zealand, Robert W. Jacob, Jeffrey M. Trop, R. Craig Kochel Dec 2018

Assessing Ground Penetrating Radar’S Ability To Image Subsurface Characteristics Of Icy Debris Fans In Alaska And New Zealand, Robert W. Jacob, Jeffrey M. Trop, R. Craig Kochel

Faculty Journal Articles

Icy debris fans have recently been described as fan shaped depositional landforms associated with (or formed during) deglaciation, however, the subsurface characteristics remain essentially undocumented. We used ground penetrating radar (GPR) to non-invasively investigate the subsurface characteristics of icy debris fans (IDFs) at McCarthy Glacier, Alaska, USA and at La Perouse Glacier, South Island of New Zealand. IDFs are largely unexplored paraglacial landforms in deglaciating alpine regions at the mouths of bedrock catchments between valley glaciers and icecaps. IDFs receive deposits of mainly ice and minor lithic material through different mass-flow processes, chiefly ice avalanche and to a lesser extent …


Alpine Ice Evidence Of A Three-Fold Increase In Atmospheric Iodine Deposition Since 1950 In Europe Due To Increasing Oceanic Emissions, Michel Legrand, Joseph R. Mcconnell, Susanne Preunkert, Monica M. Arienzo, Nathan Chellman, Kelly E. Gleason, Tomás Sherwen, Mat J. Evans, Lucy J. Carpenter Nov 2018

Alpine Ice Evidence Of A Three-Fold Increase In Atmospheric Iodine Deposition Since 1950 In Europe Due To Increasing Oceanic Emissions, Michel Legrand, Joseph R. Mcconnell, Susanne Preunkert, Monica M. Arienzo, Nathan Chellman, Kelly E. Gleason, Tomás Sherwen, Mat J. Evans, Lucy J. Carpenter

Environmental Science and Management Faculty Publications and Presentations

Iodine is an important nutrient and a significant sink of tropospheric ozone, a climate-forcing gas and air pollutant. Ozone interacts with seawater iodide, leading to volatile inorganic iodine release that likely represents the largest source of atmospheric iodine. Increasing ozone concentrations since the preindustrial period imply that iodine chemistry and its associated ozone destruction is now substantially more active. However, the lack of historical observations of ozone and iodine means that such estimates rely primarily on model calculations. Here we use seasonally resolved records from an Alpine ice core to investigate 20th century changes in atmospheric iodine. After carefully considering …


Contrasting Patterns In Surface Ice Velocity Of Glaciers In The Nepal Himalayas, Katherine Strattman Oct 2018

Contrasting Patterns In Surface Ice Velocity Of Glaciers In The Nepal Himalayas, Katherine Strattman

Von Braun Symposium Student Posters

No abstract provided.


A Sub-Millennial Sediment Record Of Ice-Stream Retreat And Meltwater Storage In The Baltic Ice Lake During The Bølling-Allerød Interstadial, April Lynn Kelly, Sandra Passchier Oct 2018

A Sub-Millennial Sediment Record Of Ice-Stream Retreat And Meltwater Storage In The Baltic Ice Lake During The Bølling-Allerød Interstadial, April Lynn Kelly, Sandra Passchier

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The rapid retreat of the Baltic Ice Stream and the development of the Baltic Ice Lake is assessed using data from sediment cores retrieved from three sub-basins in the southern Baltic Sea. Hydraulic piston coring by the International Ocean Discovery Program (IODP) recovered for the first time intact glacial lake sequences overlying diamictons and other ice-contact deposits at Sites M0063, M0064 and M0065. Based on the particle size and bulk sediment chemical composition the glacial lake sediments were subdivided into a proximal and a distal varve sequence. The origin of a dark, lithologically distinct horizon between the proximal and distal …


The 2015 Landslide And Tsunami In Taan Fiord, Alaska, Bretwood Higman, Breanyn Macinnes, Colin Bloom Sep 2018

The 2015 Landslide And Tsunami In Taan Fiord, Alaska, Bretwood Higman, Breanyn Macinnes, Colin Bloom

All Faculty Scholarship for the College of the Sciences

Glacial retreat in recent decades has exposed unstable slopes and allowed deep water to extend beneath some of those slopes. Slope failure at the terminus of Tyndall Glacier on 17 October 2015 sent 180 million tons of rock into Taan Fiord, Alaska. The resulting tsunami reached elevations as high as 193 m, one of the highest tsunami runups ever documented worldwide. Precursory deformation began decades before failure, and the event left a distinct sedimentary record, showing that geologic evidence can help understand past occurrences of similar events, and might provide forewarning. The event was detected within hours through automated seismological …


Decadal Topographic Change In The Mcmurdo Dry Valleys Of Antarctica: Thermokarst Subsidence, Glacier Thinning, And Transfer Of Water Storage From The Cryosphere To The Hydrosphere, J. S. Levy, Andrew G. Fountain, M. K. Obryk, J. Telling, Craig Glennie, M. Gooseff, David J. Van Horn Sep 2018

Decadal Topographic Change In The Mcmurdo Dry Valleys Of Antarctica: Thermokarst Subsidence, Glacier Thinning, And Transfer Of Water Storage From The Cryosphere To The Hydrosphere, J. S. Levy, Andrew G. Fountain, M. K. Obryk, J. Telling, Craig Glennie, M. Gooseff, David J. Van Horn

Geology Faculty Publications and Presentations

Recent local-scale observations of glaciers, streams, and soil surfaces in the McMurdo Dry Valleys of Antarctica (MDV) have documented evidence for rapid ice loss, glacial thinning, and ground surface subsidence associated with melting of ground ice. To evaluate the extent,magnitude, and location of decadal-scale landscape change in the MDV, we collected airborne lidar elevation data in 2014–2015 and compared these data to a 2001–2002 airborne lidar campaign. This regional assessment of elevation change spans the recent acceleration of warming and melting observed by long-term meteorological and ecosystem response experiments, allowing us to assess the response of MDV surfaces to warming …


Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data, Rajashree Datta Sep 2018

Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data, Rajashree Datta

Dissertations, Theses, and Capstone Projects

Surface melting over the Antarctic Peninsula (AP) plays a crucial role for the stability of ice shelves and dynamics of grounded ice, hence modulating the mass balance in a region of the world which is particularly sensitive to increasing surface temperatures. Understanding the processes that drive melting using surface energy and mass balance models is fundamental to improving estimates of current and future surface melting and associated sea level rise through ice-shelf collapse. This is even more important in view of the specific challenges presented by how circulation patterns over the topographically-complex Antarctic Peninsula, especially foehn winds, impact surface melt. …


The Periglacial Landscape Of Mars: Insight Into The 'Decameter-Scale Rimmed Depressions' In Utopia Planitia, Arya Bina Aug 2018

The Periglacial Landscape Of Mars: Insight Into The 'Decameter-Scale Rimmed Depressions' In Utopia Planitia, Arya Bina

Electronic Thesis and Dissertation Repository

Currently, Mars appears to be in a ‘frozen’ and ‘dry’ state, with the clear majority of the planet’s surface maintaining year-round sub-zero temperatures. However, the discovery of features consistent with landforms found in periglacial environments on Earth, suggests a climate history for Mars that may have involved freeze and thaw cycles. Such landforms include hummocky, polygonised, scalloped, and pitted terrains, as well as ice-rich deposits and gullies, along the mid- to high-latitude bands, typically with no lower than 20o N/S. The detection of near-surface and surface ice via the Phoenix lander, excavation of ice via recent impact cratering activity as …


Rock Glaciers Of The Contiguous United States: Spatial Distribution, Cryospheric Context, And Riparian Vegetation, Gunnar Forrest Johnson Aug 2018

Rock Glaciers Of The Contiguous United States: Spatial Distribution, Cryospheric Context, And Riparian Vegetation, Gunnar Forrest Johnson

Dissertations and Theses

Continental-scale inventories of glaciers are available, but no analogous rock glacier inventories exist. We present the Portland State University Rock Glacier Inventory (n = 10,343) for the contiguous United States, then compare it to an existing inventory of contiguous United States glaciers (n = 853), identifying geographic and climatic factors affecting the spatial distributions observed. At least one rock glacier is identified in each of the 11 westernmost states, but nearly 90% are found in just five; Colorado (n = 3889), Idaho (n = 1723), Montana (n = 1780), Utah (n = 834), and Wyoming (n = 849). Glaciers are …


Geomorphology Of Icy Debris Fans: Delivery Of Ice And Sediment To Valley Glaciers Decoupled From Icecaps, R. Craig Kochel, Jeffrey M. Trop, Robert W. Jacob Aug 2018

Geomorphology Of Icy Debris Fans: Delivery Of Ice And Sediment To Valley Glaciers Decoupled From Icecaps, R. Craig Kochel, Jeffrey M. Trop, Robert W. Jacob

Faculty Journal Articles

The pace and volume of mass flow processes contributing ice and sediment to icy debris fans (IDFs) were documented at sites in Alaska and New Zealand by integrating field observations, drone and time-lapse imagery, ground penetrating radar, and terrestrial laser scanning. Largely unstudied, IDFs are supraglacial landforms at the mouths of bedrock catchments between valley glaciers and icecaps. Time-lapse imagery recorded 300–2300 events reaching 15 fans during intervals from nine months to two years. Field observations noted hundreds of deposits trapped within catchments weekly that were later remobilized onto fans. Deposits were mapped on images taken three to four times …


Early Miocene Antarctic Glacial History: New Insights From Heavy Mineral Analysis From Andrill And–2a Drill Core Sediments, Francesco Iacoviello, Giovanna Giorgetti, Isabella Turbanti Memmi, Sandra Passchier Jul 2018

Early Miocene Antarctic Glacial History: New Insights From Heavy Mineral Analysis From Andrill And–2a Drill Core Sediments, Francesco Iacoviello, Giovanna Giorgetti, Isabella Turbanti Memmi, Sandra Passchier

Sandra Passchier

The present study deals with heavy mineral analysis of late Early Miocene marine sediments recovered in the McMurdo Sound region (Ross Sea, Antarctica) during the ANDRILL— SMS Project in 2007. The main objective is to investigate how heavy mineral assemblages reflect different source rocks and hence different provenance areas. These data contribute to a better understanding of East Antarctica ice dynamics in the Ross Sea sector during the Early Miocene (17.6–20.2 Ma), a time of long-term global warming and sea level rise. The AND-2A drill core recovered several stratigraphic intervals that span from Early Miocene to Pleistocene and it collected …


The Impact Of Ground-Based Glaciogenic Seeding On A Shallow Stratiform Cloud Over The Sierra Madre In Wyoming: A Multi-Sensor Study Of The 3 March 2012 Case, Binod Pokharel, Bart Geerts, Xiaoqin Jing Jul 2018

The Impact Of Ground-Based Glaciogenic Seeding On A Shallow Stratiform Cloud Over The Sierra Madre In Wyoming: A Multi-Sensor Study Of The 3 March 2012 Case, Binod Pokharel, Bart Geerts, Xiaoqin Jing

Plants, Soils and Climate Student Research

A case study is presented of the impact of ground-based glaciogenic seeding on a shallow, lightly precipitating orographic storm with abundant supercooled cloud droplets, but few ice particles. The storm was observed on 3 March 2012 as part of the AgI (silver iodide) Seeding Cloud Impact Investigating (ASCII) experiment in Wyoming. The cloud base temperature was about -9°C, and cloud tops were at about -16°C. The high concentration of small droplets and low ice particle concentration lead to natural snow growth, mainly by vapor diffusion. The question addressed here is whether the injection of ice nucleating particles (AgI) enhanced snow …


Joint Geodetic And Seismic Analysis Of Englacial And Subglacial Hydraulic Effects On Surface Crevassing Near A Seasonal, Glacier-Dammed Lake On Gornergletscher, Switzerland, Louis Stephen Garcia Jun 2018

Joint Geodetic And Seismic Analysis Of Englacial And Subglacial Hydraulic Effects On Surface Crevassing Near A Seasonal, Glacier-Dammed Lake On Gornergletscher, Switzerland, Louis Stephen Garcia

LSU Master's Theses

Glacial outburst floods are difficult to predict and threaten human life. These events are characterized by rapid draining of glacier-dammed lakes via the sub/englacial hydraulic network to the proglacial stream. The glacier-dammed lake on Gornergletscher in Switzerland, which fills and drains each summer, provides an opportunity to study this hazard. For three drainages (2004, 2006, and 2007), icequakes (IQ) are tracked as well as on-ice GPS movement. The seasonal seismic networks had 8 – 24 three-component stations and apertures of about 300 – 400 m on the glacier surface. The seasonal GPS arrays contained 4 – 8 GPS antennae on …


Developing A Risk Assessment Protocol To Quantify Distribution And Uptake Of Persistent Organic Pollutants In Glacial Outflows, Kimberley Rain Miner May 2018

Developing A Risk Assessment Protocol To Quantify Distribution And Uptake Of Persistent Organic Pollutants In Glacial Outflows, Kimberley Rain Miner

Electronic Theses and Dissertations

Pollutants released by industrialized nations between 1960 and 2004 have been transported northward through atmospheric processes and deposited into glaciated alpine ecosystems. Many of these chemicals retain their original structure and are absorbed into the biota thousands of miles away from where they were originally utilized. With a warming climate increasing the melt of alpine glaciers, these glaciers may be introducing growing amounts of toxins into the watershed. While studies have demonstrated the existence of resident pollutants within glaciated ecosystems, no one has developed a risk assessment to identify sources and quantity of risk posed by these compounds when released …


Multi-Channel Ground-Penetrating Radar For The Continuous Quantification Of Snow And Firn Density, Depth, And Accumulation, Tate Meehan May 2018

Multi-Channel Ground-Penetrating Radar For The Continuous Quantification Of Snow And Firn Density, Depth, And Accumulation, Tate Meehan

Boise State University Theses and Dissertations

A priority of ice sheet surface mass balance (SMB) prediction is ascertaining the surface density and annual snow accumulation. These forcing data are inputs for firn density models and can be used to inform remotely sensed ice sheet surface processes and to assess Regional Climate Model (RCM) skill. The Greenland Traverse for Accumulation and Climate Studies (GreenTrACS) retrieved 16 shallow firn cores and dug 42 snow pits along the Western percolation zone of the Greenland Ice Sheet (GrIS) during May and June of 2016 and 2017. I deployed and maintained a multi-channel 500 MHz ground-penetrating radar in a multi-offset configuration …


Glacial History Of The Tsagaan Gol- Potanin Glacier Valley, Altai Mountains, Mongolia, Mariah J. Radue May 2018

Glacial History Of The Tsagaan Gol- Potanin Glacier Valley, Altai Mountains, Mongolia, Mariah J. Radue

Electronic Theses and Dissertations

The last glacial termination (~19-11 ka) marks the end of the last ice age and the transition to modern interglacial conditions. The mechanisms that triggered deglaciation are unresolved. Various hypotheses for deglacial warming involve changes in Earth’s orbit, an 80-ppm increase in atmospheric CO­2, a ‘bipolar seesaw’ in oceanic-heat redistribution, and shifting wind belts. Here, I present a 10Be surface-exposure chronology for a system of glacial landforms in the Tsagaan Gol-Potanin Glacier valley in the Mongolian Altai (49°N, 88°E) to determine the nature of the termination in interior Asia. Located near the center of Earth’s largest continent, …


Ice Core Records Of West Greenland Melt And Climate Forcing, H.P. Marshall, T. Meehan Apr 2018

Ice Core Records Of West Greenland Melt And Climate Forcing, H.P. Marshall, T. Meehan

CGISS Publications and Presentations

Remote sensing observations and climate models indicate that the Greenland Ice Sheet (GrIS) has been losing mass since the late 1990s, mostly due to enhanced surface melting from rising summer temperatures. However, in situ observational records of GrIS melt rates over recent decades are rare. Here we develop a record of frozen meltwater in the west GrIS percolation zone preserved in seven firn cores. Quantifying ice layer distribution as a melt feature percentage (MFP), we find significant increases in MFP in the southernmost five cores over the past 50 years to unprecedented modern levels (since 1550 CE). Annual to decadal …


Mapping Bedrock Topography Of The Portage And Schoolcraft Nw 7.5’ Quadrangles, Kalamazoo Co. Mi, Using The Hvsr Passive Seismic Method, Benjamin B. Seiderman Apr 2018

Mapping Bedrock Topography Of The Portage And Schoolcraft Nw 7.5’ Quadrangles, Kalamazoo Co. Mi, Using The Hvsr Passive Seismic Method, Benjamin B. Seiderman

Masters Theses

This study utilizes the Horizontal to Vertical Spectral Ratio (HVSR) technique to map bedrock topography in the Portage and Schoolcraft NW quadrangles, Kalamazoo Co., MI, looking for buried bedrock valleys. Glacial sediment-landform assemblages dominate the study area, due to multiple advances of the Laurentide Ice Sheet (LIS). Tunnel valleys, which are one type of buried valley, are eroded by subglacial meltwater and commonly filled with the coarser varieties of glacial outwash, making them potential aquifers. The HVSR technique measures the ratio of horizontal to vertical ground motion, excited by ambient seismic noise, resulting in a peak at the resonance frequency. …


Geologic Mapping Of The Bronson North And Bronson South 7.5-Minute Quadrangles, Branch County, Michigan, Karl John Backhaus Apr 2018

Geologic Mapping Of The Bronson North And Bronson South 7.5-Minute Quadrangles, Branch County, Michigan, Karl John Backhaus

Masters Theses

This study contributes to a better understanding of the glacial history of southwest Michigan through detailed surficial geologic and bedrock topography mapping within the Bronson North and Bronson South Quadrangles in Branch County, Michigan. This project was supported during the summer of 2017 by the USGS EDMAP program in conjunction with the Michigan Geological Survey. Hand-auger borings, grain size analysis tests, passive seismic depth-to-bedrock measurements, and ground penetrating radar transects were collected for this study. There are 350 feet of bedrock relief from west to east across the quadrangles, including a bedrock cuesta of Mississippian Coldwater Shale. This cuesta underlies …


Carbon Flux And Weathering Processes In Icelandic Glacial-Fed Rivers, Allison Quiroga Apr 2018

Carbon Flux And Weathering Processes In Icelandic Glacial-Fed Rivers, Allison Quiroga

Masters Theses & Specialist Projects

An investigation into the carbon dynamics and weathering processes occurring in Icelandic glacial-fed streams was conducted during the spring to summer seasonal transition in June of 2017. Four major outlet rives were sampled from the glaciers of Gígjökull, Steinsholtsjökull, Sólheimajökull, and Falljökull. Markarfljót, the major river that Gígjökull, Steinsholtsjökull, and many other glaciers drain into, was also sampled. Longitudinal sampling occurred at all sites to capture downstream trends in the hydrogeochemistry and carbon dynamics. Distinct differences in geochemistry between glacier surface meltwater, sub-glacial waters, pro-glacial lake water, and post-mixed downstream samples were evident in the data. Glacier surface streams were …


Mapping And Interpreting The Glacial Geology Of Pictured Rocks National Lakeshore, Michigan, Sarah M. Vandermeer Apr 2018

Mapping And Interpreting The Glacial Geology Of Pictured Rocks National Lakeshore, Michigan, Sarah M. Vandermeer

Dissertations

Pictured Rocks National Lakeshore is among the most popular parks in Michigan, yet prior to this study, it was the only National Park that lacked a detailed surficial geology map characterizing the distribution of sediments and landforms. Additionally, much of the landscape remained unexplored. These factors prevented thorough interpretations of landscape development and evolution. This research aims to map and further explore the relationship of glacial sediments and landforms throughout Pictured Rocks to refine and expand the current understanding of glacial events that shaped this landscape.

A new, detailed (1:24,000-scale) surficial geology map of the ten 7.5-minute quadrangles that contain …


Topographic Control On Post-Lgm Groundings Of The West Antarctic Ice Sheet In The Whales Deep Basin, Eastern Ross Sea, Matthew Danielson Mar 2018

Topographic Control On Post-Lgm Groundings Of The West Antarctic Ice Sheet In The Whales Deep Basin, Eastern Ross Sea, Matthew Danielson

LSU Master's Theses

By the peak of the Last Glacial Maximum (LGM), the West Antarctic Ice Sheet (WAIS) had advanced to the outer continental shelf of eastern Ross Sea trough basins. During the post-LGM retreat, the WAIS paused several times within 75 km of the Whales Deep Basin (WDB) shelf edge. An overlapping stack of seven grounding zone wedges (GZWs) records the locations of these groundings. Here we used ~7500 km of seismic reflection data to map the subglacial unconformity that was eroded when WAIS was grounded at the shelf edge, i.e., prior to the deposition of the backstepping GZWs. With respect to …


Drivers Of Solar Radiation Variability In The Mcmurdo Dry Valleys, Antarctica, Maciej K. Obryk, Andrew G. Fountain, Peter T. Doran Mar 2018

Drivers Of Solar Radiation Variability In The Mcmurdo Dry Valleys, Antarctica, Maciej K. Obryk, Andrew G. Fountain, Peter T. Doran

Geology Faculty Publications and Presentations

Annually averaged solar radiation in the McMurdo Dry Valleys, Antarctica has varied by over 20 W m−2 during the past three decades; however, the drivers of this variability are unknown. Because small differences in radiation are important to water availability and ecosystem functioning in polar deserts, determining the causes are important to predictions of future desert processes. We examine the potential drivers of solar variability and systematically eliminate all but stratospheric sulfur dioxide. We argue that increases in stratospheric sulfur dioxide increase stratospheric aerosol optical depth and decrease solar intensity. Because of the polar location of the McMurdo Dry Valleys …


Spectral Signatures Of Submicron Scale Light-Absorbing Impurities In Snow And Ice Using Hyperspectral Microscopy, Farra Dal Anna, Susan Kaspari, James Beach, Thomas D. Bucheli, Michael Schaepman, Margit Schwikowski Jan 2018

Spectral Signatures Of Submicron Scale Light-Absorbing Impurities In Snow And Ice Using Hyperspectral Microscopy, Farra Dal Anna, Susan Kaspari, James Beach, Thomas D. Bucheli, Michael Schaepman, Margit Schwikowski

Geological Sciences Faculty Scholarship

Light-absorbing impurities (LAI) can darken snow and ice surfaces, reduce snow/ice albedo and accelerate melt. Efforts to allocate the relative contribution of different LAI to snow/ice albedo reductions have been limited by uncertainties in the optical properties of LAI. We developed a new method to measure LAI spectral reflectance at the submicron scale by modifying a Hyperspectral Imaging Microscope Spectrometer (HIMS). We present the instrument’s internal calibration, and the overall small influence of a particle’s orientation on its measured reflectance spectrum. We validated this new method through the comparison with a field spectroradiometer by measuring different standard materials. Measurements with …


Spatio-Temporal Variability Of Processes Across Antarctic Ice-Bed–Ocean Interfaces, Florence Colloni, Laura De Santis, Christine S. Siddoway, Andrea Bergamasco, Nicholas R. Golledge, Gerrit Lohmann, Sandra Passchier, Martin J. Siegert Jan 2018

Spatio-Temporal Variability Of Processes Across Antarctic Ice-Bed–Ocean Interfaces, Florence Colloni, Laura De Santis, Christine S. Siddoway, Andrea Bergamasco, Nicholas R. Golledge, Gerrit Lohmann, Sandra Passchier, Martin J. Siegert

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Understanding how the Antarctic ice sheet will respond to global warming relies on knowledge of how it has behaved in the past. The use of numerical models, the only means to quantitatively predict the future, is hindered by limitations to topographic data both now and in the past, and in knowledge of how subsurface oceanic, glaciological and hydrological processes interact. Incorporating the variety and interplay of such processes, operating at multiple spatio-temporal scales, is critical to modeling the Antarctic’s system evolution and requires direct observations in challenging locations. As these processes do not observe disciplinary boundaries neither should our future …


Evidence For Ephemeral Middle Eocene To Early Oligocene Greenland Glacial Ice And Pan-Arctic Sea Ice, Aradhna Tripati, Dennis Darby Jan 2018

Evidence For Ephemeral Middle Eocene To Early Oligocene Greenland Glacial Ice And Pan-Arctic Sea Ice, Aradhna Tripati, Dennis Darby

OES Faculty Publications

Earth's modern climate is defined by the presence of ice at both poles, but that ice is now disappearing. Therefore understanding the origin and causes of polar ice stability is more critical than ever. Here we provide novel geochemical data that constrain past dynamics of glacial ice on Greenland and Arctic sea ice. Based on accurate source determinations of individual ice-rafted Fe-oxide grains, we find evidence for episodic glaciation of distinct source regions on Greenland as far-ranging as ~68°N and ~80°N synchronous with ice-rafting from circum-Arctic sources, beginning in the middle Eocene. Glacial intervals broadly coincide with reduced CO2 …


Glacier Recession And The Response Of Summer Streamflow In The Pacific Northwest United States, 1960–2099, Chris Frans, Erkan Istanbulluoglu, Dennis P. Lettenmaier, Andrew G. Fountain, Jon L. Riedel Jan 2018

Glacier Recession And The Response Of Summer Streamflow In The Pacific Northwest United States, 1960–2099, Chris Frans, Erkan Istanbulluoglu, Dennis P. Lettenmaier, Andrew G. Fountain, Jon L. Riedel

Geology Faculty Publications and Presentations

The Pacific Northwest is the most highly glacierized region in the conterminous United States (858 glaciers; 466 km2). These glaciers have displayed ubiquitous patterns of retreat since the 1980s mostly in response to warming air temperatures. Glacier melt provides water for downstream uses including agricultural water supply, hydroelectric power generation, and for ecological systems adapted to cold reliable streamflow. While changes in glacier area have been studied within the region over an extended period of time, the hydrologic consequences of these changes are not well defined. We applied a high‐resolution glacio‐hydrological model to predict glacier mass balance, glacier area, and …


Internal Composition, Structure, And Hydrological Significance Of Rock Glaciers In The Eastern Cascades, Washington, Adam Riffle Jan 2018

Internal Composition, Structure, And Hydrological Significance Of Rock Glaciers In The Eastern Cascades, Washington, Adam Riffle

All Master's Theses

Low summer river base flow places a strain on natural and economic resources of the Eastern Cascades. A major contributor to stream flow in this region is snow pack which has declined over the past few decades because of a warming climate. In addition, glacial runoff, which contributes significantly to base flow in summer dry periods, will diminish from glacial recession. However, rock glaciers, because their internal ice (i.e., permafrost) is insulated by an outer debris layer, react slowly to climate change, thus acting as sinks for ice and liquid water storage in mountain environments. This study utilized ground penetrating …