Glaciology Commons^™

Trajectory Analysis Of Black Carbon In The Arctic Region, Kimberly Gottschalk

PSU McNair Scholars Online Journal

Black carbon (BC) is a troubling particulate. Commonly known as soot, BC forms through the incomplete combustion of fossil fuels, biofuels, and biomass. It has a very low albedo compared to natural particulates making it a very efficient absorber of solar radiation. As BC is deposited on snow and ice, albedo is decreased - enhancing solar heating and increasing meltwater production. With rising air temperatures, melting rates of polar ice are increasing and are being enhanced by BC, leading to accelerated global sea level rise.

This study aimed to document sources and deposition areas of BC in the Arctic. Utilizing …

Basal Characteristics Of The Main Sticky Spot On The Ice Plain Of Whillans Ice Stream, Antarctica, Tarun Luthra, Sridhar Anandakrishnan, J. Paul Winberry, Richard B. Alley, Nicholas Holschuh

Geological Sciences Faculty Scholarship

Understanding the processes that affect streaming ice flow and the mass balance of glaciers and ice sheets requires sound knowledge of their subglacial environments. Previous studies have shown that an extensive deformable subglacial sediment layer favors fast ice-stream flow. However, areas of high basal drag, termed sticky spots, are of particular interest because they inhibit the fast flow of the overriding ice. The stick-slip behavior of Whillans Ice Stream (WIS) is perhaps the most conspicuous manifestation of a subglacial sticky spot. We present new ice-thickness and seismic-reflection measurements collected over the main sticky spot in the ice plain of WIS, …

The Last Glacial Maximum In Central North Island, New Zealand: Palaeoclimate Inferences From Glacier Modelling, Shaun. R. Eaves, Andrew N. Mackintosh, Brian M. Anderson, Alice M. Doughty

Dartmouth Scholarship

Quantitative palaeoclimate reconstructions provide data for evaluating the mechanisms of past, natural climate variability. Geometries of former mountain glaciers constrained by moraine mapping afford the opportunity to reconstruct palaeoclimate, due to the close relationship between ice extent and local climate. In this study, we present results from a series of experiments using a 2D coupled energy-balance/ice-flow model that investigate the palaeoclimate significance of Last Glacial Maximum m

oraines within nine catchments in the central North Island, New Zealand. We find that the former ice limits can be simulated when present-day temperatures are reduced by between 4 and 7 ◦C, if …

Twentieth-Century Warming Preserved In A Geladaindong Mountain Ice Core, Central Tibetan Plateau, Yulan Zhang, Shichang Kang, Bjorn Grigholm, Yongjun Zhang, Susan Kaspari, Uwe Morgenstern, Jiawen Ren, Dahe Qin, Paul A. Mayewski, Qianggong Zhang, Zhiyuan Cong, Mika Sillanpää, Margit Schwikowski, Feng Chen

All Faculty Scholarship for the College of the Sciences

High-resolution δ¹⁸O records from a Geladaindong mountain ice core spanning the period 1477-1982 were used to investigate past temperature variations in the Yangtze River source region of the central Tibetan Plateau (TP). Annual ice-core δ¹⁸O records were positively correlated with temperature data from nearby meteorological stations, suggesting that the δ¹⁸O record represented the air temperature in the region. A generally increasing temperature trend over the past 500 years was identified, with amplified warming during the 20th century. A colder stage, spanning before the 1850s, was found to represent the Little Ice Age with colder …

Distributed Modeling Of Ablation (1996–2011) And Climate Sensitivity On The Glaciers Of Taylor Valley, Antarctica, Matthew J. Hoffman, Andrew G. Fountain, Glen E. Liston

Geology Faculty Publications and Presentations

The McMurdo Dry Valleys of Antarctica host the coldest and driest ecosystem on Earth, which is acutely sensitive to the availability of water coming from glacial runoff. We modeled the spatial variability in ablation and assessed climate sensitivity of the glacier ablation zones using 16 years of meteorological and surface mass-balance observations collected in Taylor Valley. Sublimation was the primary form of mass loss over much of the ablation zones, except for near the termini where melt, primarily below the surface, dominated. Microclimates in ~10 m scale topographic basins generated melt rates up to ten times higher than over smooth …

Processes Controlling Carbon Cycling In Antarctic Glacier Surface Ecosystems, Elizabeth A. Bagshaw, Martyn Tranter, Jemma L. Wadham, Andrew G. Fountain, A. Dubnick, S. Fitzsimons

Geology Faculty Publications and Presentations

Glacier surface ecosystems, including cryoconite holes and cryolakes, are significant contributors to regional carbon cycles. Incubation experiments to determine the net production (NEP) of organic matter in cryoconite typically have durations of 6-24 hours, and produce a wide range of results, many of which indicate that the system is net heterotrophic. We employ longer term incubations to examine the temporal variation of NEP in cryoconite from the McMurdo Dry Valleys, Antarctica to examine the effect of sediment disturbance on system production, and to understand processes controlling production over the lifetimes of glacier surface ecosystems. The shorter-term incubations have durations of …

Influence Of Sea Ice On Arctic Precipitation, Ben G. Kopec, Xiahong Feng, Fred A. Michel, Eric S. Posmentier

Dartmouth Scholarship

Global climate is influenced by the Arctic hydrologic cycle, which is, in part, regulated by sea ice through its control on evaporation and precipitation. However, the quantitative link between precipitation and sea ice extent is poorly constrained. Here we present observational evidence for the response of precipitation to sea ice reduction and assess the sensitivity of the response. Changes in the proportion of moisture sourced from the Arctic with sea ice change in the Canadian Arctic and Greenland Sea regions over the past two decades are inferred from annually averaged deuterium excess (d-excess) measurements from six sites. Other influences on …

Pinedale Glacial History Of The Upper Arkansas River Valley: New Moraine Chronologies, Modeling Results And Geologic Mapping, Avriel D. Schweinsberg, Jason P. Briner, Ralph R. Shroba, Joseph M. Licciardi, Eric M. Leonard, Keith A. Brugger, Charles M. Russell

Geology Publications

This field trip guidebook chapter outlines the glacial history of the upper Arkansas River valley, Colorado, and builds on a previous GSA field trip to the same area in 2010. The following will be presented: (1) new cosmogenic 10Be exposure ages of moraine boulders from the Pinedale and Bull Lake glaciations (Marine Isotope Stages 2 and 6, respectively) located adjacent to the Twin Lakes Reservoir, (2) numerical modeling of glaciers during the Pinedale glaciation in major tributaries draining into the upper Arkansas River, (3) discharge estimates for glacial-lake outburst floods in the upper Arkansas River valley, and (4) 10Be ages …

Art Above 66° 33', Augustana College, Rock Island Illinois

2016-2017

66˚ 33' is the latitude of the Arctic and Antarctic Circles, and this exhibition considers these geographic areas as inspiration for the visual arts. In addition, it utilizes the visual arts as a mode by which to encourage viewers to more deeply engage with the planet’s most northerly and southerly regions. It considers the issues, history and environment of the regions, spanning media, process and subject – from the figural to the abstract, tactile to sound, analog to digital.

This exhibition was a collaboration with the Augustana Center for Polar Studies.

#ArtAbove66

ARTISTS: Michael Bartalos, Cape Dorset Prints from the …

Modelling The Response Of Ice Shelf Basal Melting To Different Ocean Cavity Environmental Regimes, David E. Gwyther, Eva A. Cougnon, Benjamin K. Galton-Fenzi, Jason L. Roberts, John R. Hunter, Michael S. Dinniman

CCPO Publications

We present simulation results from a version of the Regional Ocean Modeling System modified for ice shelf/ocean interaction, including the parameterisation of basal melting by molecular diffusion alone. Simulations investigate the differences in melting for an idealised ice shelf experiencing a range of cold to hot ocean cavity conditions. Both the pattern of melt and the location of maximum melt shift due to changes in the buoyancy-driven circulation, in a different way to previous studies. Tidal forcing increases both the circulation strength and melting, with the strongest impact on the cold cavity case. Our results highlight the importance of including …

High-Resolution Ground-Penetrating Radar Profiles Of Perennial Lake Ice In The Mcmurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, And Subbottom, Hilary A. Dugan, Steven A. Arcone, Maciej K. Obryk, Peter T. Doran

Geology Faculty Publications and Presentations

Ground-penetrating radar (GPR) is not commonly used to study lake ice, and in general, the ground-based use of radar frequencies greater than 500 MHz in cryosphere geophysics is rare, due to a general interest in deeper stratigraphy and the difficulty of extensive profiling over rough snow surfaces. Our goal was to find further information on the origin of the deposition and formation of intra-ice layers, bottom topography, and subbottom deposits using GPR with pulses centered near 850 MHz on two permanently ice-covered lakes in the Mc- Murdo Dry Valleys, Antarctica. The profiles were obtained using a one-person sled operation over …

Response Of Antarctic Cryoconite Microbial Communities To Light, Elizabeth A. Bagshaw, Jemma L. Wadham, Martyn Tranter, Rupert Perkins, Alistair Morgan, Christopher J. Williamson, Andrew G. Fountain, Sean Fitzsimons, Ashley Dubnick

Geology Faculty Publications and Presentations

Microbial communities on polar glacier surfaces are found dispersed on the ice surface, or concentrated in cryoconite holes and cryolakes, which are accumulations of debris covered by a layer of ice for some or all of the year. The ice lid limits the penetration of photosynthetically available radiation (PAR) to the sediment layer, since the ice attenuates up to 99% of incoming radiation. This suite of field and laboratory experiments demonstrates that PAR is an important control on primary production in cryoconite and cryolake ecosystems. Increased light intensity increased efficiency of primary production in controlled laboratory incubations of debris from …

Mechanism Of Seasonal Arctic Sea Ice Evolution And Arctic Amplification, Kwang-Yul Kim, Benjamin D. Hamlington, Hanna Na, Jinju Kim

CCPO Publications

Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents-Kara seas. Excessive turbulent heat flux through the sea …

Apparent Glacially Induced Structural Controls On Limestone Conduit Development In Ohio Caverns, United States, Adrienne M. Watts, Ira D. Sasowsky

International Journal of Speleology

Rock discontinuities such as bedding planes and joints are important controls on the form that caves take. We examined structural controls on the development of Ohio Caverns. The cave formed in Devonian limestone underlying a small bedrock knob (Mt. Tabor) within the Interior Lowland province, United States. The area has been overridden by continental glaciation multiple times. The bedrock is pervasively fractured, with many curved and wavy near-vertical fractures showing many different orientations. In the case of Ohio Caverns, it appears that the controlling fractures in map view may not be joints sensu stricto, but rather some combination of …

A College Level Geology Field Trip In Western Connecticut And Vicinity, Stanley Schleifer, Nazrul I. Khandaker, Keshaw Narine, Ezazul Haque, Ratan Dhar

Publications and Research

There are a number of excellent locations for field exposure for college students in, and around Western Connecticut. These are accessible for a one day field trip within striking distance of New York City, Bridgeport and New Haven, CT and other nearby locations. They are also suitable for an expanded weekend field trip. The field locations include; Kent Falls State Park, Kent, CT, Dinosaur State Park, Rocky Hill, CT, the Hubbard Mining Museum, Kent, CT, Bash Bish Falls in Mt. Washington, Massachusetts, Macedonia Brook State Park in Kent, CT and various outcrops exposed along U. S. Route 7 north of …

Effects Of Changes In Moisture Source And The Upstream Rainout On Stable Isotopes In Precipitation – A Case Study In Nanjing, Eastern China, Y. Tang, H. Pang, W. Zhang, Y. Li, Shuang-Ye Wu, S. Hou

Department of Earth, Environment and Sustainability Faculty Publications

In the Asian monsoon region, variations in the stable isotopic composition of speleothems have often been attributed to the "amount effect". However, an increasing number of studies suggest that the "amount effect" in local precipitation is insignificant or even non-existent. To explore this issue further, we examined the variability of daily stable isotopic composition (δ18O) in precipitation from September 2011 to November 2014 in Nanjing, eastern China. We found that intra-seasonal variations of δ18O during summer were not significantly correlated with local rainfall amount but could be linked to changes in the moisture source location and rainout processes in the …

Geology Of The Steens Area, Jane Claire Dirks-Edmunds

Jane Claire Dirks-Edmunds Documents

This document is part of a larger discussion in the Dr. Jane Claire Dirks-Edmunds Papers on the geology of Steens Mountain, a large fault-block mountain in Harney County, Oregon. Often confused for a mountain range because of its size and scope, Steens Mountain lies near the Oregon-Nevada border.

For a full-text searchable version of this document, refer to the Additional Files below.

Coastal Ice-Core Record Of Recent Northwest Greenland Temperature And Sea-Ice Concentration, Erich C. Osterberg, Robert L. Hawley, Gifford Wong, Ben Kopec, David Ferris, Jennifer Howley

Dartmouth Scholarship

Coastal ice cores provide an opportunity to investigate regional climate and sea-ice variability in the past to complement hemispheric-scale climate reconstructions from ice-sheet-interior ice cores. Here we describe robust proxies of Baffin Bay temperature and sea-ice concentration from the coastal 2Barrel ice core collected in the Thule region of northwest Greenland. Over the 1990–2010 record, 2Barrel annually averaged methanesulfonic acid (MSA) concentrations are significantly correlated with May–June Baffin Bay sea-ice concentrations and summer temperatures. Higher MSA is observed during warmer years with less sea ice, indicative of enhanced primary productivity in Baffin Bay. Similarly, 2Barrel annually averaged deuterium excess (d-excess) …

Dynamics Of Thermally Induced Ice Streams Simulated With A Higher-Order Flow Model, Douglas Brinkerhoff, Jesse Johnson

Computer Science Faculty Publications

We use a new discretization technique to solve the higher-order thermomechanically coupled equations of glacier evolution. We find that under radially symmetric continuum equations, small perturbations in symmetry due to the discretization are sufficient to produce the initiation of non-symmetric thermomechanical instabilities which we interpret as ice streams, in good agreement with previous studies which have indicated a similar instability. We find that the inclusion of membrane stresses regularizes the size of predicted streams, eliminating the ill-posedness evident in previous investigations of ice stream generation through thermomechanical instability. Ice streams exhibit strongly irregular periodicity which is influenced by neighboring ice …

Glacier Change On The Three Sisters Volcanoes, Oregon: 1900-2010, Justin George Ohlschlager

Dissertations and Theses

A glacier responds to changes in climate by subsequent retreat and advance as a result of changes in snow inputs and outputs. Understanding these changes is important because shrinking glaciers limit and diminish local water resources. They contribute to alpine runoff in the late-summer months by delaying the maximum runoff until late in the melt season. A comprehensive glacier and perennial snowfield inventory has not been completed for the Three Sisters in Central Oregon. Using aerial photography, Digital Elevation Models (DEMs), previous studies, and historical ground based photographs these glacier and perennial snowfields were defined and their surface area change …

Temperature Distribution And Thermal Anomalies Along A Flowline Of The Greenland Ice Sheet, Joel A. Harrington, Neil F. Humphrey, Joel T. Harper

Geosciences Faculty Publications

Englacial and basal temperature data for the Greenland ice sheet (GrIS) are sparse and mostly limited to deep interior sites and ice streams, providing an incomplete representation of the thermal state of ice within the ablation zone. Here we present 11 temperature profiles at five sites along a 34km east-west transect of West Greenland. These profiles depict ice temperatures along a flowline and local temperature variations between closely spaced boreholes. A temperate basal layer is present in all profiles, increasing in thickness in the flow direction, where it expands from about 3% of ice height furthest inland to 100% at …

The Role Of Damage And Recrystallization In The Elastic Properties Of Columnar Ice, Scott A. Snyder, Erland M. Schulson, Carl E. Renshaw

Dartmouth Scholarship

Effects of damage on elastic properties were studied in columnar-grained specimens of freshwater and saline ice, subjected, at −10°C, to varying levels of inelastic strain. The ice was compressed uniaxially at constant strain rates up to 0.20 strain, which caused localized recrystallization and imparted damage in the form of non-propagating cracks. Damage was quantified in terms of dimensionless crack density, which, along with recrystallized area fraction, was determined from thin sections. The change in porosity due to stress-induced cracks served as another indicator of damage. Elastic properties were derived using P-wave and S-wave ultrasonic transmission velocities measured in across-column directions …

Dye Tracing To Determine Flow Properties Of Hydrocarbon-Polluted Rabots Glaciär, Kebnekaise, Sweden, Caroline C. Clason, C. Coch, J. Jarsjö, Keith A. Brugger, P. Jansson, G. Rosqvist

Geology Publications

Over 11 000 L of kerosene was deposited on the surface of Rabots glaciär on the Kebnekaise Massif, northern Sweden, following the crash of a Royal Norwegian Air Force aircraft in March 2012. An environmental monitoring programme was subsequently commissioned, including a series of dye tracing experiments during the 2013 melt season, conducted to investigate the transport of pollutants through the glacier hydrological system. This experimental set-up provided a basis from which we could gain new insight into the internal hydrological system of Rabots glaciär. Results of dye tracing experiments reveal a degree of homogeneity in the topology of the …

Dramatic Loss Of Glacier Accumulation Area On The Tibetan Plateau Revealed By Ice Core Tritium And Mercury Records, S. Kang, F. Wang, U. Morgenstern, Y. Zhang, B. Grigholm, Susan D. Kaspari, M. Schwikowski, J. Ren, T. Yao, D. Qin, P. A. Mayewski

All Faculty Scholarship for the College of the Sciences

Two ice cores were retrieved from high elevations (~5800 m a.s.l.) at Mt. Nyainqêntanglha and Mt. Geladaindong in the southern and central Tibetan Plateau region. The combined tracer analysis of tritium (³H), ²¹⁰Pb and mercury, along with other chemical records, provided multiple lines of evidence supporting that the two coring sites had not received net ice accumulation since at least the 1950s and 1980s, respectively. These results implied an annual ice loss rate of more than several hundred millimeter water equivalent over the past 30–60 years. Both mass balance modeling at the sites and in situ data …

Interface Friction Parameters For The Mathematical Modeling Of Shell Structures With Infill, Alexander T. Bekker, Nikita Ya. Tsimbelman, Tatiana I. Chernova, Vadim D. Bruss, Ömer Bilgin

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Thin metal or reinforced concrete shells with granular infill structures are considered in this article. These structures are massive and they are used as support for the construction of berthing quays, piers, artificial islands, shore protection, and other structures of coastal infrastructure. It is more convenient to use the thin shell structures during the development of the Arctic shelf, because it is possible to install them from the ice side. In addition, it is possible to enhance the technology and install thin shells with infill on deeper solid foundation layers. A mathematical model for the stresses on a compressible foundation …

Threshold Behavior Of A Marine‐Based Sector Of The East Antarctic Ice Sheet In Response To Early Pliocene Ocean Warming, Melissa A. Hansen, Sandra Passchier, Boo‐Keun Khim, Buhan Song, Trevor Williams

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

We investigate the stability of the East Antarctic Ice Sheet (EAIS) on the Wilkes Land continental margin, Antarctica, utilizing a high‐resolution record of ice‐rafted debris (IRD) mass accumulation rates (MAR) from Integrated Ocean Drilling Program Site U1359. The relationship between orbital variations in the IRD record and climate drivers was evaluated to capture changes in the dynamics of a marine‐based ice sheet in response to early Pliocene warming. Three IRD MAR excursions were observed and confirmed via scanning electron microscope microtextural analysis of sand grains. Time series analysis of the IRD MAR reveals obliquity‐paced expansions of the ice sheet to …

Reconstructing Thermal Properties Of Firn At Summit, Greenland, From A Temperature Profile Time Series, Alexandra L. Giese, Robert L. Hawley

Dartmouth Scholarship

We have constrained the value for thermal diffusivity of near-surface snow and firn at Summit Station, Greenland, using a Fourier-type analysis applied to hourly temperature measurements collected from eight thermistors in a closed-off, air-filled borehole between May 2004 and July 2008. An implicit, finite-difference method suggests that a bulk diffusivity of ∼25 ± 3m2 a−1 is the most reasonable for representing macroscale heat transport in the top 30 m of firn and snow. This value represents an average diffusivity and, in a conduction-only model, generates temperature series whose phase shifts with depth most closely match those of the Summit borehole …

Accelerated Glacier Melt On Snow Dome, Mount Olympus, Washington, Usa, Due To Deposition Of Black Carbon And Mineral Dust From Wildfire, Susan D. Kaspari, S. Mckenzie Skiles, Ian Delaney, Daniel Dixon, Thomas H. Painter

All Faculty Scholarship for the College of the Sciences

Assessing the potential for black carbon (BC) and dust deposition to reduce albedo and accelerate glacier melt is of interest in Washington because snow and glacier melt are an important source of water resources, and glaciers are retreating. In August 2012 on Snow Dome, Mount Olympus, Washington, we measured snow surface spectral albedo and collected surface snow samples and a 7 m ice core. The snow and ice samples were analyzed for iron (Fe, used as a dust proxy) via inductively coupled plasma sector field mass spectrometry, total impurity content gravimetrically, BC using a single-particle soot photometer (SP2), and charcoal …

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

ANDRILL Research and Publications

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 …

Heat Sources Within The Greenland Ice Sheet: Dissipation, Temperate Paleo-Firn And Cryo-Hydrologic Warming, M. P. Lüthi, C. Ryser, L. C. Andrews, G. A. Catania, M. Funk, R. L. Hawley

Dartmouth Scholarship

Ice temperature profiles from the Greenland Ice Sheet contain information on the deformation history, past climates and recent warming. We present full-depth temperature profiles from two drill sites on a flow line passing through Swiss Camp, West Greenland. Numerical modeling reveals that ice temperatures are considerably higher than would be expected from heat diffusion and dissipation alone. The possible causes for this extra heat are evaluated using a Lagrangian heat flow model. The model results reveal that the observations can be explained with a combination of different processes: enhanced dissipation (strain heating) in ice-age ice, temperate paleo-firn, and cryo-hydrologic warming …