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The University of Maine

Series

2004

Articles 1 - 30 of 39

Full-Text Articles in Physical Sciences and Mathematics

Computer Simulations Of Ions, Dipoles, Dna Elasticity And Interfaces, Jayendran Rasaiah Dec 2004

Computer Simulations Of Ions, Dipoles, Dna Elasticity And Interfaces, Jayendran Rasaiah

University of Maine Office of Research Administration: Grant Reports

Jay Rasaiah of the University of Maine is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research on condensed phase fluid systems. Proposed research focuses on four topics: 1) ionic mobility and association, water structure and dynamics in supercritical solutions; 2) phase transitions of polar fluids; 3) intrinsic elasticity of DNA; and 4) structure and dynamics of water and ions in contact with hydrophobic surfaces and electrodes. Rasaiah will use a combination of molecular simulations and formal theory to attack these problems. Computer simulations involving water will use an extended SPC/E model that includes …

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Sger: Supercritical Levitation Polymerization And Processing, Erdogan Kiran Dec 2004

Sger: Supercritical Levitation Polymerization And Processing, Erdogan Kiran

University of Maine Office of Research Administration: Grant Reports

In supercritical polymerization processes, polymer chains grow to molecular weights determined by their solubility under the prevailing density (or pressure and temperature) conditions of the solvent. Further growth in the chain length results in phase separation and leads to precipitation. In this project, polymerizations will be conducted under isopycnic conditions by adjusting the density of the solvent environment to be identical to the density of the polymer formed. This iso- density operation is expected to insure levitation by buoyancy and prevent precipitation of the phase-separated polymer. Density adjustments are readily achievable for supercritical solvents through manipulation of either the pressure …

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Cmg Training In Spatio-Temporal Statistical Analysis Of Multi-Platform Ocean Optical Observations, Mary Jane Perry Oct 2004

Cmg Training In Spatio-Temporal Statistical Analysis Of Multi-Platform Ocean Optical Observations, Mary Jane Perry

University of Maine Office of Research Administration: Grant Reports

This project will be a five-week summer school on the topic of spatio-temporal statistical analysis and its application to multi-platform, multi-sensor bio-optical oceanic data. The summer school seeks to address some of the analysis challenges anticipated as the Integrated Ocean Observing System is established. These are associated with the very diverse range of spatial and temporal sampling afforded by the different components of such a system and contemporaneous process experiments. Statistical experts in spatial information engineering with experience in collaboration with ocean scientists will discuss some of the modern tools for statistical analysis of such data and associated challenges, while …

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Coastal Change And Beach Ridges Along The Northwest Coast Of Peru: Image And Gis Analysisof The Chira, Piura, And Colán Beach-Ridge Plains, Stacy Shafer Rogers, Daniel H. Sandweiss, Kirk A. Maasch, Daniel F. Belknap, Peggy Agouris Oct 2004

Coastal Change And Beach Ridges Along The Northwest Coast Of Peru: Image And Gis Analysisof The Chira, Piura, And Colán Beach-Ridge Plains, Stacy Shafer Rogers, Daniel H. Sandweiss, Kirk A. Maasch, Daniel F. Belknap, Peggy Agouris

Anthropology Faculty Scholarship

Since approximately 5200 cal yrs BP, five sets of eight to nine beach ridges were built and preserved along the northwestern Peruvian coastal desert (3o30'S-9oS). Potential ridge-building mechanisms in the hyper-arid environment of northwest Peru include El Nifio floods and storms, seismic activity, and sea-level change, as well as more gradualc limate changes that affectedc oastal morphologyI. mage processinga nd GeographicI nformationS ystem (GIS) methods were used to analyze aerial photographs and measure historic coastal patterns along three beach-ridge plains over a 37-year time period. Coastal features were digitized from image mosaics of each ridge plain at different time intervals …

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Basal Melting Along The Floating Part Of Byrd Glacier, James P. Kenneally, Terence J. Hughes Sep 2004

Basal Melting Along The Floating Part Of Byrd Glacier, James P. Kenneally, Terence J. Hughes

Earth Science Faculty Scholarship

A mass balance calculation was made for the floating part of Byrd Glacier, using 1978-79 ice elevation and velocity data, over the 45 km of Byrd Glacier from its grounding line to where it leaves its fjord and merges with the Ross Ice Shelf. Smoothed basal melting rates were relatively uniform over this distance and averaged 12 +/- 2 m yr(-1).

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Fracture And Back Stress Along The Byrd Glacier Flowband On The Ross Ice Shelf, James P. Kenneally, Terence J. Hughes Sep 2004

Fracture And Back Stress Along The Byrd Glacier Flowband On The Ross Ice Shelf, James P. Kenneally, Terence J. Hughes

Earth Science Faculty Scholarship

East Antarctic ice discharged by Byrd Glacier continues as a flowband to the calving front of the Ross Ice Shelf. Flow across the grounding line changes from compressive to extensive as it leaves the fjord through the Transantarctic Mountains occupied by Byrd Glacier. Magnitudes of the longitudinal compressive stress that suppress opening of transverse tensile cracks are calculated for the flowband. As compressive back stresses diminish, initial depths and subsequent growth of these cracks, and their spacing, are calculated using theories of elastic and ductile fracture mechanics. Cracks are initially about one millimeter wide, with approximately 30 in depths and …

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Polar Mm5 Simulations Of The Winter Climate Of The Laurentide Ice Sheet At The Lgm, David H. Bromwich, E. Richard Toracinta, Helin Wei, Robert J. Oglesby, James L. Fastook, Terence J. Hughes Sep 2004

Polar Mm5 Simulations Of The Winter Climate Of The Laurentide Ice Sheet At The Lgm, David H. Bromwich, E. Richard Toracinta, Helin Wei, Robert J. Oglesby, James L. Fastook, Terence J. Hughes

Earth Science Faculty Scholarship

Optimized regional climate simulations are conducted using the Polar MM5, a version of the fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5), with a 60-km horizontal resolution domain over North America during the Last Glacial Maximum (LGM, 21 000 calendar years ago), when much of the continent was covered by the Laurentide Ice Sheet (LIS). The objective is to describe the LGM annual cycle at high spatial resolution with an emphasis on the winter atmospheric circulation. Output from a tailored NCAR Community Climate Model version 3 (CCM3) simulation of the LGM climate is used to provide the initial and lateral boundary …

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Variations In Ice Rafted Detritus On Beaches In The South Shetland Islands: A Possible Climate Proxy, Brenda L. Hall, Ethan R. Perry Sep 2004

Variations In Ice Rafted Detritus On Beaches In The South Shetland Islands: A Possible Climate Proxy, Brenda L. Hall, Ethan R. Perry

Earth Science Faculty Scholarship

Raised beach ridges on Livingston Island of the South Shetland Islands display variations in both quantity and source of ice rafted detritus (IRD) received over time. Whereas the modem beach exhibits little IRD, all of which is of local origin, the next highest beach (similar to250 C-14 yr BP) has large amounts, some of which comes from as far away as the Antarctic Peninsula. Significant quantities of IRD also were deposited similar to 1750 C-14 yr BP. Both time periods coincide with generally cooler regional conditions and, at least in the case of the similar to250 yr old beach, local …

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Sea Level Pressure Variability Over The Southern Indian Ocean Inferred From A Glaciochemical Record In Princess Elizabeth Land, East Antarctica, Cunde Xiao, Paul Andrew Mayewski, Dahe Qin, Zhongqin Li, Mingjun Zhang, Yuping Yan Aug 2004

Sea Level Pressure Variability Over The Southern Indian Ocean Inferred From A Glaciochemical Record In Princess Elizabeth Land, East Antarctica, Cunde Xiao, Paul Andrew Mayewski, Dahe Qin, Zhongqin Li, Mingjun Zhang, Yuping Yan

Earth Science Faculty Scholarship

A 250-year, high-resolution, multivariate ice core record from LGB65 (70degrees50'07"S, 77degrees04'29"E; 1850 m asl), Princess Elizabeth Land (PEL), is used to investigate sea level pressure (SLP) variability over the southern Indian Ocean (SIO). Empirical orthogonal function (EOF) analysis reveals that the first EOF (EOF1) of the glaciochemical record from LGB65 represents most of the variability in sea salt throughout the 250-year record. EOF1 is negatively correlated (95% confidence level and higher) to instrumental mean sea level pressure (MSLP) at Kerguelen and New Amsterdam islands, SIO. On the basis of comparison with NCEP/NCAR reanalysis, strong correlations were found between sea-salt variations …

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El Nino Suppresses Aantarctic Warming, Nancy A.N. Bertler, Peter J. Barrett, Paul Andrew Mayewski, Ryan L. Fogt, Karl J. Kreutz, James Shulmeister Aug 2004

El Nino Suppresses Aantarctic Warming, Nancy A.N. Bertler, Peter J. Barrett, Paul Andrew Mayewski, Ryan L. Fogt, Karl J. Kreutz, James Shulmeister

Earth Science Faculty Scholarship

Here we present new isotope records derived from snow samples from the McMurdo Dry Valleys, Antarctica and re-analysis data of the European Centre for Medium-Range Weather Forecasts (ERA-40) to explain the connection between the warming of the Pacific sector of the Southern Ocean [Jacka and Budd, 1998; Jacobs et al., 2002] and the current cooling of the terrestrial Ross Sea region [Doran et al., 2002a]. Our analysis confirms previous findings that the warming is linked to the El Nino Southern Oscillation (ENSO) [Kwok and Comiso, 2002a, 2002b; Carleton, 2003; Ribera and Mann, 2003; Turner, 2004], and provides new evidence that …

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Deglacial Chronology Of The Northern Scott Coast From Relative Sea-Level Curves, Brenda Hall Aug 2004

Deglacial Chronology Of The Northern Scott Coast From Relative Sea-Level Curves, Brenda Hall

University of Maine Office of Research Administration: Grant Reports

This award provides support for three years for a project to develop a radiocarbon chronology for recession of grounded ice from the northwestern Ross Sea Embayment (northern Scott Coast) since the Last Glacial Maximum (LGM). A key unresolved question in Antarctic glaciology concerns the stability of the marine-based West Antarctic ice sheet (WAIS). One way to gain insight into present and future stability is to examine its past behavior. In particular, the timing of deglaciation from the LGM position on the continental shelf is critical for isolating the mechanisms (sea level, climate, ocean temperature, and internal dynamics) that control WAIS …

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A Record Of Atmospheric Co2 During The Last 40,000 Years From The Siple Dome, Antarctica Ice Core, Jinho Ahn, Martin Wahlen, Bruce L. Deck, Ed J. Brook, Paul Andrew Mayewski, Kendrick C. Taylor, James W.C. White Jul 2004

A Record Of Atmospheric Co2 During The Last 40,000 Years From The Siple Dome, Antarctica Ice Core, Jinho Ahn, Martin Wahlen, Bruce L. Deck, Ed J. Brook, Paul Andrew Mayewski, Kendrick C. Taylor, James W.C. White

Earth Science Faculty Scholarship

We have measured the CO2 concentration of air occluded during the last 40,000 years in the deep Siple Dome A ( hereafter Siple Dome) ice core, Antarctica. The general trend of CO2 concentration from Siple Dome ice follows the temperature inferred from the isotopic composition of the ice and is mostly in agreement with other Antarctic ice core CO2 records. CO2 rose initially at similar to 17.5 kyr B. P. ( thousand years before 1950), decreased slowly during the Antarctic Cold Reversal, rose during the Younger Dryas, fell to a local minimum at around 8 kyr B. P., and rose …

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Beryllium In Antarctic Ultrahigh-Temperature Granulite-Facies Rocks And Its Role In Partial Melting Of The Lower Continental Crust, Edward S. Grew Jun 2004

Beryllium In Antarctic Ultrahigh-Temperature Granulite-Facies Rocks And Its Role In Partial Melting Of The Lower Continental Crust, Edward S. Grew

University of Maine Office of Research Administration: Grant Reports

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to investigate the role of beryllium in lower crustal partial melting events. The formation of granitic liquids by partial melting deep in the Earth's crust is one of the major topics of research in igneous and metamorphic petrology today. One aspect of this sphere of research is the beginning of the process, specifically, the geochemical interaction between melts and source rocks before the melt has left the source area. One example of anatexis in metamorphic rocks affected by conditions found deep …

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Self-Assembly Of Inorganic Membranes: Attachment Of Gold Nanoparticles To A Mesoporous Silica Membrane, Jennifer K. Saucier May 2004

Self-Assembly Of Inorganic Membranes: Attachment Of Gold Nanoparticles To A Mesoporous Silica Membrane, Jennifer K. Saucier

Honors College

The purpose of this study was to investigate the self-assembly of gold nanoparticles to create thin, densely packed structures several monolayers thick for the synthesis of a membrane. Silica membrane synthesis was examined as a support for deposition of the nanoparticles. Pore size formation and thickness were controlled to promote high flux, defect free layer formation while providing for optimum separation. Silica mesoporous membranes were created through the acid-catalyzed hydrolysis of tetraethyl orthosilicate. An ionic block co-polymer was used to control a networked pore formation. The silica sols were dip coated on macroporous alumina supports. The silica membranes were characterized …

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Collaborative Research: Locating The Mantle Component In Granite, Daniel R. Lux, John P. Hogan, David Gibson Apr 2004

Collaborative Research: Locating The Mantle Component In Granite, Daniel R. Lux, John P. Hogan, David Gibson

University of Maine Office of Research Administration: Grant Reports

Granitic plutons of the Coastal Maine Magmatic Province (CMMP) commonly display dramatic field relations that record interaction between magmas of markedly different composition (chemical and isotopic) and physical properties. Silicic magma chambers, derived from the crust, received influxes of denser mafic magma that spread out along the floor of these chambers to produce a compositional stratification know as Mafic and Silicic Layered Intrusions (MASLI). The spectacular field relations and large compositional variation in the vicinity of the interface between contrasting magma types are well document by recent studies. In contrast, the extent of physical and chemical coupling between the base …

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Acquisition Of Digitial Geophysical Equipment For University Of Maine Sea-Level, Coastal And Lacustrine Research, Daniel Belknap, Joseph Kelley Apr 2004

Acquisition Of Digitial Geophysical Equipment For University Of Maine Sea-Level, Coastal And Lacustrine Research, Daniel Belknap, Joseph Kelley

University of Maine Office of Research Administration: Grant Reports

This Major Research Instrumentation award to University of Maine provides geophysical instrumentation for study of sea level and related coastal research. Consisting of a side-scan sonar system, seismic reflection profiler, digital data processing system and a vibracorer, it will be particularly used for research into evolution of coastal and nearshore systems and climate change in glaciomarine environments, especially the Gulf of Maine and adjacent environs. Research plans by University of Maine faculty and students will focus on the acquisition of data needed to model processes of change near former ice sheet margins. The facility plans to build on research partnerships …

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Association Between Atmospheric Circulation Patterns And Firn-Ice Core Records From The Inilchek Glacierized Area, Central Tien Shan, Asia, Vladimir B. Aizen, Elena M. Aizen, John M. Melack, Karl J. Kreutz, L. Dewayne Cecil Apr 2004

Association Between Atmospheric Circulation Patterns And Firn-Ice Core Records From The Inilchek Glacierized Area, Central Tien Shan, Asia, Vladimir B. Aizen, Elena M. Aizen, John M. Melack, Karl J. Kreutz, L. Dewayne Cecil

Earth Science Faculty Scholarship

Glacioclimatological research in the central Tien Shan was performed in the summers of 1998 and 1999 on the South Inilchek Glacier at 5100 - 5460 m. A 14.36 m firn-ice core and snow samples were collected and used for stratigraphic, isotopic, and chemical analyses. The firn-ice core and snow records were related to snow pit measurements at an event scale and to meteorological data and synoptic indices of atmospheric circulation at annual and seasonal scales. Linear relationships between the seasonal air temperature and seasonal isotopic composition in accumulated precipitation were established. Changes in the delta(18)O air temperature relationship, in major …

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Impact Of Preindustrial Biomass-Burning Emissions On The Oxidation Pathways Of Tropospheric Sulfur And Nitrogen, B. Alexander, J. Savarino, Karl J. Kreutz, M. H. Thiemens Apr 2004

Impact Of Preindustrial Biomass-Burning Emissions On The Oxidation Pathways Of Tropospheric Sulfur And Nitrogen, B. Alexander, J. Savarino, Karl J. Kreutz, M. H. Thiemens

Earth Science Faculty Scholarship

Ice core measurements (H2O2 and CH4/HCHO) and modeling studies indicate a change in the oxidation capacity of the atmosphere since the onset of the Industrial Revolution due to increases in fossil fuel burning emissions [e. g., Lelieveld et al., 2002; Hauglustaine and Brasseur, 2001; Wang and Jacob, 1998; Staffelbach et al., 1991]. The mass-independent fractionation (MIF) in the oxygen isotopes of sulfate and nitrate from a Greenland ice core reveal that biomass-burning events in North America just prior to the Industrial Revolution significantly impacted the oxidation pathways of sulfur and nitrogen species deposited in Greenland ice. This finding highlights the …

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Expansion And Renovation Of The Darling Marine Center Library, Kevin Eckelbarger Mar 2004

Expansion And Renovation Of The Darling Marine Center Library, Kevin Eckelbarger

University of Maine Office of Research Administration: Grant Reports

This award provides partial funding for expansion and modernization of the library at The Darling Marine Center. The library currently contains more marine-related holdings than any other library in Maine, and is an important resource for researchers and students interested in the biology of the Gulf of Maine and the Maine coast. Because of current space limitations, a third of the library's holdings are stored in other buildings and attic spaces. The library is not wheelchair accessible, has no significant study space, and provides only limited access to electronic databases. The proposed changes include: 1) construction of a 1,500 sq. …

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Collaborative Research: Southern Andes Paleoclimate; A Testof Abrupt Ocean-Atmosphere Reorganizations In Glacial Cycle, George Denton Feb 2004

Collaborative Research: Southern Andes Paleoclimate; A Testof Abrupt Ocean-Atmosphere Reorganizations In Glacial Cycle, George Denton

University of Maine Office of Research Administration: Grant Reports

In the late 1980s, Broecker and Denton prepared papers on the concept that glacial-to-interglacial transitions involved global reorganizations of the ocean-atmosphere system (Broecker, W. S. and Denton, G. H., 1989. The role of ocean-atmosphere reorganizations in glacial cycles. Geochimica et Cosmochimica Acta, 53, 2465-2501; Broecker, W. S. and Denton, G. H., 1990, What drives glacial cycles? Sci. American, 262, 49-56). These reorganizations were thought to constitute jumps of Earth's climate systems between stable modes of operation, and they featured changes in the greenhouse-gas content or reflectivity of the atmosphere. In that concept, switches in thermohaline circulation, resulting from changes in …

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Millenial-Scale Climatic Oscillations In New Zealand During The Last Glacial Cycle; Pep Iii Transect, George H. Denton Feb 2004

Millenial-Scale Climatic Oscillations In New Zealand During The Last Glacial Cycle; Pep Iii Transect, George H. Denton

University of Maine Office of Research Administration: Grant Reports

Millennial-Scale Climatic Oscillations in New Zealand During the Last Glacial Cycle: PEP III Transect Paleoclimate records from Greenland ice cores and North Atlantic sediments indicate that the glacial climate over the North Atlantic basin was punctuated with large and frequent abrupt climatic changes (Dansgaard-Oeschger and Henrich events). Because the events first appeared to have been regionally restricted, most explanations have invoked regional forcing mechanisms. But quite a different perspective would emerge if these events were shown to be of this global-scale. SGER award supports a reconnaissance study of the glacial and vegetative paleoclimate record of the massive morainal deposits of …

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U.S. Graduate Student Travel To The Second Agentlink European Agent Systems Summer School (Easss) 2000, Thomas A. Wagner Feb 2004

U.S. Graduate Student Travel To The Second Agentlink European Agent Systems Summer School (Easss) 2000, Thomas A. Wagner

University of Maine Office of Research Administration: Grant Reports

This award supports international travel for fifteen U.S. graduate students who would not otherwise be able to attend the Second AgentLink European Agent Systems Summer School being held in Saarbrucken, Germany, from August 14-18, 2000. AgentLink, Europe's ESPRIT-funded Network of Excellence for agent-based computing, organizes the school (http://www.agentlink.org). It is a world-class event that will bring together internationally recognized researchers in the area of autonomous agents and multi-agent systems to present introductory and advanced courses in the theoretical and practical aspects of agent-based computing. The objective of this award is to encourage and enable U.S. graduate students of outstanding merit …

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Catastrophic Ice Shelf Breakup As The Source Of Heinrich Event Icebergs, Christina L. Hulbe, Douglas R. Macayeal, George H. Denton, Johan Kleman, Thomas V. Lowell Jan 2004

Catastrophic Ice Shelf Breakup As The Source Of Heinrich Event Icebergs, Christina L. Hulbe, Douglas R. Macayeal, George H. Denton, Johan Kleman, Thomas V. Lowell

Earth Science Faculty Scholarship

Heinrich layers of the glacial North Atlantic record abrupt widespread iceberg rafting of detrital carbonate and other lithic material at the extreme-cold culminations of Bond climate cycles. Both internal (glaciologic) and external ( climate) forcings have been proposed. Here we suggest an explanation for the iceberg release that encompasses external climate forcing on the basis of a new glaciological process recently witnessed along the Antarctic Peninsula: rapid disintegrations of fringing ice shelves induced by climate-controlled meltwater infilling of surface crevasses. We postulate that peripheral ice shelves, formed along the eastern Canadian seaboard during extreme cold conditions, would be vulnerable to …

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Development Of A Fourier Transform-Based Time-Of-Flight Electron Spectrometer With Ultra-High Resolution, Brian Frederick, Peter H. Kleban Jan 2004

Development Of A Fourier Transform-Based Time-Of-Flight Electron Spectrometer With Ultra-High Resolution, Brian Frederick, Peter H. Kleban

University of Maine Office of Research Administration: Grant Reports

This project, funded by the Major Research Instrumentation program, will develop a time-of-flight electron velocity analyzer using advanced modulation and Fourier deconvolution techniques with a throughput advantage on the order of 1000 over existing instruments. The new spectrometer will operate with ultra-high resolution in the energy range 1-1000 electron volts. It will be useful for the investigation of surface properties under ultra-high vacuum and a variety of other scientific and commercial applications. The device utilizes secondary chopping of the electron beam in the nanosecond or sub-nanosecond time regime, and state-of-the-art Fourier transform-based digital signal recovery methods. Additionally, there is potential …

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Magmatic To Solid-State Fabric Transition In A Post-Tectonic Tonalite Pluton, Scott E. Johnson Jan 2004

Magmatic To Solid-State Fabric Transition In A Post-Tectonic Tonalite Pluton, Scott E. Johnson

University of Maine Office of Research Administration: Grant Reports

Magma chambers are an essential component in the construction of oceanic and continental lithosphere, and profoundly influence the thermal and mechanical behavior of the crust and mantle. The mechanical properties of a magma chamber change during cooling and crystallization, as accommodation of deformation changes from magmatic flow to solid-state processes. Thus, to understand the thermo-mechanical evolution of magma chambers, it is crucial to understand the relative importance of magmatic and solid-state flow, and the nature of the transition between them. This project is investigating such a transition preserved in the San Jose pluton, Baja California, Mexico. The pluton postdates the …

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Surface Deformations As Indicators Of Deep Ebullition Fluxes In A Large Northern Peatland, P. H. Glaser, J. P. Chanton, P. Morin, D. O. Rosenberry, D. I. Siegel, O. Ruud, L. I. Chasar, Andrew S. Reeve Jan 2004

Surface Deformations As Indicators Of Deep Ebullition Fluxes In A Large Northern Peatland, P. H. Glaser, J. P. Chanton, P. Morin, D. O. Rosenberry, D. I. Siegel, O. Ruud, L. I. Chasar, Andrew S. Reeve

Earth Science Faculty Scholarship

Peatlands deform elastically during precipitation cycles by small (+/- 3 cm) oscillations in surface elevation. In contrast, we used a Global Positioning System network to measure larger oscillations that exceeded 20 cm over periods of 4 - 12 hours during two seasonal droughts at a bog and fen site in northern Minnesota. The second summer drought also triggered 19 depressuring cycles in an overpressured stratum under the bog site. The synchronicity between the largest surface deformations and the depressuring cycles indicates that both phenomena are produced by the episodic release of large volumes of gas from deep semi-elastic compartments confined …

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Dating The Siple Dome (Antarctica) Ice Core By Manual And Computer Interpretation Of Annual Layering, Kendrick C. Taylor, Richard B. Alley, Debra A. Meese, Matthew K. Spencer, Ed J. Brook, Nelia W. Dunbar, Robert C. Finkel, Anthony J. Gow, Andrei V. Kurbatov, Gregg W. Lamorey, Paul Andrew Mayewski, Eric A. Meyerson, Kunihiko Nishiizumi, Gregory A. Zielinski Jan 2004

Dating The Siple Dome (Antarctica) Ice Core By Manual And Computer Interpretation Of Annual Layering, Kendrick C. Taylor, Richard B. Alley, Debra A. Meese, Matthew K. Spencer, Ed J. Brook, Nelia W. Dunbar, Robert C. Finkel, Anthony J. Gow, Andrei V. Kurbatov, Gregg W. Lamorey, Paul Andrew Mayewski, Eric A. Meyerson, Kunihiko Nishiizumi, Gregory A. Zielinski

Earth Science Faculty Scholarship

The Holocene portion of the Siple Dome (Antarctica) ice core was dated by interpreting the electrical, visual and chemical properties of the core. The data were interpreted manually and with a computer algorithm. The algorithm interpretation was adjusted to be consistent with atmospheric methane stratigraphic ties to the GISP2 (Greenland Ice Sheet Project 2) ice core, (BE)-B-10 stratigraphic ties to the dendrochronology C-14 record and the dated volcanic stratigraphy. The algorithm interpretation is more consistent and better quantified than the tedious and subjective manual interpretation.

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Ice Dynamics Preceding Catastrophic Disintegration Of The Floating Part Of Jakobshavn Isbrie, Greenland, Jesse V. Johnson, Paul R. Prescott, Terence J. Hughes Jan 2004

Ice Dynamics Preceding Catastrophic Disintegration Of The Floating Part Of Jakobshavn Isbrie, Greenland, Jesse V. Johnson, Paul R. Prescott, Terence J. Hughes

Earth Science Faculty Scholarship

The floating terminal of Jakobshavn Isbr ae, the fastest Greenland ice stream, has disintegrated since 2002, resulting in a doubling of ice velocity and rapidly lowering inland ice elevations. Conditions prior to disintegration were modeled using control theory in a plane-stress solution, and the Missoula model of ice-shelf flow. Both approaches pointed to a mechanism that inhibits ice flow and that is not captured by either approach. Jamming of flow, an inherent property of granular materials passing through a constriction (Jakobshavn Isfjord), is postulated as the mechanism. Rapid disintegration of heavily crevassed floating ice accompanies break-up of the ice jam.

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A 200 Year Sub-Annual Record Of Sulfate In West Antarctica, From Sixteen Ice Cores, D. Dixon, Paul Andrew Mayewski, S. Kaspari, Sharon B. Sneed, M. Handley Jan 2004

A 200 Year Sub-Annual Record Of Sulfate In West Antarctica, From Sixteen Ice Cores, D. Dixon, Paul Andrew Mayewski, S. Kaspari, Sharon B. Sneed, M. Handley

Earth Science Faculty Scholarship

Sixteen high-resolution ice-core records from West Antarctica and South Pole are used to examine the spatial and temporal distribution of sulfate for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than 1 year based on known global-scale volcanic events. A dual transport source for West Antarctic sea-salt (ss) SO42- and excess (xs) SO42- is observed: lower-tropospheric for areas below 1000m elevation and mid-/upper-tropospheric/stratospheric for areas located above 1000m. Our XsSO(4)(2-) records with volcanic peaks removed do not display any evidence of an anthropogenic impact on West …

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A 700 Year Record Of Southern Hemisphere Extratropical Climate Variability, Paul Andrew Mayewski, Kirk A. Maasch, J W.C. White, E. J. Steig, E. Meyerson, I. Goodwin, V. I. Morgan, T. Van Ommen, M. A.J. Curran, J. Souney, Karl Kreutz Jan 2004

A 700 Year Record Of Southern Hemisphere Extratropical Climate Variability, Paul Andrew Mayewski, Kirk A. Maasch, J W.C. White, E. J. Steig, E. Meyerson, I. Goodwin, V. I. Morgan, T. Van Ommen, M. A.J. Curran, J. Souney, Karl Kreutz

Earth Science Faculty Scholarship

Annually dated ice cores from West and East Antarctica provide proxies for past changes in atmospheric circulation over Antarctica and portions of the Southern Ocean, temperature in coastal West and East Antarctica, and the frequency of South Polar penetration of El Nino events. During the period (AD) 1700-1850, atmospheric circulation over the Antarctic and at least portions of the Southern Hemisphere underwent a mode switch departing from the out-of-phase alternation of multi-decadal long phases of EOF1 and EOF2 modes of the 850 hPa field over the Southern Hemisphere (as defined in the recent record by Thompson and Wallace, 2000; Thompson …

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