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Articles 1 - 30 of 30
Full-Text Articles in Glaciology
Topographic Control Of Asynchronous Glacial Advances: A Case Study From Annapurna, Nepal, Beth Pratt-Sitaula, Douglas W. Burbank, Arjun M. Heimsath, Neil F. Humphrey, Michael Oskin, Jaakko Putkonen
Topographic Control Of Asynchronous Glacial Advances: A Case Study From Annapurna, Nepal, Beth Pratt-Sitaula, Douglas W. Burbank, Arjun M. Heimsath, Neil F. Humphrey, Michael Oskin, Jaakko Putkonen
All Faculty Scholarship for the College of the Sciences
Differences in the timing of glacial advances, which are commonly attributed to climatic changes, can be due to variations in valley topography. Cosmogenic 10Be dates from 24 glacial moraine boulders in 5 valleys define two age populations, late-glacial and early Holocene. Moraine ages correlate with paleoglacier valley hypsometries. Moraines in valleys with lower maximum altitudes date to the lateglacial, whereas those in valleys with higher maximum altitudes are early Holocene. Two valleys with similar equilibrium-line altitudes (ELAs), but contrasting ages, are < 5 km apart and share the same aspect, such that spatial differences in climate can be excluded. A glacial mass-balance cellular automata model of these two neighboring valleys predicts that change from a cooler-drier to warmer-wetter climate (as at the Holocene onset) would lead to the glacier in the higher altitude catchment advancing, while the lower one retreats or disappears, even though the ELA only shifted by ~120 m.
High-Resolution Study Of Layering Within The Percolation And Soaked Facies Of The Greenland Ice Sheet, Joel Brown, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey, John H. Bradford
High-Resolution Study Of Layering Within The Percolation And Soaked Facies Of The Greenland Ice Sheet, Joel Brown, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey, John H. Bradford
Geosciences Faculty Publications
Within the percolation and soaked facies of the Greenland ice sheet, the relationship between radar-derived internal reflection horizons and the layered structure of the firm column is unclear. We conducted two small-scale ground-penetrating radar (GPR) surveys in conjunction with 10 m firm cores that we colleced within the percolation and soaked facies of the Greenland ice sheet. The two surveys were separated by the distance of about 50 km and about 340 m of elevation leading to about 40 days of difference in the duration of average annual melt. At the higher site (about 1997 ma.s.l.), which receives less melt, …
Flow Dynamics Of An Accumulation Basin: A Case Study Of Upper Kahiltna Glacier, Mount Mckinley, Alaska, Seth Campbell, Karl Kreutz, Erich Osterberg, Steven Arcone
Flow Dynamics Of An Accumulation Basin: A Case Study Of Upper Kahiltna Glacier, Mount Mckinley, Alaska, Seth Campbell, Karl Kreutz, Erich Osterberg, Steven Arcone
Dartmouth Scholarship
We interpreted flow dynamics of the Kahiltna Pass Basin accumulation zone on Mount McKinley, Alaska, USA, using 40, 100 and 900 MHz ground-penetrating radar profiles and GPS surface velocity measurements. We found dipping, englacial surface-conformable strata that experienced vertical thickening as the glacier flowed westward from a steep, higher-velocity (60 m a−1) region into flat terrain associated with a 90° bend in the glacier and lower velocities (15 m a−1) to the south. Stratigraphy near the western side of the basin was surface-conformable to ∼170 m depth and thinned as flow diverged southward, down-glacier. We found complex strata beneath the …
Linkages Between East Antarctic Ice Sheet Extent And Southern Ocean Temperatures Based On A Pliocene High‐Resolution Record Of Ice‐Rafted Debris Off Prydz Bay, East Antarctica, Sandra Passchier
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
[1] Ice‐rafted debris mass accumulation rates (IRD MAR) at a drill site on the Antarctic continental margin are investigated to evaluate the linkages between East Antarctic Ice Sheet extent and Southern Ocean temperatures in the early to mid‐Pliocene. ODP Site 1165 is within 400 km of the Antarctic coastline and in the direct pathway of icebergs released by the Amery Ice Shelf. The Amery Ice Shelf is the largest ice shelf in East Antarctica and it buttresses the Lambert Glacier drainage system, which accounts for 14% of the outflow from the East Antarctic Ice Sheet. IRD MAR were low during …
Geogram 2011, David J. Keeling Editor, Wku Department Of Geography And Geology
Geogram 2011, David J. Keeling Editor, Wku Department Of Geography And Geology
Earth, Environmental, and Atmospheric Sciences Publications
No abstract provided.
Above The Mukpa: The Shifting Ground Of Khumbu's Sacred Geography, Noah Brautigam
Above The Mukpa: The Shifting Ground Of Khumbu's Sacred Geography, Noah Brautigam
Independent Study Project (ISP) Collection
The Himalayan region is suffering from global warming,2 and the effects are felt at all scales, from the local to the global. Himalayan glaciers feed ten major Asian rivers, and 1.3 billion people in southern and southeast Asia reside in those river basins (Eriksson, et al. 2009:1). Global warming is melting these glaciers at a rapid rate, with retreat ranging from 10 to 60 meters per year on average, and many smaller glaciers already disappearing (Mool, Bajracharya and Shrestha 2008:1). This research is a study of local perceptions of global warming and glacial melt among the Sherpas of Khumbu, Nepal. …
Collaborative Research: Microparticle/Tephra Analysis Of The Wais Divide Ice Core, Karl J. Kreutz, Andrei V. Kurbatov, Mark Wells, Paul Andrew Mayewski
Collaborative Research: Microparticle/Tephra Analysis Of The Wais Divide Ice Core, Karl J. Kreutz, Andrei V. Kurbatov, Mark Wells, Paul Andrew Mayewski
University of Maine Office of Research Administration: Grant Reports
This award supports a project to perform continuous microparticle concentration and size distribution measurements (using coulter counter and state-of-the-art laser detector methods), analysis of biologically relevant trace elements associated with microparticles (Fe, Zn, Co, Cd, Cu), and tephra measurements on the WAIS Divide ice core. This initial three-year project includes analysis of ice core spanning the instrumental (~1850-present) to mid- Holocene (~5000 years BP) period, with sample resolution ranging from subannual to decadal. The intellectual merit of the project is that it will help in establishing the relationships among climate, atmospheric aerosols from terrestrial and volcanic sources, ocean biogeochemistry, and …
Melt Regimes, Stratigraphy, Flow Dynamics And Glaciochemistry Of Three Glaciers In The Alaska Range, Seth Campbell, Karl Kreutz, Erich Osterberg, Steven Arcone
Melt Regimes, Stratigraphy, Flow Dynamics And Glaciochemistry Of Three Glaciers In The Alaska Range, Seth Campbell, Karl Kreutz, Erich Osterberg, Steven Arcone
Dartmouth Scholarship
We used ground-penetrating radar (GPR), GPS and glaciochemistry to evaluate melt regimes and ice depths, important variables for mass-balance and ice-volume studies, of Upper Yentna Glacier, Upper Kahiltna Glacier and the Mount Hunter ice divide, Alaska. We show the wet, percolation and dry snow zones located below 2700ma.s.l., at 2700 to 3900ma.s.l. and above 3900ma.s.l., respectively. We successfully imaged glacier ice depths upwards of 480m using 40–100MHz GPR frequencies. This depth is nearly double previous depth measurements reached using mid-frequency GPR systems on temperate glaciers. Few Holocene-length climate records are available in Alaska, hence we also assess stratigraphy and flow …
Using Borehole Logging And Electron Backscatter Diffraction To Orient An Ice Core From Upper Fremont Glacier, Wyoming, Usa, R. W. Obbard, T. Cassano, K. Aho, G. Troderman, I. Baker
Using Borehole Logging And Electron Backscatter Diffraction To Orient An Ice Core From Upper Fremont Glacier, Wyoming, Usa, R. W. Obbard, T. Cassano, K. Aho, G. Troderman, I. Baker
Dartmouth Scholarship
While glacier fabric reflects the accumulated strain, detailed azimuthal information is required to link the microstructure to the flow, and this is not easily gathered at depth. Borehole logging provides a way to obtain a log of azimuthal orientation of tilted stratigraphic features that can be used to orient the core with respect to glacier flow. We demonstrate this using acoustic borehole logs and the ice core from a 162 m borehole in Upper Fremont Glacier, Wind River Range, Wyoming, USA. We measured the dip of tilted dust and bubble layers in the actual ice core, identified them on the …
Ice-Movement History And Kimberlite Indicator Mineral Dispersal Study, Pelly Bay, Lower Boothia Peninsula, And Wager Plateau Areas, Nunavut, Canada, Carl Ozyer
Electronic Thesis and Dissertation Repository
This study reconstructs the ice flow history of the eastern portion of the Keewatin sector of the Laurentide Ice Sheet by integrating field work, remote imagery, and work by others. The study reveals at least seven ice flow phases during the Wisconsinan, including ice streams. A model was developed using inverse distance weighed (IDW) interpolation with GIS to identify and isolate potential kimberlite bedrock sources in kimberlite indicator mineral-rich areas in the Pelly Bay area, Nunavut. Kimberlite indicator mineral (KIM) data were normalized by “peer size” to better understand how KIM grains from three kimberlite sources are distributed within three …
Does The Normal Stress Parallel To The Sliding Plane Affect The Friction Of Ice Upon Ice?, Andrew L. Fortt, Erland M. Schulson
Does The Normal Stress Parallel To The Sliding Plane Affect The Friction Of Ice Upon Ice?, Andrew L. Fortt, Erland M. Schulson
Dartmouth Scholarship
Sliding experiments were performed at –10 degrees C on smooth surfaces of freshwater columnar-grained S2 ice sliding against itself at a velocity of 8X10 –4 ms –1, with the purpose of examining whether normal stress parallel to the sliding plane affects frictional resistance. This component of the stress tensor was varied (0.20–1.83 MPa) using a loading system operated under biaxial compression, by orienting the sliding plane at two different angles, 26 degrees and 64 degrees, with respect to the principal loading direction. Under these conditions, no evidence was found to indicate that the normal stress in the direction of …
Quantifying 20th Century Glacier Change In The Sierra Nevada, California, Andrew G. Fountain, Hassan J. Basagic
Quantifying 20th Century Glacier Change In The Sierra Nevada, California, Andrew G. Fountain, Hassan J. Basagic
Geology Faculty Publications and Presentations
Numerous small alpine glaciers occupy the high elevation regions of the central and southern Sierra Nevada, California. An inventory based on 1:24,000 topographic maps revealed 1719 glaciers and perennial snowfields for a total area of 39.15 +/- 0.13 km(2). The number of 'true' glaciers, versus non-moving ice, is estimated to be 122 covering 14.89 +/- 0.08 km(2) or 38% of the ice-covered area. Historic photographs, geologic evidence, and field mapping were used to determine the magnitude of area change over the past century at 14 glaciers. The area change between 1903 and 2004 ranged from -31% to -78%, averaging -55%. …
An Ice-Core Proxy For Northerly Air Mass Incursions Into West Antarctica, Daniel D. Dixon, Paul Andrew Mayewski, Ian D. Goodwin, Gareth J. Marshall, Rhaelene Freeman, Kirk A. Maasch, Sharon B. Sneed
An Ice-Core Proxy For Northerly Air Mass Incursions Into West Antarctica, Daniel D. Dixon, Paul Andrew Mayewski, Ian D. Goodwin, Gareth J. Marshall, Rhaelene Freeman, Kirk A. Maasch, Sharon B. Sneed
Earth Science Faculty Scholarship
A 200-year proxy for northerly air mass incursions (NAMI) into central and western West Antarctica is developed from the examination of 19 shallow (21–150 m deep) Antarctic ice-core non-sea-salt (nss) Ca2+ concentration records. The NAMI proxy reveals a significant rise in recent decades. This rise is unprecedented for at least the past 200 years and is coincident with anthropogenically driven changes in other large-scale Southern Hemisphere (SH) environmental phenomena such as greenhouse gas (GHG) induced warming, ozone depletion, and the associated intensification of the SH westerlies. The Hysplit trajectory model is used to examine air mass transport pathways into West …
Roosevelt Island Climate Evolution Project (Rice): Us Deep Ice Core Glaciochemistry Contribution (2011- 2014), Paul Andrew Mayewski, Karl J. Kreutz, Andrei V. Kurbatov
Roosevelt Island Climate Evolution Project (Rice): Us Deep Ice Core Glaciochemistry Contribution (2011- 2014), Paul Andrew Mayewski, Karl J. Kreutz, Andrei V. Kurbatov
University of Maine Office of Research Administration: Grant Reports
This award supports a project to analyze a deep ice core which will be drilled by a New Zealand research team at Roosevelt Island. The objectives are to process the ice core at very high resolution to (a) better understand phasing sequences in Arctic/Antarctic abrupt climate change, even at the level of individual storm events; (b) determine the impact of changes in the Westerlies and the Amundsen Sea Low on past/present/future climate change; (c) determine how sea ice extent has varied in the area; (d) compare the response of West Antarctica climate to other regions during glacial/interglacial cycles; and (e) …
Glacimarine Sedimentation Processes At Kronebreen And Kongsvegen, Svalbard, Laura M. Kehrl, Robert L. Hawley, Ross D. Powell, Julie Brigham-Grette
Glacimarine Sedimentation Processes At Kronebreen And Kongsvegen, Svalbard, Laura M. Kehrl, Robert L. Hawley, Ross D. Powell, Julie Brigham-Grette
Dartmouth Scholarship
Tidewater glaciers deposit sediment at their terminus, thereby reducing the relative water depth. Reduced water depth can lead to increased glacier stability through decreased rates of iceberg calving, glacier thinning and submarine melting. Here we investigate sedimentation processes at the termini of Kronebreen and Kongsvegen, Svalbard. We mapped the fjord floor bathymetry in August 2009 and calculate sedimentation rates based on our bathymetry and that from a similar study in 2005. A grounding-line fan is developing near the current position of the subglacial stream. An older, abandoned grounding-line fan that likely formed between ~1987 and 2001 is degrading near the …
An Emerging Technique: Multi-Ice-Core Multi-Parameter Correlations With Antarctic Sea-Ice Extent, Sharon B. Sneed, Paul Andrew Mayewski, Daniel A. Dixon
An Emerging Technique: Multi-Ice-Core Multi-Parameter Correlations With Antarctic Sea-Ice Extent, Sharon B. Sneed, Paul Andrew Mayewski, Daniel A. Dixon
Earth Science Faculty Scholarship
ABSTRACT. Using results stemming from the International Trans-Antarctic Scientific Expedition (ITASE) ice-core array plus data from ice cores from the South Pole and Siple Dome we investigate the use of sodium (Na+), non-sea-salt sulfate (nssSO4 2–) and methylsulfonate (MS–) as proxies for Antarctic sea-ice extent (SIE). Maximum and mean annual chemistry concentrations for these three species correlate significantly with maximum, mean and minimum annual SIE, offering more information and clarification than single ice-core and single species approaches. Significant correlations greater than 90% exist between Na+ and maximum SIE; nssSO4 2– with minimum and mean SIE; and MS– with mean SIE. …
Recent Increase In Black Carbon Concentrations From A Mt. Everest Ice Core Spanning 1860–2000 Ad, S. D. Kaspari, M. Schwikowski, M. Gysel, M. G. Flanner, Kang Shichang, S. Hou, Paul A. Mayewski
Recent Increase In Black Carbon Concentrations From A Mt. Everest Ice Core Spanning 1860–2000 Ad, S. D. Kaspari, M. Schwikowski, M. Gysel, M. G. Flanner, Kang Shichang, S. Hou, Paul A. Mayewski
Climate Change Institute Faculty Scholarship
A Mt. Everest ice core spanning 1860–2000 AD and analyzed at high resolution for black carbon (BC) using a Single Particle Soot Photometer (SP2) demonstrates strong seasonality, with peak concentrations during the winter-spring, and low concentrations during the summer monsoon season. BC concentrations from 1975–2000 relative to 1860–1975 have increased approximately threefold, indicating that BC from anthropogenic sources is being transported to high elevation regions of the Himalaya. The timing of the increase in BC is consistent with BC emission inventory data from South Asia and the Middle East, however since 1990 the ice core BC record does not indicate …
Final Evaluation Report, Sagefox Consulting Group
Final Evaluation Report, Sagefox Consulting Group
IPY STEM Polar Connections
No abstract provided.
Photonic Non-Destructive Measurement Methods For Investigating The Evolution Of Polar Firn And Ice, Daniel James Breton
Photonic Non-Destructive Measurement Methods For Investigating The Evolution Of Polar Firn And Ice, Daniel James Breton
Electronic Theses and Dissertations
When snow falls on glaciers or ice sheets, it persists for many tens, hundreds and sometimes thousands of years before becoming ice. The granular material in between fresh snow and glacial ice is known as firn and is generally 50 to 100 m thick over polar ice sheets. The compaction mechanism of firn into ice (called densification) has important glaciological ramifications in determination of ice sheet stability and related sea level rise effects via remote sensing altimetry. Firn densification is also important for correctly interpreting ice core paleoclimate records, especially those analyzing gases trapped in air bubbles within the glacial …
Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya
Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya
Geology Faculty Publications
The objective of this encyclopedia is to present the current state of scientific understanding of various aspects of earth’s cryosphere – snow, glaciers, ice caps, ice sheets, ice shelves, sea ice, river and lake ice, and permafrost – and their related interdisciplinary connections under one umbrella. Therefore, every effort has been made to provide a comprehensive coverage of cryosphere by including a broad array of topics, such as the atmospheric processes responsible for snow formation; snowfall observations; snow cover and snow surveys; transformation of snow to ice and changes in their properties; classification of ice and glaciers and their worldwide …
Timing, Distribution, Amount, And Style Of Cenozoic Extension In The Northern Great Basin, Christopher D. Henry, Allen J. Mcgrew, Joseph P. Colgan, Arthur W. Snoke, Matthew E. Brueseke
Timing, Distribution, Amount, And Style Of Cenozoic Extension In The Northern Great Basin, Christopher D. Henry, Allen J. Mcgrew, Joseph P. Colgan, Arthur W. Snoke, Matthew E. Brueseke
Geology Faculty Publications
This field trip examines contrasting lines of evidence bearing on the timing and structural style of Cenozoic (and perhaps late Mesozoic) extensional deformation in northeastern Nevada. Studies of metamorphic core complexes in this region report extension beginning in the early Cenozoic or even Late Cretaceous, peaking in the Eocene and Oligocene, and being largely over before the onset of “modern” Basin and Range extension in the middle Miocene. In contrast, studies based on low- temperature thermochronology and geologic mapping of Eocene and Miocene volcanic and sedimentary deposits report only minor, localized extension in the Eocene, no extension at all in …
A Scanning Electron Microscope Technique For Identifying The Mineralogy Of Dust In Ice Cores, Rachel Obbard, Ian Baker, David Prior
A Scanning Electron Microscope Technique For Identifying The Mineralogy Of Dust In Ice Cores, Rachel Obbard, Ian Baker, David Prior
Dartmouth Scholarship
Dust particles in an ice core from East Rongbuk Glacier on the northern slope of Qomolangma (Mount Everest; 28deg 01' N, 58deg 00' E; 6518m a.s.l.), central Himalaya, have been identified as mica using a combination of scanning electron microscope-based techniques and energy-dispersive X-ray spectroscopy to identify the elements present, and electron backscatter diffraction to identify the crystal type. This technique for identifying individual crystalline dust particles in samples of glacial ice could be especially useful in the future for identifying water-soluble crystals in ice, for studying the strain history (glaciotectonics) of basal ice or in studies of icemica composites …
Seasonal Ice Mass-Balance Buoys: Adapting Tools To The Changing Arctic, Chris Polashenski, Don Perovich, Jackie Richter-Menge, Bruce Elder
Seasonal Ice Mass-Balance Buoys: Adapting Tools To The Changing Arctic, Chris Polashenski, Don Perovich, Jackie Richter-Menge, Bruce Elder
Dartmouth Scholarship
Monitoring the local mass balance of Arctic sea ice provides opportunities to attribute the observed changes in a particular floe’s mass balance to specific forcing phenomena. A shift from multi- year to seasonal ice in large portions of the Arctic presents a challenge for the existing Lagrangian array of autonomous ice mass-balance buoys, which were designed with a perennial ice cover in mind. This work identifies the anticipated challenges of operation in seasonal ice and presents a new autonomous buoy designed to monitor ice mass balance in the seasonal ice zone. The new design presented incorporates features which allow the …
Arctic Sea-Ice Melt In 2008 And The Role Of Solar Heating, Donald K. Perovich, Jacqueline A. Richter-Menge, Kathleen F. Jones, Bonnie Light
Arctic Sea-Ice Melt In 2008 And The Role Of Solar Heating, Donald K. Perovich, Jacqueline A. Richter-Menge, Kathleen F. Jones, Bonnie Light
Dartmouth Scholarship
There has been a marked decline in the summer extent of Arctic sea ice over the past few decades. Data from autonomous ice mass-balance buoys can enhance our understanding of this decline. These buoys monitor changes in snow deposition and ablation, ice growth, and ice surface and bottom melt. Results from the summer of 2008 showed considerable large-scale spatial variability in the amount of surface and bottom melt. Small amounts of melting were observed north of Greenland, while melting in the southern Beaufort Sea was quite large. Comparison of net solar heat input to the ice and heat required for …
Microstructural Evolution Of Fine-Grained Layers Through The Firn Column At Summit, Greenland, R. Lomonaco, M. Albert, I. Baker
Microstructural Evolution Of Fine-Grained Layers Through The Firn Column At Summit, Greenland, R. Lomonaco, M. Albert, I. Baker
Dartmouth Scholarship
We present a microstructural characterization of fine-grained layers from the top 90 m of firn from Summit, Greenland, performed using a combination of scanning electron microscopy techniques including secondary electron imaging, energy-dispersive spectroscopy and electron backscattered patterns, and X-ray microcomputed tomography. The impurities in the firn, both soluble impurities and dust particles, were found largely in the grain interiors. Both c- and a-axis pole figures do not show strong evidence of a preferred orientation of the grains even at the bottom of the firn column. The firn structure became increasingly anisotropic with vertical alignment in the top 3 m, probably …
Effect Of A Cold Margin On Ice Flow At The Terminus Of Storglaciaren, Sweden: Implications For Sediment Transfer, Keith A. Brugger, Peter L. Moore, Neal R. Iverson, Denis Cohen, Thomas S. Hooyer, Peter Jansson
Effect Of A Cold Margin On Ice Flow At The Terminus Of Storglaciaren, Sweden: Implications For Sediment Transfer, Keith A. Brugger, Peter L. Moore, Neal R. Iverson, Denis Cohen, Thomas S. Hooyer, Peter Jansson
Geology Publications
The cold-based termini of polythermal glaciers are usually assumed to adhere strongly to an immobile substrate and thereby supply significant resistance to the flow of warm-based ice upglacier. This compressive environment is commonly thought to uplift basal sediment to the surface of the glacier by folding and thrust faulting. We present model and field evidence from the terminus of Storglaciaren, Sweden, showing that the cold margin provides limited resistance to flow from up-glacier. Ice temperatures indicate that basal freezing occurs in this zone at 10−1 –10−2 ma−1, but model results indicate that basal motion at rates …
High Resolution Antarctic Glaciochemical Climate Proxy Records And Their Global Implications, Daniel Arthur Dixon
High Resolution Antarctic Glaciochemical Climate Proxy Records And Their Global Implications, Daniel Arthur Dixon
Electronic Theses and Dissertations
The first section of this study presents major ion, trace element, heavy metal, rare earth element and oxygen isotope data from a series of surface snow samples and shallow firn sections collected along four US ITASE traverses across extensive regions of East and West Antarctica. In each sample the dissolved major ion, total trace element, and d18O concentrations are measured. This provides a baseline from which changes in the chemistry of the atmosphere over Antarctica can be monitored under expected warming scenarios and continued intensification of industrial activities in the Southern Hemisphere. Satellite remote sensing measurements of microwave backscatter and …
Detection Of The Timing And Duration Of Snowmelt In The Hindu Kush-Himalaya Using Quikscat, 2000-2008, Prajjwal K. Panday, Karen E. Frey, Bardan Ghimire
Detection Of The Timing And Duration Of Snowmelt In The Hindu Kush-Himalaya Using Quikscat, 2000-2008, Prajjwal K. Panday, Karen E. Frey, Bardan Ghimire
Geography
The Hindu Kush-Himalayan (HKH) region holds the largest mass of ice in Central Asia and is highly vulnerable to global climate change, experiencing significant warming (0.21 ± 0.08 °C/decade) over the past few decades. Accurate monitoring of the timing and duration of snowmelt across the HKH region is important, as this region is expected to experience further warming in response to increased greenhouse gas forcing. Despite the many advantages and applications of satellite-derived radar scatterometer data shown for capturing ice and snow melt dynamics at high latitudes, similar comprehensive freeze/thaw detection studies at lower latitudes (including the HKH region) are …
Late-Pleistocene Glacial And Climate Fluctuations In The Torres Del Paine Region (51ºs), Southern South America, Juan Luis Garcia
Late-Pleistocene Glacial And Climate Fluctuations In The Torres Del Paine Region (51ºs), Southern South America, Juan Luis Garcia
Electronic Theses and Dissertations
Variations in Earth‘s orbital parameters affect insolation and are thought to drive ice-age cycles (Milankovitch Theory). Northern and southern mid-latitudes show opposing insolation signals, because of the effect of precession. Despite this difference, paleoclimate records from both hemispheres display broadly synchronous glacialinterglacial climate changes tied to northern hemisphere insolation. This would imply that southern hemisphere glaciers advanced in the face of increasing local summer insolation during the last glacial maximum and thus raises questions about the orbital theory of ice ages. Well-dated paleoclimate records are important for testing hypotheses concerning the origin of ice ages, particularly in the southern hemisphere. …
Assessment Of Black Carbon In Snow And Ice From The Tibetan Plateau And Pacific Northwest, Matthew Glen Jenkins
Assessment Of Black Carbon In Snow And Ice From The Tibetan Plateau And Pacific Northwest, Matthew Glen Jenkins
All Master's Theses
An ice core from Mt. Geladandong, Tibetan Plateau, spanning 1853-1983, and snow samples collected over two winters from the Cascade Mountains were analyzed for concentrations of black carbon (BC) using a Single Particle Soot Photometer (SP2). From the ice core, the high-resolution BC record displayed substantial variability, a 2-fold increase in peak concentrations from 1853-1930 to 1930-1983, and a 1.6-fold increase in average concentrations from 1853-1975 to 1975-1983. Concentrations were also higher than at two areas closer to BC sources and analyzed by the same method. In the Pacific Northwest, BC concentrations varied seasonally and annually, with the highest concentrations …