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Articles 1 - 30 of 445

Full-Text Articles in Glaciology

Giovanni Badino (1953-2017), Arrigo Cigna, Paolo Forti Oct 2017

Giovanni Badino (1953-2017), Arrigo Cigna, Paolo Forti

International Journal of Speleology

Short obituary of Giovanni Badino.


The Geography Of Glaciers And Perennial Snowfields In The American West, Andrew G. Fountain, Bryce Glenn, Hassan J. Basagic Aug 2017

The Geography Of Glaciers And Perennial Snowfields In The American West, Andrew G. Fountain, Bryce Glenn, Hassan J. Basagic

Geology Faculty Publications and Presentations

A comprehensive mid-20th century inventory of glaciers and perennial snowfields (G&PS) was compiled for the American West, west of the 100° meridian. The inventory was derived from U.S. Geological Survey 1:24,000 topographic maps based on aerial photographs acquired during 35 years, 1955–1990, of which the first 20 years or more was a cool period with little glacier change. The mapped features were filtered for those greater than 0.01 km2. Results show that 5036 G&PS (672 km2, 14 km3) populate eight states, of which about 1276 (554 km2, 12 km3) are glaciers. Uncertainty is ...


Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, Sanghyun Lee, Jacqueline E. Reber, Nicholas W. Hayman, Mary F. Wheeler Jun 2017

Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, Sanghyun Lee, Jacqueline E. Reber, Nicholas W. Hayman, Mary F. Wheeler

Jacqueline Reber

Fractures that propagate off of weak slip planes are known as wing cracks and often play important roles in both tectonic deformation and fluid flow across reservoir seals. Previous numerical models have produced the basic kinematics of wing crack openings but generally have not been able to capture fracture geometries seen in nature. Here we present both a phase-field modeling approach and a physical experiment using gelatin for a wing crack formation. By treating the fracture surfaces as diffusive zones instead of as discontinuities, the phase-field model does not require consideration of unpredictable rock properties or stress inhomogeneities around crack ...


Toward The Development Of A 10be Chronology Of Glaciation In The Mosquito Range, Colorado: A Progress Report, Noah Bensen, Keith A. Brugger Apr 2017

Toward The Development Of A 10be Chronology Of Glaciation In The Mosquito Range, Colorado: A Progress Report, Noah Bensen, Keith A. Brugger

Undergraduate Research Symposium 2017

The Last Glacial Maximum (LGM) in the Rocky Mountain region occurred about 21 ka (20,000 years before present). However, dated glacial chronologies suggest that while LGM glacier advances in individual ranges in Colorado were somewhat synchronous, retreat from their maximum extents was asynchronous, varying between ~20 and 15 ka or later. The precise timing and spatial variation of glacier advance and retreat provides insights into LGM climate change and is necessary to calibrate climate models. To better understand the timing of the LGM in the Mosquito Range in Colorado, we collected 12 samples from granitic boulders on moraine crests ...


Gravity And Passive Seismic Methods Used Jointly For Understanding The Subsurface In A Glaciated Terrain: Dowling And Maple Grove Quadrangles, Barry County, Michigan, Scott A. Feldpausch Apr 2017

Gravity And Passive Seismic Methods Used Jointly For Understanding The Subsurface In A Glaciated Terrain: Dowling And Maple Grove Quadrangles, Barry County, Michigan, Scott A. Feldpausch

Master's Theses

The Horizontal to Vertical Spectral Ratio (HVSR) passive, single sensor seismic technique has been used together with gravimetry to study the topography hidden below the glacial drift of two 7.5’ quadrangles in Barry Co., MI. 265 stations were observed with both instruments along roads at nominal spacings of about 0.4 to 0.8 km. Occasional water wells and oil wells with documented penetrations of the base of glacial were used to calibrate the local power law regression calibration. This was also compared with the statewide calibration curve previously established. Results are presented as maps of Simple Bouguer Anomaly ...


Assessing Seasonal And Spatial Variability In The Hydrogeochemistry Of Glacial Meltwater In Iceland, Anisha Tuladhar Apr 2017

Assessing Seasonal And Spatial Variability In The Hydrogeochemistry Of Glacial Meltwater In Iceland, Anisha Tuladhar

Masters Theses & Specialist Projects

A detailed comparative geochemical characterization of three different types of Iceland glacial systems was conducted during June, August, and October, 2016. The study was carried out at a total of 11 outlet glacier rivers flowing from the icecaps Vatnajökull, Eyjafjallajökull, and Mýrdalsjökull. A total of 75 grab samples were collected (25 for each sampling period). The hydrogeochemical variations of Icelandic glacial meltwater are influenced by volcanic activity, temporal changes, and geographical location, which differed between the sampling sites within the glaciers and icecaps. Lower pH range, and comparatively higher and variable specific conductivity, SO4, S and F is linked to ...


Analyzing Glacier Surface Motion Using Lidar Data, Jennifer W. Tellig, Craig Glennie, Andrew G. Fountain, David C. Finnegan Mar 2017

Analyzing Glacier Surface Motion Using Lidar Data, Jennifer W. Tellig, Craig Glennie, Andrew G. Fountain, David C. Finnegan

Geology Faculty Publications and Presentations

Understanding glacier motion is key to understanding how glaciers are growing, shrinking, and responding to changing environmental conditions. In situ observations are often difficult to collect and offer an analysis of glacier surface motion only at a few discrete points. Using light detection and ranging (LiDAR) data collected from surveys over six glaciers in Greenland and Antarctica, particle image velocimetry (PIV) was applied to temporally-spaced point clouds to detect and measure surface motion. The type and distribution of surface features, surface roughness, and spatial and temporal resolution of the data were all found to be important factors, which limited the ...


Utilizing Remote And Numerical Methods To Provide Constraints For The Seasonal Development And Topographic Profiles Of Rock Glaciers, Brett Oliver Jan 2017

Utilizing Remote And Numerical Methods To Provide Constraints For The Seasonal Development And Topographic Profiles Of Rock Glaciers, Brett Oliver

Undergraduate Honors Theses

Rock glaciers represent the dynamic interaction between rock and ice in many alpine settings that lie below the Equilibrium Line Altitude (ELA). These periglacial systems are formed by avalanched snow and debris from an overlying headwall, and are adorned with distinct topographic lobes collectively known as rumples. The central rock glacier of Mount Sopris presents a clear expression of rumples, where the structures are well-defined throughout the 1.8 km long glacier. In addition to clearly-expressed rumples, the accumulation area is constrained to a narrow bowl at the base of the headwall that is easy to identify. To inform our ...


Hall Basin And The Petermann Glacier, Nw Greenland: A Late Quaternary Provenance Glacial History, Blythe Befus Jan 2017

Hall Basin And The Petermann Glacier, Nw Greenland: A Late Quaternary Provenance Glacial History, Blythe Befus

Undergraduate Honors Theses

The Petermann Ice Tongue, located in the northwest region of Greenland, has experienced large caving events since 2010. It is one of the few remaining ice tongues and or ice shelves still present in Greenland. The Petermann Glacier and its ice tongue are important to study as little is known about their glacial history since the deglaciation that likely began in the early Holocene. Through analyzing two cores, 18GC in Hall Basin and 003TC/41GC/003PC in the Petermann Fjord, in conjunction with prior analysis of the HLY03-05GC core in Hall Basin (Jennings et al., 2011), a relative glacial history ...


Teleconnections In Steam: Antarctic Field-Camp Art, Craig Stevens, Gabby O'Connor Nov 2016

Teleconnections In Steam: Antarctic Field-Camp Art, Craig Stevens, Gabby O'Connor

The STEAM Journal

We describe a component of a multi-element STEAM collaboration looking to explore ideas around the life cycle of Antarctic sea ice. One of the intermediate phases of the work involved the scientist deploying partially pre-made art components. Results were modulated by weather and operational constraints and generated a sequence of images and recordings as well as greater understanding of the creative collaboration process.


Glacial Landscape Evolution By Subglacial Quarrying: A Multiscale Computational Approach, Sofie V. Ugelvig, David L. Egholm, Neal R. Iverson Nov 2016

Glacial Landscape Evolution By Subglacial Quarrying: A Multiscale Computational Approach, Sofie V. Ugelvig, David L. Egholm, Neal R. Iverson

Geological and Atmospheric Sciences Publications

Quarrying of bedrock is a primary agent of subglacial erosion. Although the mechanical theory behind the process has been studied for decades, it has proven difficult to formulate the governing principles so that large-scale landscape evolution models can be used to integrate erosion over time. The existing mechanical theory thus stands largely untested in its ability to explain postglacial topography. In this study we relate the physics of quarrying to long-term landscape evolution with a multiscale approach that connects meter-scale cavities to kilometer-scale glacial landscapes. By averaging the quarrying rate across many small-scale bedrock steps, we quantify how regional trends ...


Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. Mckay, John Charles Priscu Oct 2016

Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. Mckay, John Charles Priscu

Geology Faculty Publications and Presentations

A 1-D ice cover model was developed to predict and constrain drivers of long-term ice thick-ness trends in chemically stratified lakes of Taylor Valley, Antarctica. The model is driven by surface ra-diative heat fluxes and heat fluxes from the underlying water column. The model successfully reproduced 16 a (between 1996 and 2012) of ice thickness changes for the west lobe of Lake Bonney (average ice thickness = 3.53 m) and Lake Fryxell (average ice thickness = 4.22 m). Long-term ice thick-ness trends require coupling with the thermal structure of the water column. The heat stored within the temperature maximum of ...


Glaciers In Equilibrium, Mcmurdo Dry Valleys, Antarctica, Andrew G. Fountain, Hassan J. Basagic, Spencer Niebuhr Oct 2016

Glaciers In Equilibrium, Mcmurdo Dry Valleys, Antarctica, Andrew G. Fountain, Hassan J. Basagic, Spencer Niebuhr

Geology Faculty Publications and Presentations

The McMurdo Dry Valleys are a cold, dry polar desert and the alpine glaciers therein exhibit small annual and seasonal mass balances, often


Surficial Geology Of York College Campus (Queens) And Montauk Point (Long Island): An Open Access To Geoscience Education, Nazrul I. Khandaker, Stanley Schleifer, Krishna Mahabir, Erik Menjivar, Ality Aghedo, Dennis Baidoo, Tenzin Choeying, Vanessa Erwin, Jonathan Xavier, Laboni Molla, Akeed Alrubay Sep 2016

Surficial Geology Of York College Campus (Queens) And Montauk Point (Long Island): An Open Access To Geoscience Education, Nazrul I. Khandaker, Stanley Schleifer, Krishna Mahabir, Erik Menjivar, Ality Aghedo, Dennis Baidoo, Tenzin Choeying, Vanessa Erwin, Jonathan Xavier, Laboni Molla, Akeed Alrubay

Publications and Research

To evaluate compositional and textural differences among the samples collected from York College (YC) campus (Queens), Montauk Point (MP) and Hither Hills (HH), Long Island, emphasis is given to the general geologic setting, overall grain size distribution, and relative abundances of light and heavy mineral assemblages. Geologic setting encompasses outwash plains (York College), fluvioglacial and glacial (Montauk Point) and beach and dune complex (Hither Hills). YC samples were collected from depth ranging 40 cm to 250 cm and are mostly an assortment of medium to coarse sand, granule to cobble sized, minor silt, and clay. Presence of low angle cross ...


Montauk Point, An Essential Field Experience For Students In The New York City Area, Stanley Schleifer, Nazrul I. Khandaker, Keshaw Narine Sep 2016

Montauk Point, An Essential Field Experience For Students In The New York City Area, Stanley Schleifer, Nazrul I. Khandaker, Keshaw Narine

Publications and Research

Except for a thin strip of Proterozoic and Paleozoic metamorphic and igneous rock along its very western edge and an outcropping of coastal plain deposits along its northwestern edge, the surface of Long Island is immediately underlain by unconsolidated deposits consisting of moraines of glacial till, outwash plains of stratified drift, and beach and dune complex formed by wave action. Two very prominent features of the island are the Harbor Hill Moraine, which marks the southernmost extent of the last major advance of continental glacier ice in the New York area during the Pleistocene and the Ronkonkoma Moraine, which marks ...


Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, Sanghyun Lee, Jacqueline E. Reber, Nicholas W. Hayman, Mary F. Wheeler Aug 2016

Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, Sanghyun Lee, Jacqueline E. Reber, Nicholas W. Hayman, Mary F. Wheeler

Geological and Atmospheric Sciences Publications

Fractures that propagate off of weak slip planes are known as wing cracks and often play important roles in both tectonic deformation and fluid flow across reservoir seals. Previous numerical models have produced the basic kinematics of wing crack openings but generally have not been able to capture fracture geometries seen in nature. Here we present both a phase-field modeling approach and a physical experiment using gelatin for a wing crack formation. By treating the fracture surfaces as diffusive zones instead of as discontinuities, the phase-field model does not require consideration of unpredictable rock properties or stress inhomogeneities around crack ...


Rate-Weakening Drag During Glacier Sliding, Lucas K. Zoet, Neal R. Iverson Jul 2016

Rate-Weakening Drag During Glacier Sliding, Lucas K. Zoet, Neal R. Iverson

Geological and Atmospheric Sciences Publications

Accurately specifying the relationship between basal drag on a hard, rough glacier bed and sliding speed is a long-standing and central challenge in glaciology. Drag on a rigid bed consisting of steps with linear treads inclined upglacier—a good idealization for the bedrock morphology of some hard-bedded glaciers—has been considered in sliding theories but never studied empirically. Balancing forces parallel to step treads indicates that drag should be independent of sliding speed and cavity size and set by the limit-equilibrium condition sometimes called Iken's bound. In this study we used a large ring-shear device to slide ice at ...


Linking In-Situ Data With Remote Sensing To Analyze Tropical Glacier Stability And Retreat In The Cordillera Blanca, Peru, Chandler H. Santos Jul 2016

Linking In-Situ Data With Remote Sensing To Analyze Tropical Glacier Stability And Retreat In The Cordillera Blanca, Peru, Chandler H. Santos

Masters Theses & Specialist Projects

Glaciers are a major source of freshwater around the world, but they are melting at an increased rate due to atmospheric warming resulting from anthropogenic climate change. In addition to temperature increases, light-absorbing particulates on glaciers also are contributing to glacial melt. This research examines how black carbon, released into the air through partial combustion of biofuels, is affecting the surface albedo of glaciers. I also delineate possible sources of black carbon in the Cordillera Blanca region of Peru. Ground data were collected each year from 2011 to 2013 during the local dry season. Effective black carbon (eBC) values were ...


Trajectory Analysis Of Black Carbon In The Arctic Region, Kimberly Gottschalk Jun 2016

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 HySplit ...


Late Holocene Climate And Environmental Reconstruction Derived From The Asian Ice Core Array (Aica), Bjorn Grigholm May 2016

Late Holocene Climate And Environmental Reconstruction Derived From The Asian Ice Core Array (Aica), Bjorn Grigholm

Electronic Theses and Dissertations

Recent climate change has impacted natural and human systems across the Earth, emphasizing the need for greater understanding of both the existing and changing natural and anthropogenic forcing mechanisms and subsequent responses of the Earth’s climate system. High-resolution, multi-parameter ice core records retrieved and analyzed from two Asian Ice Core Array (AICA) sites, Geladaindong (central Tibetan Plateau) and Inilchek (central Tien Shan) were utilized to reconstruct atmospheric chemical concentrations and composition over the past ~100-500 years, improving the understanding of late Holocene climate and environmental variability in Asia. Both ice cores were analyzed for major and trace elements, major ...


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 Apr 2016

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

Shuang-ye Wu

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 ...


Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu Apr 2016

Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Shuang-ye Wu

Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect ...


Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland Apr 2016

Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland

Allen J. McGrew

New mapping, structural analysis, and 40Ar/39Ar dating reveal an unusually well‐constrained history of Late Eocene extension in the Copper Mountains of the northern Basin and Range province. In this area, the northeast‐trending Copper Creek normal fault juxtaposes a distinctive sequence of metacarbonate and granitoid rocks against a footwall of Upper Precambrian to Lower Cambrian quartzite and phyllite. Correlation of the hanging wall with footwall rocks to the northwest provides an approximate piercing point that requires 8–12 km displacement in an ESE direction. This displaced fault slice is itself bounded above by another normal fault (the Meadow ...


Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar Mar 2016

Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar

Umesh K. Haritashya

Meteorological data collected near the snout of the Gangotri Glacier suggest that the study area receives less rainfall. The average seasonal rainfall is observed to be about 260 mm. The rainfall distribution does not show any monsoon impact. Amount of seasonal rainfall is highly variable (131.4-368.8 mm) from year to year, but, in general, August had the maximum rainfall. A verage daily maximum and minimum temperatures were 14.7 and 4.1°C respectively, whereas average mean temperature was 9.4°C. July was recorded as the warmest month. During daytime, wind speed was four times higher than ...


Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe Mar 2016

Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe

Umesh Haritashya

The Chugach Mountains contain the largest nonpolar alpine glaciers in the world and include a wide variety of glacier types: some are land terminating; some calve variously into tidewater, lakes, and rivers; some are heavily debris covered; some are surge-type, whereas others are neither debris covered nor surge type. Nearly all are retreating, thinning, or both, though some rare ones are advancing, and some are thickening at high elevations. To assist the further documentation of changes, we establish an inventory of glaciers in the eastern Chugach Mountains. Several case studies of diverse glacier types showcase remotesensing applications and are used ...


Iceland: Extreme Learning In The Land Of Fire And Ice, Jason Polk, Leslie North Feb 2016

Iceland: Extreme Learning In The Land Of Fire And Ice, Jason Polk, Leslie North

Leslie North

WKU Libraries kicked off the spring season of "Far Away Places" with Dr. Jason Polk and Dr. Leslie North, Asstant Professors from the Department of Geography and Geology at WKU, who talked about leading a study abroad group to Iceland in the summer of 2015. WKU Libraries kicks off the spring season of Far Away Places with Jason Polk and Leslie North, Asst. Professors from the Department of Geography and Geology at WKU, who will be talking about leading a study abroad group to Iceland in the summer of 2015. Dr. Polk and Dr. North co-taught this course with faculty ...


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 Feb 2016

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 Jan 2016

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 ...


Estimating Supraglacial Lake Depth In West Greenland Using Landsat 8 And Comparison With Other Multispectral Methods, Allen Pope, T A. Scambos, M Moussavi, M Tedesco, M Willis, D Shean, S Grigsby Jan 2016

Estimating Supraglacial Lake Depth In West Greenland Using Landsat 8 And Comparison With Other Multispectral Methods, Allen Pope, T A. Scambos, M Moussavi, M Tedesco, M Willis, D Shean, S Grigsby

University Libraries Open Access Fund Supported Publications

Liquid water stored on the surface of ice sheets and glaciers impacts surface mass balance, ice dynamics, and heat transport. Multispectral remote sensing can be used to detect supraglacial lakes and estimate their depth and area. In this study, we use in situ spectral and bathymetric data to assess lake depth retrieval using the recently launched Landsat 8 Operational Land Imager (OLI). We also extend our analysis to other multispectral sensors to evaluate their performance with similar methods. Digital elevation models derived from WorldView stereo imagery (pre-lake filling and post-drainage) are used to validate spectrally derived depths, combined with a ...


Large Ensemble Modeling Of The Last Deglacial Retreat Of The West Antarctic Ice Sheet: Comparison Of Simple And Advanced Statistical Techniques, David Pollard, Won Chang, Murali Haran, Patrick Applegate, Robert Deconto Jan 2016

Large Ensemble Modeling Of The Last Deglacial Retreat Of The West Antarctic Ice Sheet: Comparison Of Simple And Advanced Statistical Techniques, David Pollard, Won Chang, Murali Haran, Patrick Applegate, Robert Deconto

Geosciences Department Faculty Publication Series

A 3-D hybrid ice-sheet model is applied to the last deglacial retreat of the West Antarctic Ice Sheet over the last  ∼  20 000 yr. A large ensemble of 625 model runs is used to calibrate the model to modern and geologic data, including reconstructed grounding lines, relative sea-level records, elevation–age data and uplift rates, with an aggregate score computed for each run that measures overall model–data misfit. Two types of statistical methods are used to analyze the large-ensemble results: simple averaging weighted by the aggregate score, and more advanced Bayesian techniques involving Gaussian process-based emulation and calibration, and ...