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Moore, David LeeDistributions of fresh water algae, excluding diatomaceae, in northeastern Ohio with reference to glacial history /
Doctor of Philosophy, The Ohio State University, 1976, Graduate School

Committee:

Not Provided (Other)

Subjects:

Biology

Keywords:

Glaciology;Freshwater algae

Dewart, GilbertSeismic investigation of ice properties and bedrock topography at the confluence of two glaciers, Kaskawulsh Glacier, Yukon Territory, Canada /
Doctor of Philosophy, The Ohio State University, 1968, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Keywords:

Glaciers;Glaciology;Ice;Kaskawulsh Glacier ;Seismology

Jeong, SeongsuTime Series Reconstruction of Surface Flow Velocity on Marine-terminating Outlet Glaciers
Doctor of Philosophy, The Ohio State University, 2015, Geodetic Science and Surveying
The flow velocity of glacier and its fluctuation are valuable data to study the contribution of sea level rise of ice sheet by understanding its dynamic structure. Repeat-image feature tracking (RIFT) is a platform-independent, feature tracking-based velocity measurement methodology effective for building a time series of velocity maps from optical images. However, limited availability of perfectly-conditioned images motivated to improve robustness of the algorithm. With this background, we developed an improved RIFT algorithm based on multiple-image multiple-chip algorithm presented in Ahn and Howat (2011). The test results affirm improvement in the new RIFT algorithm in avoiding outlier, and the analysis of the multiple matching results clarified that each individual matching results worked in complementary manner to deduce the correct displacements. LANDSAT 8 is a new satellite in LANDSAT program that has begun its operation since 2013. The improved radiometric performance of OLI aboard the satellite is expected to enable better velocity mapping results than ETM+ aboard LANDSAT 7. However, it was not yet well studied that in what cases the new will sensor will be beneficial, and how much the improvement will be obtained. We carried out a simulation-based comparison between ETM+ and OLI and confirmed OLI outperforms ETM+ especially in low contrast conditions, especially in polar night, translucent cloud covers, and bright upglacier with less texture. We have identified a rift on ice shelf of Pine island glacier located in western Antarctic ice sheet. Unlike the previous events, the evolution of the current started from the center of the ice shelf. In order to analyze this unique event, we utilized the improved RIFT algorithm to its OLI images to retrieve time series of velocity maps. We discovered from the analyses that the part of ice shelf below the rift is changing its speed, and shifting of splashing crevasses on shear margin is migrating to the center of the shelf. Concerning the concurrent disintegration of ice melange on its western part of the terminus, we postulate that change in flow regime attributes to loss of resistance force exerted by the melange. There are several topics that need to be addressed for further improve the RIFT algorithm. As coregistration error is significant contributor to the velocity measurement, a method to mitigate that error needs to be devised. Also, considering that the domain of RIFT product spans not only in space but also in time, its regridding and gap filling work will benefit from extending its domain to both space and time.

Committee:

Ian Howat, Dr. (Advisor); Alper Yilmaz, Dr. (Committee Member); Michael Durand, Dr. (Committee Member)

Subjects:

Climate Change; Earth; Geography; Remote Sensing

Keywords:

glaciology; remote sensing; Greenland; Antarctica; glacier flow; Landsat

Magee, William RobertMagnitude of Extension across the Central Terror Rift, Antarctica: Structural Interpretations and Balanced Cross Sections
Master of Science, The Ohio State University, 2011, Geological Sciences
In Antarctica, where much of the continent is covered by ice, the use of remotely sensed geophysical data is a valuable tool for reconstructing geologic history. Data from the submarine continental shelf are fundamental for determining the structural deformation and geomorphological history of the Antarctic plate. The western Ross Sea contains a segment of the West Antarctic Rift System known as the Terror Rift. The rift lies entirely below sea level and stretches between the two volcanic provinces of Mount Melbourne and Mount Erebus. High-resolution seismic and bathymetry data from the western Ross Sea are used to analyze the structure, kinematics, and deformation history of the Terror Rift. Recent glacial history of the western Ross Sea has also been identified. A revised fault and associated volcanic edifice map of the Terror Rift in the western Ross Sea is provided. The eastern limit of faulting associated with the Terror Rift is redefined by this study. The first balanced cross sections and extension values have been calculated for the Terror Rift. Outcomes of this study provide definite constraint on the magnitude of extension since the onset of rifting in the late Neogene and define the mode of rifting.

Committee:

Terry Wilson (Advisor); E. Scott Bair (Committee Member); Ian Howat (Committee Member)

Subjects:

Geology

Keywords:

seismic interpretation; structural geology; bathymetry; volcanism; glaciology

Wuite, JanSpatial and temporal dynamics of three East Antarctic outlet glaciers and their floating ice tongues
Doctor of Philosophy, The Ohio State University, 2006, Geological Sciences
Observations show that some glaciers in Greenland and Antarctica undergo rapid changes in flow velocity and thickness. There is concern about the implications for global sea levels and ocean circulation. Part of the changes has been ascribed to changes in glacier dynamics. Measuring velocity and velocity gradients are first steps in studying their dynamics and possible response to climatic changes. With the RADARSAT-1 Antarctic Mapping Project (RAMP) a great opportunity arose to derive flow velocity of Antarctica’s glaciers remotely. This study uses RAMP imagery to derive ice flow velocity and, in combination with other datasets, to study spatial and temporal fluctuations in velocity and stress fields of selected Antarctic glaciers. The derived high-resolution surface velocity maps form an important benchmark for gauging possible changes in velocity and dynamics. The maps are derived using pre-established feature tracking techniques that we improved and streamlined in order to extract as much velocity data as possible. To determine important flow governing forces we use force-budget theory. We include a detailed error analysis and investigate the implications of a recently established flow law on derived stresses. The investigations of our study areas suggest that flow has been rather constant over decadal timescales. Based on this we infer that stress fields have not changed significantly either, permitting combinations of various data sets to optimize the velocity field in order to study dynamics in greater detail then previously possible. We find that the relative contribution of side drag declines along the fjords, but demonstrate that, once they leave the valley walls, the glaciers are not immediately free floating ice shelves. Measurements show that ice tongues spread faster in the across flow direction than the along flow direction for a considerable length. In addition there appears to be some lateral drag, once a glacier leaves the coast, which could be associated with sub-surface valley walls or an adjacent ice shelf. This could lead to an increase in along flow creep if the ice tongue were to break off. Finally we conclude that ice tongues are important, because they can provide clues to past ice sheet behavior and fluctuations.

Committee:

Kenneth Jezek (Advisor)

Keywords:

Glaciology; Remote Sensing; Antarctica; Glacier dynamics

Peterson, Donald NeilGlaciological investigations on the Casement Glacier, southeast Alaska /
Doctor of Philosophy, The Ohio State University, 1969, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Keywords:

Glaciers;Casement Glacier ;Glaciology

Dhanasekaran, DeepananthanA Locally Adaptive Spatial Interpolation Technique for the Generation of High-Resolution DEMs
Master of Science, The Ohio State University, 2011, Geodetic Science and Surveying
Airborne traverse data require spatial interpolation to generate continuous Digital Elevation Models (DEMs). DEMs in turn are important resources for geographical and environmental studies. In this study we use ice thickness data and surface elevation data collected by the NASA DC-8 aircraft as a part of the IceBridge mission from October and November, 2009. The ice thickness and surface elevation data downloaded from the National Snow and Ice Data Center (NSIDC) were processed for removal of anomalous data using a GIS. We developed a locally adaptive interpolation algorithm, which segments the data into several local regions based on the statistical properties of the data. We produced ice thickness, surface elevation and subglacial DEMs for Pine Island and Thwaites glaciers using the processed dataset and our locally adaptive algorithm. We made a comparative study between different interpolation techniques to determine the suitable interpolation technique for use with airborne traverse data. Finally, we validated our DEMs through visual comparison with the RADARSAT imageries and by comparison with the existing DEMs available for the Pine Island and Thwaites glaciers. Our DEMs can be used by glaciologists for climate change studies, as it captures the geographic features better than existing DEMs available for this region.

Committee:

Dr. Rongxing Li, PhD (Advisor); Dr. Kenneth C. Jezek, PhD (Committee Member); Dr. Carolyn J. Merry, PhD (Committee Member)

Subjects:

Civil Engineering; Climate Change; Computer Engineering; Earth; Geographic Information Science; Geophysics; Remote Sensing

Keywords:

Mapping; GIS; Geostatistics; Airborne Radar; Lidar; Remote Sensing; Glaciology; Pine Island Glacier; Thwaites Glacier

Higgins, LindseyConstruction and Analysis of an Ice Core-Derived Melt History from West Central Greenland (1765-2006)
Master of Arts, The Ohio State University, 2012, Geography

With global sea level rising and Arctic temperatures increasing more rapidly than any other location on the globe, it is important to understand how surface melting in Greenland today compares with that in the past. A melt history (1765 – 2006 C.E.) has been reconstructed from an ice core collected in 2007 at Crawford Point (69.9°N; 47.0°W, 2022 masl) in west central Greenland. This site lies in the zone of intermittent summer melt and percolation which may result in formation of melt features, thus potentially providing a record of surface warmth. Melt features are primarily bubble free and thus appear clearer and brighter than the surrounding snow, firn, or ice.

This paper presents an efficient and relatively inexpensive technique for quantifying the annual melt percent from an ice core. The Crawford Point core was photographed and high-resolution digital images were used to quantify the extent of melt in each year using a time scale previously constructed by counting seasonal variations in δ18O, complemented by seasonal variations in the concentrations on dust, nitrate, and sulfate. Melt percent was determined using a 1x1 cm grid which was overlain on each year within the core.

Regression analysis was used to determine that melt within the Crawford Point ice core has been increasing at a rate of 0.08% per year, since 1765, and has increased to 0.11% per year after 1900. This record was compared to contemporaneous observations including other melt histories, the existing satellite record, meteorological observations, patterns of atmospheric circulation, other ice core-derived proxy records, and volcanic activity. Regression relationships were employed to examine the correlations between melt at Crawford Point and these other variables.

While melt preserved in ice cores has been previously assessed, there has been no sustained methodology to facilitate comparisons among the resulting records. The results of this study establish the need for standardization of the process used to determine and report melt histories from ice cores. Recommendations are also made regarding future work relating to the extraction of melt histories from Greenland.

Committee:

Ellen Mosley-Thompson, PhD (Advisor); Bryan Mark, PhD (Committee Member); Berry Lyons, PhD (Committee Member); Lonnie Thompson, PhD (Committee Member)

Keywords:

paleoclimate; Greenland; glaciology; global climate change; melt history

Wigmore, Oliver HenryAssessing Spatiotemporal Variability in Glacial Watershed Hydrology: Integrating Unmanned Aerial Vehicles and Field Hydrology, Cordillera Blanca, Peru.
Doctor of Philosophy, The Ohio State University, 2016, Geography
The glaciers of the Cordillera Blanca Peru are rapidly retreating as a result of climate change, altering the timing, quantity and quality of water available to downstream users. Changes in water availability have serious implications for ecosystems, human livelihoods and regional economies. This dissertation investigates spatiotemporal changes in the glacier hydrologic system of the Cordillera Blanca Peru. It includes three major components. First, I develop multispectral unmanned aerial vehicles (UAV) and kite platforms capable of operating at over 5000m in mountain regions. Secondly, I deploy these platforms to investigate processes of glacier change and surface/subsurface hydrology within the glacial valleys of the Cordillera Blanca. Finally, I integrate UAV datasets with traditional field hydrology to improve our understanding of the spatiotemporal variability in soil moisture and its role in moderating groundwater storage within the Cordillera Blanca. I designed and deployed UAVs on multiple missions at over 5000masl in the Cordillera Blanca, Peru. After describing the UAV design in Chapter 2, this dissertation reports on results of four studies that utilise the UAV to address research questions within the region. Chapter 3 comprehensively assesses the accuracy of photogrammetrically derived structure from motion (SfM) digital elevation models (DEMs), by quantitatively and qualitatively comparing the data against surveyed GPS positions and LiDAR DEMs. Finding that accuracy is as good if not superior to low density LiDAR, with the high density SfM point clouds retaining unique surface details. Chapter 4 investigates the dynamics of glacier change over the debris covered Llaca glacier. I document the importance of debris cover and surface features such as ice cliffs in controlling melt rates. Average glacier downwasting is 0.75m over one year but is highly heterogeneous. Ice cliff horizontal recession rates of up to 25m annual were measured illustrating the importance of debris thickness and ice exposure to the evolution of these systems. Only limited horizontal retreat of the glacier tongue was recorded, indicating that simple measurements of changes in aerial extent are inadequate for understanding actual changes in glacier ice quantity. In Chapter 5 I investigate spatial variability in surface soil moisture. By collecting multispectral (visible, near infrared and thermal infrared) imagery and using the temperature vegetation dryness index (TVDI) I generate 50cm pixel resolution estimates of soil moisture for two proglacial wetland/meadow study sites. Surface soil moisture is found to vary markedly over short distances and is negatively impacted by grazing practices. Through inspection of the multispectral UAV imagery I was able to identify surface and subsurface hydrologic pathways including groundwater springs from airborne thermal imagery. Finally in Chapter 6 I integrate the UAV findings with field instrumentation. I investigate spatiotemporal variability in soil moisture and groundwater table storage within the meadows and wetlands of the Cordillera Blanca. Key findings from the three study sites were the high rates of evapotranspiration, and the limited role of water stored in the groundwater table, and as soil moisture, in buffering dry season stream flow. However, the peatland soils were found to have very low bulk densities (~0.15g/cm3), and a high water storage capacity. Reaching 80-90% volumetric water content at saturation. Thus meadow and wetland systems in the Cordillera Blanca may still play an important role in reducing runoff and increasing groundwater recharge during the wet season, which is an important source of dry season stream flow. My results show that UAVs are an ideal method for studying heterogeneous landscapes at high resolution, and are thus highly suited for small scale studies within mountain regions. This dissertation provides a double faceted scientific contribution of both methodological and technological advances in the ways in which UAV's can be used in earth science and high mountain research as well as empirical knowledge regarding the regional hydrology of the Cordillera Blanca and more generally the tropical Andes. Through its focus on water availability this research has important implications for rural livelihoods and long-term hydrologic, energy, economic and development planning in Peru. This research also contributes to the growing field of UAV applications by pushing the engineering boundaries of this technology, opening up a range of future scientific opportunities in other areas.

Committee:

Bryan Mark, PhD (Advisor); Darla Munroe, PhD (Committee Member); Michael Durand, PhD (Committee Member); Liu Desheng, PhD (Committee Member)

Subjects:

Geography; Geomorphology; Hydrologic Sciences; Hydrology; Physical Geography; Remote Sensing; Robotics; Soil Sciences; Technology; Water Resource Management

Keywords:

Peru; glaciers; uav; uas; drone; unmanned aerial vehicle; mapping; soil moisture; Andes; hydrology; Cordillera Blanca; remote sensing; structure from motion; tvdi; mountains; water resources; global climate change; glaciology;

Anderton, Peter W.Structural glaciology of a glacier confluence, Kaskawulsh Glacier, Yukon Territory, Canada /
Doctor of Philosophy, The Ohio State University, 1967, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geology

Keywords:

Glaciology;Glaciers