Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 60 for “"mid-latitudes"”.
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Multi-Constellation GNSS Scintillation at Mid-Latitudes
… that amplitude scintillation is severe at low latitudes and phase scintillation is severe at high latitudes. Unlike low and high latitude regions, mid-latitude scintillation has not been extensively studied. Further, it has been suggested that mid-latitude scintillation is negligible. The …
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Investigations of the Martian Mid-Latitudes: Implications for Ground Ice
… first examine sublimation of ice from new small mid-latitude craters with freshly exposed ice imaged by the High Resolution Imaging Science Experiment (HiRISE) camera. I discuss the theory of sublimation by free convection and describe a model that improves on the standard version used in the …
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Studies of Atmospheric Ozone and Related Constituents in the Arctic and at Mid-latitudes
Two UV-visible differential absorption spectroscopy (DOAS) ground-based spectrometers (GBSs) were installed at the Polar Environment Atmospheric Research Laboratory (PEARL) in the Canadian High Arctic (80.1o N, 86.4o W). These two instruments have been used to measure stratospheric trace gases …
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Growth rate simulations of instability mechanisms at low and mid-latitudes for explaining equatorial spread F
… of ionospheric instabilities for both low-- and mid--latitude locations. The purpose of the modeling is to provide simulation support for observations of mid--latitude medium--scale traveling ionospheric disturbances (MSTIDs) coupling into equatorial regions and initiating ESF there. It is …
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Studies of Stratospheric and Tropospheric Ozone, NO2, and BrO Using UV-Visible Spectroscopy in the Arctic and at Mid-latitudes
This thesis utilizes UV-visible spectroscopy to develop new datasets, study Arctic and urban atmospheric composition, and validate satellite data products. The primary instruments used here (the Ground-Based Spectrometers, or GBSs) have been taking measurements at the Polar Environment Atmospheric …
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Dynamics of the geomagnetically disturbed ionosphere as measured by GPS receivers and SuperDARN HF radars
… a recurrent region of anomalous enhanced TEC at mid-latitudes over North America and attempt to characterize its frequency of occurrence. Next, we examine the relationship of convection electric fields to the formation of a polar cap tongue of ionization (TOI) from mid-latitude plumes of storm …
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Analysis of Refractive Effects on Mid-Latitude SuperDARN Velocity Measurements
… refractive index values have been determined at mid latitudes using frequency switched SuperDARN plasma convection velocity estimates. Previous works have found a disparity between high latitude SuperDARN plasma convection velocities and those made by other devices. It was noted that the …
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Ion-neutral coupling in the geomagnetically disturbed mid-latitude ionosphere as observed by SuperDARN HF radars and NATION Fabry-Perot Interferometers
… neutral constituents and ionospheric plasma. The mid-latitude thermosphere-ionosphere system is very complex owing to its sensitivity to both the polar and equatorial processes. The mid-latitudes is also a relatively unexplored and less understood region primarily due to the paucity of observing …
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The relationship between coastal oceanographic variability and the spatial distribution of Argyrosomus coronus on the west coast of southern Africa
… in temperate species away from the warming mid latitudes, towards the cooler poles are becoming evident. This study aimed to quantify the effects of these changes (in terms of temperature, dissolved oxygen and salinity) on the spatial distribution of an important inshore commercial, …
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Water circulation within Tomales Bay, California, U.S.A. : a Mediterranean climate estuary
… coast of the United States of America, in the mid-latitudes at 38° 13' 50" N, 122° 58' 30" W, was chosen as the study site for the "Biogeochemical Reactions In Estuaries" (BRIE) project of the "land Margins Ecosystems Research" (LMER) program of the National Science Foundation in the U.S.A. …
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Long-term Background Ozone and Carbon Monoxide Measurements on the Maltese Islands
… as observed at low-altitude stations in the mid latitudes, especially during winter. The seasonal development of ozone shows a maximum of monthly averages of 55.4ppb in April I May and a minimum of 44.lppb in December I January. The latter is about twice as high as that observed on the …
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Oceanic control of the sea ice edge and multiple equilibria in the climate system
… set by the wind forcing, gives rise to preferred latitudes for the sea ice edge, including a stable large ice cap extending into mid-latitudes. I review multiple equilibria in energy balance models (EBMs), and extend the EBM to include explicit ocean heat transport (OHT) and insulating sea ice. I …
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Observations and Modeling Forcing Mechanisms for the Coastal Dynamics of the Upper Gulf of Thailand
… and surface heat fluxes. The impact of the low latitudes (∼13 °N) on the dynamics is tested by comparing the simulations to results obtained when simulations are modified to mid-latitudes (∼45 °N). The model results show that the circulation in the UGOT is strongly affected by the seasonal …
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The effects of volcanic aerosols on mid-latitude ozone recovery
… (SD-WACCM), the impacts of volcanic aerosols on mid-latitude ozone loss are investigated. These results are compared to the ozone column expected recovery from a run of SD-WACCM with no volcanic eruptions in the same period. Particular emphasis is placed on the last decade to investigate how the …
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Physical Controls on Low and Mid-Latitude Marine Primary Productivity
… inhibit marine primary productivity at low and mid latitudes, based on the supposition that increased water column stability will decrease vertical mixing and consequently the upward entrainment of deep nutrients into the euphotic zone. Herein, we examine the local stratification control of …
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Ionospheric Scintillation Prediction, Modeling, and Observation Techniques for the August 2017 Solar Eclipse
… density irregularities in the ionosphere. At mid-latitudes, scintillation is not as common of an occurrence as it is in equatorial or high-altitude regions. One of the theories that this paper looks into is the possibility of the solar eclipse producing an instability in the ionosphere that …
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Flow Characteristics, Setting, and Basal Boundary Condition of North Greenland Outlet Glaciers
… waters responsible for this extend only to mid-latitudes. In this study, the geometric setting and bed condition is therefore investigated to better understand the flow characteristics and dynamics of high-latitude tidewater glaciers in Greenland. New ice thickness measurements are combined …
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Observations and numerical simulations of electrified, medium-scale traveling ionospheric disturbances (MSTIDs) in the nighttime, mid-latitude ionosphere
… The instabilities typically occur at night near mid-latitudes and are electrified. The polarization electric fields within the structure cause the displacement of electron density to form under an unstable configuration. Previous work on MSTIDs has provided the groundwork for the current study of …
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Crustal History Indicators on Mercury
… with the illumination azimuth (east-west at low-mid latitudes) would be likely to be underrepresented in the global population. Using shaded-relief models with alternative artificial illumination to complete resurveys, I found that my global survey of basinedge scarps has been affected. …
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Case Studies of Stratospheric Nitrogen, Chlorine and Iodine Photochemistry Based on Balloon Borne UV/visible and IR Absorption Spectroscopy
… the budget of stratospheric iodine in high- and mid-latitudes and extend the data base to tropical latitudes. Given the measured IO and OIO upper limits, model calculations show that total gaseous iodine in the lower tropical stratosphere is less abundant than (0.32 ± 0.11) ppt or (0.38 ± 0.10) …
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