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 112 for “"high latitudes"”.
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Non-Linear Magnetosphere-Ionosphere Interactions at High Latitudes
… dispersive Alfven waves and the nightside high-latitude ionosphere. Results are presented from a numerical study of small-scale, intense magnetic field-aligned currents observed in the vicinity of the discrete auroral arc by the Magnetosphere-Ionosphere Coupling in the Alfven Resonator …
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Observations and Modelling of Thermospheric Dynamics at High Latitudes
… wind pattern in the lower middle thermosphere at high latitudes over both hemispheres, known as a wind wall, is investigated. Since scarce information is available about this region of the atmosphere, model simulations by the WACCM-X model are employed. Model simulations, along with WINDII …
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Driving Influences of Ionospheric Electrodynamics at Mid- and High-Latitudes
… of ionospheric electrodynamics at mid- and high-latitudes. In Chapter 2, we analyzed an interval on 12 September 2014 which provided a rare opportunity to examine dynamic variations in the dayside convection throat measured by the RISR-N radar as the IMF transitioned from strong By+ to …
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Quantifying biophysical and biogeochemical influence on northern high latitudes greenhouse gases dynamics
… interactions on northern high latitudes (NHLs) greenhouse gases (GHGs) emission in a terrestrial modeling framework. To achieve this objective, I extended and calibrated a land surface model, the Integrated Science Assessment Model (ISAM), to explore how the physical and …
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The impact of urban centers on American goldfinches (Spinus tristis) overwintering at high latitudes
… (n = 297) at urban and rural sites across latitudes in Michigan. The following winter I trapped individuals in urban and rural settings to sample baseline and stress-induced plasma corticosterone (CORT) levels. Analyses revealed no interaction of latitude and urbanization in the winter …
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Incoherent Scatter Radar Observations of Dynamic Ion Composition Changes at High Latitudes during Geomagnetic Storms
… enable studies of ionospheric composition during highly disturbed conditions and are suitable for data collected with short integration times (2-10 minutes). The improved models incorporate the effects of variable scale height, altitude dependent neutral winds (taken from the horizontal wind model …
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Late Jurassic to Early Cretaceous stable isotope and geochemical records from the northern high latitudes: implications for palaeoclimate
… until now being concentrated in mid- to low latitudes, despite it being generally accepted that global climate is defined to a significant degree by prevailing conditions at the poles. Existing data are also often plagued by poor sampling resolutions and dubious diagenetic histories. This …
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Variations Of E-Region Total Electron Content And Electron Density Profiles Over High Latitudes During Winter Solstice 2007 Using Radio Occultation Measurements
… are (1) E-region electron peak density is higher during active days than during quiet days, and (2) during both types of days, higher density values were found at the magnetic latitude of >60o early morning MLT. Prominent E-region features (TEC and electron density) were observed during …
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POPULATION DYNAMICS AND GEOCHEMISTRY OF BENTHIC AND PLANKTONIC FORAMINIFERA TO INTERPRET THE PALEOCEANOGRAPHIC CHANGES ACROSS THE CENOMANIAN-TURONIAN OCEANIC ANOXIC EVENT 2 AT LOW AND HIGH LATITUDES
… document how global changes impacted at low and high latitudes. The stratigraphic sections are Clot Chevalier in the Vocontian Basin (SE France) and Eastbourne in the Anglo-Paris Basin (SE England) at low latitudes and IODP Sites U1513 and U1516 in the Mentelle Basin (SW Australia) at high …
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Improving Global Satellite Precipitation Products Utilizing Machine Learning
… Precipitation Climatology Project; GPCP) in high latitudes (i.e., poleward of 60°S/N). The possibility of mitigating the latency gap of satellite precipitation products through deep-learning-based nowcasting is also investigated in this dissertation.IMERG is the most popular product among GPM …
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Investigation of High Latitude Ionospheric Irregularities utilizing Modeling and GPS Observations
… coupling mechanisms result in high latitude irregularities that are difficult to characterize. Until recently, the polar and auroral irregularities remained largely unexplored. Inadequate infrastructures to deploy and maintain advanced dual frequency Global Navigation Satellite …
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Vertically Propagating Tides in the Martian Atmosphere
… Martian atmosphere is especially large at high altitudes. Certain tides can propagate away from the region of generation in the lower atmosphere and reach the upper atmosphere, where they can achieve significant amplitudes. Such vertically propagating tides constitute one of the primary …
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Thermohaline circulation stability : a box model
… is presented. The model consists of a northern high latitudes box, a tropical box, and a southern high latitudes box, which respectively can be thought as corresponding to the northern, tropical and southern Atlantic ocean. We study how the strength of THC changes when the system undergoes …
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On the meridional heat transport and its partition between the atmosphere and oceans
… to the ability of the ocean to carry heat to high latitudes. These model results, as well as data, are analyzed in the context of earlier work suggesting that the total meridional heat transport should be insensitive to the details of the atmospheric and oceanic circulation. The heat transport …
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Large scale oceanic circulation and fluxes of freshwater, heat, nutrients and oxygen
… the tropical band and a corresponding cooling at high latitudes. The signature of a large-scale average export production is found for nutrients in several temperate regions. Despite the large uncertainties, the production magnitudes are consistent with independent measurements from sediment traps …
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Detecting Methane Anomalies from Satellite Data in the Arctic
… distribution for atmospheric research in the high latitudes. The aim of the thesis is to provide a dataset of anomalies that a domain expert could use as a starting point for research. The method consists of three data processing steps: satellite data binning, anomaly detection and identifying …
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Impacts of climate change on global agricultural land availability
… scenarios, A1B & B1, which represent relatively high and low emission, respectively. Two ensemble methods, Simple Average Method (SAM) and Root Mean Square Error Ensemble Method (RMSEMM), are employed to assemble the regional climate change which attempts to abate the uncertainty involved in …
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Large scale oceanic circulation and fluxes of freshwater, heat, nutrients and oxygen
… the tropical band and a corresponding cooling at high latitudes. The signature of a large-scale average export production is found for nutrients in several temperate regions. Despite the large uncertainties, the production magnitudes are consistent with independent measurements from sediment traps …
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Self sustained thermohaline oscillations and their implications for biogeochemical cycles
… a strong 'thermal mode' induced by cooling at high latitudes and a weak 'haline mode' induced by evaporation at subtropics. The 'haline mode', obtained with enhanced freshwater flux and reduced vertical diffusivity, is inherently unstable, flushed by thermally-driven polar convection every few …
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