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 56 for “"Atmospheric Composition"”.
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Data assimilation and numerical modelling of atmospheric composition
Atmospheric chemistry and transport models are used for a wide range of applications which include predicting dispersion of a hazardous pollutants, forecasting regional air quality, and modelling global distribution of aerosols and reactive gases. However, any such prediction is uncertain due to …
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Improvements to our Understanding of Toronto-area Atmospheric Composition
… column measurements at the University of Toronto Atmospheric Observatory (TAO), along with data from complementary sources, such as satellites, surface in situ measurements, and nearby rural column measurements, thisthesis aims to improve our understanding of the sources of air pollution and the …
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Sensitivities of Atmospheric Composition to High-Altitude Vehicles Emissions
… transport (SST) emissions. The potential atmospheric impacts of these emissions, including changes in atmospheric composition and air quality, are examined in detail. Previous studies have evaluated global ozone changes and radiative forcing resulting from aviation emissions. However, they …
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Development and Improvement of Spectroscopic Techniques for Atmospheric Composition Measurements from Ground and Space
… a large body of observations and measurements of atmospheric composition. This requires the development of observational techniques and instrumentation, as well as modeling and methods for the correction of past measurements. Some of the more important atmospheric components that contribute …
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Investigating the atmospheric composition and climate response to mitigation: a methane emissions-driven approach
… emissions, to investigate their impact on the atmospheric oxidising capacity and test the hydroxyl (OH) relationship to NOx and CO. The effect of methane on NOx is also explored. Decreased methane emissions perturb both the NO/NO<sub>2</sub> ratio and the partitioning between NOx and reservoir …
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Understanding Middle Atmospheric Composition Variability from the Solar Occultation for Ice Experiment Instrument and Other Datasets
… surrounding the middle atmosphere's chemistry, composition, and dynamics. The middle atmosphere refers to the region from ~ 10 km to ~ 100 km and consists of the Stratosphere, Mesosphere, and Lower Thermosphere. The Stratosphere, Mesosphere, and Thermosphere are bounded by pauses where the …
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Environmental Changes in Eastern Lapland during the last 50 years
… to the current state of the environment, are atmospheric composition and aerosols, meteorology, and biology. The study is based on measurements from Värriö Subarctic Research station for the years 1973 to 2021. Included in atmospheric composition, are the atmospheric anthropogenic gas …
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Cavity Ringdown Spectroscopy in Nitrogen/Oxygen Mixtures in the Presence of Alpha Radiation
… models under development for radiation-induced atmospheric effects. Cavity Ringdown Spectroscopy (CRDS) was used to measure the concentration of chemical products generated as a result of radiation interactions in a controlled atmosphere. Experiments were conducted in a vacuum chamber interfaced …
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Surface-atmosphere coupling on Triton and Pluto.
… distribution of volatile ices, and lower atmospheric structure. My initial studies focused on Triton, which was encountered by Voyager 2 in 1989. One of the surprising results is that Triton's South Polar Cap is considerably larger than predicted by my model. Another basic result is that …
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Ground-based transmission spectroscopy of three inflated Hot Jupiter exoplanets
… This techniques allows for conclusions on the atmospheric composition at the terminator region, the boundary between the day and night side of the planet. Observationally a big challenge, first attempts in the community have been successful in the detection of several absorption features in the …
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Development & Testing of Novel Atmospheric Chemistry Technologies
<p>Atmospheric aerosols play an important role in global atmospheric chemistry and climate and have a detrimental impact on human health. Advancements in measurement technologies allow for better monitoring of atmospheric composition and dynamics, creating better predictive models and understanding …
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Improving the understanding of the influence of emissions of biogenic volatile organic compounds on climate.
… of biogenic volatile organic compounds (BVOCs), atmospheric composition and climate is a key component of the Earth System. However, there remains uncertainty as to its magnitude and sign. An important factor is the gas phase chemistry of BVOCs since this influences atmospheric oxidising capacity …
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An investigation of atmospheric turbulence in the 100-105 km region over Cerro Pachón, Chile
… at higher altitudes, altering middle- and upper-atmospheric composition. Measurements of turbulence activity in the 100-105 km region improve understanding and modeling of atmospheric variability.
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Atmospheric Impacts of Hydrogen as an Aviation Fuel
… overlooked. We quantify the perturbation in the atmospheric composition associated with the introduction of hydrogen-fueled aircraft, broadening the current understanding of the non-CO₂ effects of these fleets. We use the GEOS-Chem High Performance (GCHP) global chemistry-transport model to …
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Study of the Martian upper atmosphere using radio tracking data
… we have learned considerably more about its composition, dynamics and variability. Not only did the new data on global atmospheric densities generate opportunities to understand the atmospheric composition of early Mars and supply constraints at the upper limit of General Circulation Models, …
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Understanding the chemical impacts of biogenic volatile organic compounds and the physical drivers of their observed seasonality
… BVOCs vary widely in their reaction rates with atmospheric oxidants, making their atmospheric impact highly dependent on VOC composition. Their emissions are also dependent on vegetative make up and a number of meteorological and ecological variables. However, the ecological and physical drivers …
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The Observational Diversity of sub-Neptunes
… of these most-common exoplanets with space-based atmospheric spectroscopy, as well as models of their atmospheres including the effects of clouds and hazes. First, I present the near-infrared atmospheric transmission spectrum of the warm Neptune TOI-674 b, observed with the \textit{Hubble} Space …
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Modelling biogeochemical controls on planetary habitability
… planets, but more data on the bulk density and atmospheric composition of newly-discovered exoplanets is required before definitive estimates of their long-term habitability can be made. Exoplanet case studies reveal habitable periods significantly longer than that of the Earth, possibly up to …
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Quantifying future volcanic impacts on climate projections and their uncertainties using stochastic volcanic emissions
… the effects of volcanic eruptions on climate, atmospheric composition, and socio-economic risk assessments.
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