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 36 for “"GEOS-Chem"”.
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Investigating the effect of variability in biomass burning emissions inventories on GEOS-Chem modeled trace gas and aerosol concentrations
… the vegetative fuels burned. Using the GEOS-Chem v1 1-01 chemical transport model, we studied how differences in emissions estimates between two commonly-used global biomass burning inventories, the Global Fire Emissions Database (GFED4) and the Fire INventory from NCAR (FINNy 1), …
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Elemental and reactive gaseous mercury deposition and diurnal cycles over terrestrial environments
The atmospheric component of the global biogeochemical mercury cycle was studied to determine the mechanisms behind diurnal trends and amplitudes in elemental and reactive gaseous mercury concentrations over terrestrial environments. This analysis was done using the 3D GEOS-Chem chemical transport …
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Development and Acceleration of Parallel Chemical Transport Models
Improving chemical transport models for atmospheric simulations relies on future developments of mathematical methods and parallelization methods. Better mathematical methods allow simulations to more accurately model realistic processes and/or to run in a shorter amount of time. Parellization …
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Atmospheric implications of untested carbonyl photochemistry: an evaluation using chemically explicit and global 3D modelling
… radicals. Recent laboratory findings on the photochemistry of several aldehydes have yielded new photochemical and photophysical mechanisms that are of unknown importance in atmospheric chemistry, which paves the way for this thesis. Here, two atmospheric models, GEOS-Chem and AtChem2, were used …
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Quantifying Terrestrial and Aquatic Ecosystem Methane Emissions with Process-based Biogeochemistry and Atmospheric Transport and Chemistry Models
… a newly developed process-based lake biogeochemical model and a widely used 4-D VAR inversion algorithm implemented with the nested grid high-resolution GEOS-Chem Adjoint model.
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Plume to global-scale atmospheric impacts of aviation emissions
… 28]. These environmental impacts are driven by chemical, microphysical and transport processes that span different magnitudes of temporal and spatial scales, from near-field inplume chemistry that evolve over minutes and distances of ~100 m to global-scale phenomena taking place at the …
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Applications of Adjoint Modelling in Chemical Composition: Studies of Tropospheric Ozone at Middle and High Northern Latitudes
Ozone is integral to tropospheric chemistry, and understanding the processes controlling its distribution is important in climate and air pollution contexts. The GEOS-Chem global chemical transport model and its adjoint are used to interpret the impacts of midlatitude precursor emissions and …
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Efficient Computational Tools for Variational Data Assimilation and Information Content Estimation
… of this dissertation are to advance the field of chemical data assimilation, and to develop efficient computational tools that allow the atmospheric science community benefit from state of the art assimilation methodologies. Data assimilation is the procedure to combine data from observations with …
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Quantifying mercury surface fluxes by combining atmospheric observations and models
… Although an important component of its biogeochemical cycle, large uncertainties still exist in the estimates of surface fluxes of mercury. Three projects presented in this thesis improve our understanding of mercury surface fluxes at different spatial scales by combining atmospheric …
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Human health impacts of high altitude emissions
… and damages or benefits to human health via photochemical effects. Changes in population exposure to fine particulate matter, ozone and UV-B radiation resulting from current and future high altitude emissions are calculated, applying epidemiologically-derived impact functions to estimate resultant …
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Tropospheric Ozone over the Middle East and Its Interannual Variability: An Integrated Analysis with Satellite Observations and a Global Chemical Transport Model
… ozone measurements are scant. In this study, the GEOS-Chem chemical transport model is used to interpret newly available tropospheric ozone data from the Tropospheric Emission Spectrometer (TES) satellite instrument. TES reveals elevated ozone in the mid-troposphere (500-300 hPa) over the Middle …
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Impacts of emission policies in China on air pollution and human health
… strategies requires understanding policy costs, chemical non-linearities in pollution formation, and the value of health benefits. China suffers from severe air pollution, and is implementing both policies, but relevant studies are limited. This thesis incorporates three studies that examine the …
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Comparisons of an aerosol transport model with a 4-year analysis of summer aerosol optical depth retrievals over the Canadian Arctic
… et d’autre part du modèle de transport chimique (GEOS-Chem : Goddard Earth Observing Système Chemistry). Les produits d’AOD associés à l’algorithme d’inversion sont divisés en composantes totales, fines et grossières. Pour chacune des 5 stations (Barrow, Alaska, Resolute Bay, au Nunavut, 0PAL et …
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Investigating Variation in Launch Vehicle Atmospheric Impact by Launch Latitude and Season
… and launch season. I perform five two-year GEOS-Chem High Performance simulations, modeling the impact of 3000 Falcon-Heavy launches respectively across the months of January and July from Cape Canaveral in Florida and Rocket Lab Launch Complex in New Zealand. By examining zonal mean ozone …
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Air quality impacts of crop residue burning in India and mitigation alternatives
… viable. This thesis applies adjoint of the GEOS-Chem regional chemistry-transport model in combination with epidemiological and economic models to inform rational decision-making. First, this thesis estimates the premature deaths as 43,000-73,000 valued at 10-23 billion USD in India …
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Satellite constraints on surface concentrations of particulate matter
… observations can be used in conjunction with a chemical transport model (GEOS-Chem) to better understand this relationship. First, we investigate the seasonality in aerosols over the Southeastern United States using observations from several satellite instruments (MODIS, MISR, CALIOP) and …
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Sensitivities of Atmospheric Composition to High-Altitude Vehicles Emissions
… matter (PM₂.₅) concentrations. We used the GEOS-Chem chemistry-transport model to quantify the atmospheric sensitivities linked to civil supersonic transport, specifically evaluating the consequences of four distinct supersonic emission inventories on surface ozone, global column ozone, and …
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Application of the complex step method to chemistry-transport modeling
Sensitivity analysis in atmospheric chemistry-transport modeling is used to develop understanding of the mechanisms by which emissions affect atmospheric chemistry and composition, to quantify the marginal impact of emissions on air quality, and for other applications including improving estimates …
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An uncertainty-focused approach to modeling the atmospheric chemistry of persistent organic pollutants
… of uncertainty in emissions and physicochemical properties (including reaction rate constants) to Northern Hemisphere (NH) and Arctic PAH concentrations. NH average concentrations are more sensitive to uncertainty in the atmospheric lifetime than to emissions rate. The largest …
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Atmospheric Impacts of Hydrogen as an Aviation Fuel
… the non-CO₂ effects of these fleets. We use the GEOS-Chem High Performance (GCHP) global chemistry-transport model to conduct a spatially discretized, multi-year impact assessment of the atmospheric impacts of hydrogen-fueled aviation. We implement a flux surface boundary condition for hydrogen …
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