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 30 for “"atmosphere model"”.
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Methods for Rigorous Uncertainty Quantification with Application to a Mars Atmosphere Model
… practical example is uncertainty in a Mars atmosphere model due to the incompletely characterized presence of dust. The contributions made in this dissertation, though primarily mathematical and philosophical, are driven by the immediate needs of engineers applying uncertainty quantification …
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Simulating South African Climate with a Super parameterized Community Atmosphere Model (SP-CAM)
… Parameterised induced General Circulation Model (GCMs) are unable to represent clouds and aerosol particles explicitly and their influence on the climate and are thought to be responsible for most of the uncertainty in climate predictions. Therefore, the aim of the study is to investigate …
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Improving parameterization of scalar transport through vegetation in a coupled ecosystem-atmosphere model
Several regional-scale ecosystem models currently parameterize subcanopy scalar transport using a rough-wall boundary eddy diffusivity formulation. This formulation predicts unreasonably high soil evaporation beneath tall, dense forests and low soil evaporation beneath short, sparse grass. This …
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Sensitivity study and stability analysis of the Marotzke and Stone ocean-atmosphere model under buoyancy and energy constraints
… using the Marotzke and Stone four box ocean-atmosphere model under both the buoyancy constraint proposed by Stommel and the energy constraint proposed by Huang. Both a sensitivity study and stability analysis is performed. In the sensitivity study it is evident that the model under the …
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Spectral behavior of the coupled land-atmosphere system
… of the energy coupling between the land and the atmosphere in response to a forcing of incoming radiation at their common boundary, the land surface. This is of fundamental importance as that the initial/ boundary conditions of the land-surface state variables (e.g. soil moisture, soil …
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Representation of Mean Precipitation and Decadal Variability in Atmosphere Models
… over Europe and the Sahel using the atmosphere model OpenIFS. I found that European extreme precipitation is better represented at higher horizontal resolution, while the model time step has a limited effect on total precipitation extremes. For European winter precipitation, internal …
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Observations and Modelling of Thermospheric Dynamics at High Latitudes
… is available about this region of the atmosphere, model simulations by the WACCM-X model are employed. Model simulations, along with WINDII observations, allowed describing in a great detail most of the wind wall features, as well as its impact on other altitudes and regions. One of the …
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A time-varying subsidence parameterization for the atmospheric boundary layer
… layer (ABL) on a one-dimensional coupled land-atmosphere model. Measurements of large-scale divergence in the ABL are scarce and often marred by error, providing the motivation to model this important physical process and estimate its values from indirect but related observations. Constant …
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Differential polarization of Hβ in γ CAS
… the underlying star by fitting the Hubeny (1988) atmosphere model. The Be star model developed by Poeckert and Marlborough (1978a) for γ Cas is used as a basis to explain our polarization observations. We have made two types of modifications to the model: the first being to revise the intrinsic …
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The Effect of Orbital Forcing on the MJO’s Amplitude and Phase Speed
… cycle in the Superparameterized Community Atmosphere Model, which reasonably represents the MJO, by changing Earth's orbital parameters. In response to the orbital forcing, boreal winter mean precipitation increases, consistent with a stronger Hadley circulation, and the mean …
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Atmospheric signal delay affecting GPS measurements made by space vehicles during launch, orbit and reentry
In this thesis, I present neutral atmosphere, ionosphere and total delays experienced by GPS signals traveling to space vehicles during launch, orbit and reentry. I calculate these delays for receivers at 0 km to 1700 km altitude by ray-tracing through the Global Reference Atmosphere Model (1999) …
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Convective Transport of Tropical Marine Boundary Layer Species into the Upper Troposphere and Relation to Species Lifetime: In Situ Measurements and Global Model Simulation
… data, we also examine simulations from the Whole Atmosphere Community Climate Model (WACCM) with artificial tracers with lifetimes similar to our observed trace gasses. The Community Atmosphere Model with chemistry (CAMchem) is also used. Modeled results fit well with results from measured trace …
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Constraining a historical black carbon emission inventory of the United States from 1960-2000
… ambient air concentrations using the Community Atmosphere Model. I formulated the relationship between emissions and concentrations into matrices that allow reconstruction of emission for a time-varying ambient air concentration. When calculating the transport matrices from the model simulation …
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Ozone chemistry during global glaciations : a possible climate feedback
… ozone processes is discussed. An elementary box model is developed by the author to make first order judgments regarding the significance of chemistry changes on ozone concentrations and its climactic effect. A one dimensional photochemical-transport model (Kasting, 1995) was used to more …
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Modeling the Martian Atmosphere at Potential Landing Sites and Regions of Notable Topography
… of this mission, an understanding of the Martian atmosphere is necessary. This is the first mission that may determine the landing site based on weather conditions. As such, potential landing sites at Terby Crater, Melas Chasma, Gale Crater, and Nili Fossae Trough were studied. Due to limited …
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In Space Reverse Logistics
… servicing (OOS). A modular probabilistic Failure Model is proposed, designed, and implemented to collaborate with a custom-made orbital propagator to work as a space logistics simulator. The ISRL Failure Model is a modular and resilient binary random stochastic process with time-varying …
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Characterization of the impacts of the physiological response of vegetation to increasing levels of atmospheric carbon dioxide
… affects plant physiology. Using a coupled land-atmosphere model, multiple simulations have been conducted to examine the impact of the physiological response of vegetation to varying levels of CO2 near the leaf surface. Results showed that the impact of increased CO2 on stomatal conductance …
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High-latitude coupling processes between thermospheric circulation and solar wind driven magnetospheric currents and plasma convection
… time-dependent and self-consistent Upper Atmosphere Model (UAM). This model describes the thermosphere, ionosphere, plasmasphere and inner magnetosphere as well as the electrodynamics of the coupled MIT system for the altitudinal range from 80 (60) km up to the 15 Earth radii. In the …
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The role of biosphere-atmosphere-ocean interactions in the climate of West Africa during the Middle Holocene
… symmetric, synchronously coupled biosphere-atmosphere model (ZonaIBAM), which includes explicit representation of ecosystem dynamics, has been developed and validated based on current forcings over the region of West Africa. Here, we use ZonalBAM to study the response of the coupled …
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The management of aircraft passenger survival in fire.
… characteristics of such combustion atmospheres and related effects on animals and humans. Using this data, the approach used to develop a set of acceptance criteria for aircraft passenger smoke hood designs is described. In addition, the way in which a challenge combustion atmosphere …
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