Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 116-118).

Thesis (M.S.)--Ohio University, November, 2000. / Title from PDF t.p.

Thesis (M.Sc.) -- University of Adelaide, School of Chemistry and Physics, Discipline of Physics, 2007. / "February 19, 2007" Bibliography: pages 147-154. Also available in print form.

Thesis (Ph. D.)--Indiana University, School of Public and Environmental Affairs, 2007. / Title from dissertation home page (viewed May 28, 2008). Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7189. Adviser: Ronald A. Hites.

Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Kevin S. Repasky. Includes bibliographical references (leaves 49-51).

Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 108-111).

Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract. Includes bibliographical references (leaf 80).

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Utilizing analyses of observational data, we performed a detailed study to investigate short-period atmospheric gravity waves and ripples, and instabilities in the mesopause region. Recent coordinated measurements from Haleakala Observatory, Maui, HI via airglow wave imaging, meteor wind radar, and Na wind temperature lidar have provided a unique dataset for this study. Gravity waves generated in the lower atmosphere propagate energy upwards into the mesosphere and lower thermosphere region where they modulate the airglow emissions, and later break and deposit their momentum, causing significant perturbations in winds and temperatures. Ripples, on the other hand, are likely generated by localized shear instabilities in the background wind eld, and are also observed frequently in airglow images. First, we investigated the frequency of occurrence and climatology of ripples and their seasonal variation in propagation directions of motion. These novel results were then used to characterize the nature of the observed ripples and to identify individual Kelvin Helmholtz instability events as their sources, which were consistent with theoretical computations. The results provided insight to better quantify seasonal wave anisotropy and instability dynamics in the mesopause. Second, we investigated ground-relative and intrinsic properties of gravity waves that were Doppler-ducted or evanescent. The results were then compared with an analytical model and numerical model simulations for the Doppler-ducted and evanescent waves, demonstrating signicant dierences in wave structures for apparently similar wave events. Results reinforced the need to better understand the dynamics of wave ducting and their importance for momentum and energy transports at upper mesosphere and lower thermosphere heights. Third, we investigated the frequency of occurrence of frontal disturbances and the appearance of complementary intensities in OH and O2 airglow emissions. We have analyzed ducting conditions of mesospheric bores. One bore event was trapped in a stable Doppler duct arising from wind structure, and other bore events were trapped within thermal inversion layers. Analysis confirmed that the measured ducted bore events were separately consistent with theoretical Doppler-ducted and thermal-ducted wave characteristics. These studies provide an extensive dataset for detailing the morphology and dynamics of mesospheric frontal events.

The dust lifting capacity of the UK Mars General Circulation Model has been extended through the development of a new wind stress lifting parameterisation, and the simulation of a finite, variable surface dust layer. This second addition, which was represented by the use of lifting thresholds that were adjusted at each surface gridpoint in response to the removal or deposition of dust, led to enhanced variability in the timing and peak magnitude of major dust storms produced in the model. These dust storms were realistic in many respects, and the observed global dust storm frequency of occurrence of roughly one in every three years was approximately reproduced by the model, but an artificial threshold decrease rate was required to maintain dust lifting on a multiannual timescale - this was believed to be due to inaccuracies in the net cross-equatorial dust flux, which showed a strong bias towards the northern hemisphere. Significant changes were seen in model dust lifting rates when the influence of a heterogeneous surface roughness length was included in the wind stress scheme, and the need for more sophisticated sub-gridscale methods in future dust lifting schemes, to cope with this and other effects, was noted. The inclusion of radiatively active water clouds in model runs also affected dust lifting rates, particularly in the vicinity of the polar caps in autumn, winter and spring. The dynamics behind the formation of small, cap-edge dust storms during these periods were examined in detail, and it was found that a cessation in dust lifting activity that occurs around winter solstice does so due to a combination of the radiative effects of global dust loading and polar hood ice clouds, and zonal variations in midlatitude topography. The direct interaction between dust and ice, in the form of nucleation and scavenging, was investigated. It was found that scavenging by water ice, if it is suitably efficient, could significantly reduce the dust content of the winter polar regions. However, the dust and ice vertical profiles measured in the aphelion cloud belt by Mars Climate Sounder were not reproduced by the model with any of the possible scavenging efficiencies used. It appears that scavenging cannot provide an explanation for the existence of sharply defined, elevated dust layers at low latitudes.