Physics Commons^™

Gravity Wave Spectra Morphology In The Arctic And Non-Arctic Lower Atmosphere, Melanie C. Wright

Electronic Thesis and Dissertation Repository

The spectral analysis of data from three VHF radars (one high-Arctic and two mid-latitudes) show support for the universal spectrum theory for gravity waves in the lower atmosphere (altitudes of 2.0-11.0 km), provided that the impact of the off-vertical beam and noise are taken into consideration. This analysis also reveals that local gravity wave generation is of secondary importance, but still significant for determining the spectra.

A total of eight spectral methods were considered and scrutinized for the purposes of determining gravity wave spectra from VHF radar data. A definition for the “best” method was given and examined. The method …

Potential For Measurement Of Mesospheric Ozone Density From Overdense Meteor Trains With A Monostatic Meteor Radar, Reynold E. Sukara

Electronic Thesis and Dissertation Repository

Thermally ablating meteoroids, colliding with the Earth’s atmosphere, leave a high temperature trail containing extremely energetic metallic ions and electrons. A well recognized, but unresolved, anomaly associated with ambipolar diffusion of meteor trains, which is more dominant in overdense meteors, takes place in the initial post-adiabatic train expansion. In this work, a newly proposed mechanism explaining this anomaly involves hyperthermal chemical reactions is presented. Data from the SKiYMET meteor radar system, deployed at latitudinally dispersed locations, were used to determine ozone density in the upper atmosphere by analyzing diffusion of overdense meteor trains. The results obtained in this study are …

Simultaneous Radar And Video Meteors, Robert J. Weryk

Electronic Thesis and Dissertation Repository

The goal of this thesis is to better understand the physical and chemical properties of meteoroids by using simultaneous radar and video observations of meteors. The Canadian Meteor Orbit Radar (CMOR) and several Gen-III image-intensified CCD cameras were used to measure common meteors and validate metric errors determined through Monte Carlo modelling and to relate radar electron line density (q) to video photon radiant power (I). By adopting an ionisation coefficient from Jones (1997) and using recorded measurements of q/I, a corresponding estimate of the fraction of meteoroid kinetic energy loss converted into light (luminous efficiency) was found.

It was …

Validation And Application Of Wind Profiler Measurements Of Atmospheric Turbulence, Armin Dehghan

Electronic Thesis and Dissertation Repository

This thesis focuses on the investigation of the reliability of turbulence measurements by radars when the spectral-width method is used. This method employs the spectral widths observed by radar (experimental spectral width) to determine turbulence. However, the experimental width can be affected by non-turbulent effects, including radar geometry. Therefore, the spectral width due to non-turbulent effects (theoretical spectral width) must be removed from the experimental width. This can occasionally lead to negative values of turbulence.

It is our aim (1) to study the effects of both experimental and theoretical spectral widths on the accuracy of turbulence measurements, (2) to study …