Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 68-69).

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 39-42).

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University. / Bibliography: p. 21-23. Also available online.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 97-103).

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 140-152).

Supervisor: Professor Robert W. Stewart The process by which the wind makes sea waves grow is not well-understood, partly because of the lack of adequate observational information on the normal pressures which transfer energy to the waves. The principal object of this experiment has been to provide some of the missing data. A system for making simultaneous measurements of normal pressure and wave height was developed and tested in the laboratory and in the field. The system consisted of a disc-shaped buoy 23 cm in diameter (in which was embedded the pressure sensor) which rode up and down on a vertical rod, which was the wave sensor. Careful attention was paid to rejecting so-called "dynamic" pressures associated with the distortion of the air flow by the buoy. The results from the experiment are presented as power and cross-spectra of the pressure and wave signals. Spectra of Energy (E) and Momentum (τω) fluxes to the waves, and of ζ, the fractional energy increase of the waves per radian, are also presented. Wave power spectra are found to be normal for the site; the pressure power spectra consist of a "basic" spectrum similar to that observed over land, on which is superimposed a wave-induced "hump". The phase angle between the waves and the pressure at the frequency of the peak of the wave spectrum is found to be shifted from -180° (pressures high over wave troughs) by amounts which exceed the theoretical predictions of Miles (1957) by an average of 20 ± 5° over a wide range of conditions. The Ė and τω spectra are found to be sharply peaked at or above the frequency of the peak of the wave spectrum. The integrated energy fluxes Ē show large scatter, indicating that the wave generation process varies considerably in time (and space). The integrated momentum fluxes τω to the waves show no significant difference from total fluxes from air to water computed assuming a constant drag coefficient of 1.2 x 10⁻³; it appears that about 80% of the total drag of the water on the wind is caused by the wave generation process. The ζ spectra exceed the predictions of Miles' (1957) theory by factors of 5 to 8, indicating that his "inviscid laminar" model is not adequate to explain observed rates of wave growth. The present results fall close to an empirical curve suggested by Snyder and Cox (1966) except at high frequencies, where they are considerably lower. A dimensionless plot of ζ versus the ratio of wind speed to wave speed is presented; the observed data is fitted by the simple relation [formula omitted], where [formula omitted]is the ratio of the densities of air and water, U₂ is the mean wind speed at a height of two meters, and c is the phase velocity of the waves. This formula is only considered applicable for U₅/c < 6, where U₅ is the mean wind speed at 5 meters height. Also presented are the results of a dry-land comparison of the buoy pressure sensor with two other pressure sensors; besides indicating that the buoy sensor was adequate, this comparison produced some interesting preliminary information on the vertical and horizontal structure of the turbulent pressure field in the atmospheric boundary layer. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Bibliography: pages 143-154. / The relationships between interannual sea surface temperature variability (SST) of the oceans surrounding southern Africa and summer rainfall variations over South Africa are investigated using statistical, observational and mechanistic approaches. Positive correlations are identified between summer rainfall and SSTs of the Mozambique/ Agulhas Current region, the Agulhas Retroflection region and the northern Benguela Current system. These relationships are stronger when rainfall anomalies associated with the Southern Oscillation are not considered. The observation of significant lag relationships involving temperatures of the Agulhas Current system suggests that future prediction efforts for summer rainfall will benefit from a consideration of SST anomaly patterns east and south of Africa, in combination with other atmospheric indices. Surface winds, heat fluxes and atmospheric boundary layer characteristics are investigated using compositing analyses to assess pertinent ocean-atmosphere coupling mechanisms. Easterly wind anomalies across the southwest Indian Ocean and over source regions of the Agulhas Current accompany and precede the local oceanic "warm events" which correspond with higher rainfall. Thus a class of event is identified in which warmer waters along the east coast and stronger easterly wind forcing accompany wetter seasons over South Africa. The atmospheric boundary layer is considerably warmer and moister in association with positive SST anomalies along the east coast and increased tropical airflow. Consequently, moisture convergence and tropical convection are increased over the eastern interior near 20° to 25°S. South of Africa, positive SST anomalies generate surface heat flux anomalies, increasing instability and moisture levels within the boundary layer. Horizontal heat flux gradients are strengthened across the Agulhas/Subtropical Convergence SST front and the conditions necessary for cyclogenesis and westerly wave amplification are optimized. Tropical-temperate troughs account for most of the abnormal rainfall during local Agulhas "warm events". The presence of positive SST anomalies east and south of southern Africa increases the likelihood of their formation by intensifying tropical and temperate components. The contribution provided by each component is influenced by the position and magnitude of the SST anomaly as well as the season of occurrence. Conceptual models are presented which summarize the most important ocean-atmosphere coupling mechanisms associated with rainfall variations of southern Africa.

Observations of wind speed and direction, air and sea temperature, and solar radiation were obtained from an array of buoys in JASIN. The observations were analyzed to show spatial and temporal variability. Spectra of wind speed and air and sea temperature were computed to illustrate the distribution of variance over periods ranging from 3.5 minutes to 40 days. When plotted on log-log graphs the spectral estimates generally decrease with increasing frequency with slopes between -3/2 and -2. Spectra of air and sea temperature have a peak at the diurnal frequency. When plotted in variance-preserving form, the spectrum of wind speed is consistent with a spectral gap and is qualitatively similar to other observations of low frequency spectra. On the basis of a cross-correlation analysis, it appears that mesoscale eddies propagated with the mean wind speed except during frontal passages. Based on the cross-correlation between wind speed and air temperature, there is evidence of horizontal roll vortices or organized convection. / Graduation date: 1980

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