Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Maryland, College Park, 1997. / Thesis research directed by Dept. of Meteorology. Includes bibliographical references (leaves 122-134).

No description available.

In April and May of 1976 an anomalous situation occurred in that no tornadoes were reported for Indiana. This study attempts to determine possible relationships that may have caused the anomalous situation. To better understand the factors surrounding this situation, this study deals with a physical survey of Indiana and a review of literature involving conditions for tornado development. The study tests for relationships between tornadoes, storm tracks, and storm track location relevant to Indiana for the months of March, April, and May, 1955 to 1976, that might suggest reasons for the anomalous situation occurring. Statistical analyses involving correlation tests and analysis of variance, are used to test for possible relationships.

Survey responses from 76 public school districts in Mississippi and Alabama, tornado warning data, tornado path data, and county demographic data were used to investigate early dismissals in public schools. There was little agreement among survey responses and this inconsistency supports the idea that each situation is unique and one plan may not be successful for all districts. The highest number of reported dismissals would have resulted in a loss of less than 2% of the total annual class time. A higher number of recent killer tornadoes, a lower level of poverty, and a team rather than individual decision were the three most important variables in determining which districts would dismiss more often. The seven districts that reported not dismissing were all well below the national poverty average. Other important factors included smaller county area, higher number of killer tornadoes since 1950, and serving a county rather than city population.

Thesis (M.S.)--Mississippi State University. Department of Geosciences. / Title from title screen. Includes bibliographical references.

Two numerical models, described in detail herein, have been constructed and used to investigate the formation of secondary vortices in axisymmetrically-forced rotating flows. The particular type of vortex flow examined is that developed in a laboratory vortex simulator where secondary vortices have been produced and extensively studied. The first numerical model generated a collection of steady state, axisymmetric vortex flows based on a range of swirl ratios. The second model tested those flows for instability by simulating the behavior of small amplitude, axially asymmetric, linear perturbations superimposed on the flows: amplification of the perturbations indicated instability whereas damping indicated stability. For those flows found to be unstable, the linear perturbations of various azimuthal wavenumbers were analyzed in detail, and from the perturbation growth rates, structures, phase speeds, and energetics, the nature of the instability could be studied. The results of the instability study show that the vortex is stable for the lowest swirl ratios but that above a certain value, instability persists indefinitely. The most rapidly growing wavenumber shifts steadily with increasing swirl from 1 to around 5 in the swirl range investigated. Growth rates were found to be high enough for secondary vortices to form in the laboratory simulator in just a few seconds. Structurally, the perturbation fields were found to have a helical tilt and to be centered near the radius of maximum vertical vorticity in the axisymmetric vortex. They propagated in the same azimuthal direction as the rotation of the axisymmetric flow, but at a somewhat lower angular velocity at the surface. These linear results are all consistent with observed laboratory behavior. From this, it was concluded that linear theory is capable of explaining many important aspects of secondary vortices. An analysis of the perturbation energy equation revealed that at the higher swirl ratios, the perturbation received most of its energy from the deformation of the axisymmetric flow due to the radial distribution of azimuthal velocity, while for low swirl the primary source was from the radial distribution of the vertical velocity. No other component of the axisymmetric vortex ever contributed more than about 25% of these terms.

Thesis (Ph. D.)--University of Oklahoma, 1993. / Includes bibliographical references (leaves 296-305).

Thesis (Ph. D.)--University of Oklahoma, 2000. / Includes bibliographical references (leaves 105-115).