Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 87-91).

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This study addressed the problem of water vapor production and distribution in comet P/Halley, based upon interpretation of observational data obtained during the recent 1985-86 apparition. The data was acquired using the Lunar and Planetary Laboratory charge-coupled device (CCD) on the 154-cm Catalina telescope of the University of Arizona Observatories. Our data acquisition system was employed in two modes. The long-slit (∼200") spectroscopy mode covered the wavelength range 5200-10400 Å at a spectral resolution ∼14 Å. The narrow band filter imaging mode allowed two-dimensional mapping of selected cometary emission features, as well as the continuum, with a field of view of roughly 10 arc-min. Both neutral and ionized (H₂O⁺) water species were studied, with emphasis on the ion distribution. This involved comparing long-slit spatial profiles obtained ∼UT 1986 March 05.5, as well as cuts across filter images (∼ March 06.5) centered on the H₂O⁺ 0,8,0-band emission, with the Vega-1 spacecraft in situ ion density measurements (∼ March 06.3). Our March 05 spectroscopic data revealed a central dip, of order 30% relative to the profile peak, in H₂O⁺ column density in the inner coma (inside ∼ 2 x 10⁴ km from the nucleus), which filled in farther tailward. Similarly the BD - 3 plasma detector aboard Vega-1 measured a decrease in local ion density, of roughly 60% at the closest approach distance (∼ 9000 km sunward of the nucleus), relative to the inbound maximum density at R ≃ 12000 km from the nucleus. These results suggest a bimodal flow of ions out of the coma and/or an extended region over which the H₂0 molecules were being ionized. Our imaging data showed that, while the falloff in ion density was relatively rapid sunward of the nucleus, it was much more gradual in the anti-solar direction. This is due to the solar wind sweeping ions from the head of the comet into the plasma tail, whose width was of order 10⁵ km in the inner coma, diverging slowly and breaking up into a ray pattern farther tailward. The distribution of neutral water was mapped out using the [O I] λ6300 emission as diagnostic probe. In contrast to the ions, the H₂0 molecules were mainly confined to the inner few x 10⁴ km of the coma, and exhibited a much more symmetrical distribution. Integration of the [O I] slit profiles, assuming azimuthal symmetry, allowed calculation of the H₂0 production rate, which ranged from ∼ 10²⁸ molecules s⁻¹, when Halley was at a distance r≳ 2 AU from the sun, to a value of ∼ 1.5 x 10³⁰ molecules s⁻¹ for 1986 March 05 (r ≃ 0.78 AU). Using the latter production rate, and assuming a 100/1 production ratio of H₂0/ H₂O⁺, a spatially-averaged, tailward flow speed of ions out of the inner coma, < v⁺ > ≃ 16 km s⁻¹, was derived by integrating our March 05 H₂O⁺ profile, for which the slit was oriented across the coma, just tailward of the nucleus.

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Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 122-130). Also available via the Internet.

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The investigators do not preclude the possibility that there could be designed and built a water injection device that would operate under the conditions which were imposed on the Briggs' Vapor Jet for the purpose of this investigation. If, however, such a device be built, it is felt that it must be subject to controls of many kinds based on all the variables that affect the highly critical vapor injection problem. The complex nature of such a device makes it highly unlikely that it could find commercial use in the private automobile field. Water injection itself is apparently not more than just barely effective at the compression ratios now being used in passenger car engines. That, considered from both the viewpoint of increasing; the engine's power and performance and from the standpoint of economy, is largely responsible for the ineffectiveness of this Jet. The fact that this device can be mounted on any stock model car with a minimum of work, and that it will produce some results from an economic standpoint may justify its installation in cases where its effect on over-all engine operation and power are not too important. / M.S.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 270-273).

The present work focuses on the sources and transport of water vapor to the La Plata Basin (LPB), and the role of groundwater dynamics on the simulation of hydrometeorological conditions over the basin. In the first part of the study an extension to the Dynamic Recycling Model (DRM) is developed to estimate the water vapor transported to the LPB from different regions in South America and the nearby oceans, and the corresponding contribution to precipitation over the LPB. It is found that more than 23% of the precipitation over the LPB is from local origin, while nearly 20% originates from evapotranspiration from the southern Amazon. Most of the moisture comes from terrestrial sources, with the South American continent contributing more than 62% of the moisture for precipitation over the LPB. The Amazonian contribution increases during the positive phase of El Niño and the negative phase of the Antarctic Oscillation. In the second part of the study the effect of a groundwater scheme on the simulation of terrestrial water storage, soil moisture and evapotranspiration (ET) over the LPB is investigated. It is found that the groundwater scheme improves the simulation of fluctuations in the terrestrial water storage over parts of the southern Amazon. There is also an increase in the soil moisture in the root zone over those regions where the water table is closer to the surface, including parts of the western and southern Amazon, and of the central and southern LPB. ET increases in the central and southern LPB, where it is water limited. Over parts of the southeastern Amazon the effects of the groundwater scheme are only observed at higher resolution, when the convergence of lateral groundwater flow in local topographical depressions is resolved by the model. Finally, the effects of the groundwater scheme on near surface conditions and precipitation are explored. It is found that the increase in ET induced by the groundwater scheme over parts of the LPB induces an increase in near surface specific humidity, accompanied by a decrease in near surface temperature. During the dry season, downstream of the regions where ET increases, there is also a slight increase in precipitation, over a region where the model has a dry bias compared with observations. During the early rainy season, there is also an increase in the local convective available potential energy. Over the southern LPB, groundwater induces an increase in ET and precipitation of 13 and 10%, respectively. Over the LPB, the groundwater scheme tends to improve the warm and dry biases of the model. It is suggested that a more realistic simulation of the water table depth could further increase the simulated precipitation during the early rainy season.

The present study contains a calculation and discussion of meridional advection of water vapour on a daily basis across three latitude circles (65°N., 70°N., 80°N.) for the months of January and July, 1958. [...]