Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. T.N. Krishnamurti, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed Aug. 26, 2004). Includes bibliographical references.

Thesis (M.S.)--Ohio University, June, 2005. / Includes bibliographical references (p. 129-135)

Thesis (M.S.)--Ohio University, June, 2005. / Title from PDF t.p. Includes bibliographical references (p. 129-135)

Atmosphere-biosphere exchange plays a key role in the global cycles of water and carbon. Air pollution can alter these processes and induce climate perturbations and feedbacks. Surface ozone (O3) is an air pollutant and greenhouse gas that is toxic to plants, reducing their growth and ability to regulate water loss. Past controlled experiments have shown that O3 degrades a plant's water-use efficiency (WUE), which is the ratio of carbon uptake in photosynthesis to water loss in transpiration. This has potentially significant implications for terrestrial water cycle and precipitation, but no studies have evaluated the O3 effect on WUE in complete ecosystems. We aim to quantify the impact of O3 on WUE across a wide array of ecosystems. Meteorological and biological data was obtained from 23 FLUXNET flux tower sites, which use the eddy covariance method to derive hourly fluxes of carbon dioxide (CO2), water vapor (H2O), and O3 between the atmosphere and ecosystem. Across a broad range of sites, we find a significant negative relationship between daily anomalies of stomatal O3 flux (FS, O3) and WUE that explains 1-3% of WUE variability. The largest impacts occur in locations and species with high stomatal conductance, such as broadleaf forests, humid climates, or irrigated crops, rather than where surface O3 concentrations are highest. Past long-term studies have also found similar O3 impacts (1-3%) on WUE, indicating a consistent response across a pool species and ecosystems. / A Thesis submitted to the Department of Earth, Ocean, & Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2016. / March 23, 2016. / Ecosystems, FLUXNET, Natural environments, Stomatal ozone flux, Water-use efficiency / Includes bibliographical references. / Christopher D. Holmes, Professor Directing Thesis; Stephanie Pau, Committee Member; Vasu Misra, Committee Member; Jon Ahlquist, Committee Member.

Atmospheric water vapor is a potent greenhouse gas, and its variations in the upper troposphere and lower stratosphere (UTLS) have important climate impacts. The water vapor budget of tropical cyclones (TCs) and their impact on the UTLS remain understudied. This paper describes high-resolution simulations of TC Ingrid during September 2013 using the Weather Research and Forecasting (WRF) model to calculate the water vapor budget. Using Ingrid as an example provides a better understanding of water vapor transport into the UTLS by TCs, helping to answer a question posed during NASA’s Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling through Regional Surveys (SEAC4RS), specifically whether water vapor transport in TCs hydrates or dehydrates the UTLS. Our WRF simulations of TC Ingrid closely correspond to the National Hurricane Center’s Best Track data. We also evaluate model results of the water vapor budget with in situ airborne data of Ingrid collected during the SEAC4RS mission. Satellite imagery also is used to validate the simulated structure of Ingrid. We show spatial and temporal changes of UTLS water vapor throughout Ingrid's lifecycle to determine whether and how TCs hydrate or dehydrate the UTLS. Results show that TCs do transport large quantities of water vapor into the UTLS, and overshooting deep convection is an especially potent transport method. The paper sheds light on mechanisms that inject water vapor into the UTLS and on the widespread horizontal and vertical transports of water vapor within TCs. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the Master of Science. / Fall Semester 2016. / November 22, 2016. / flux, lower stratosphere, transport, tropical cyclone, upper troposphere, water vapor / Includes bibliographical references. / Henry Fuelberg, Professor Directing Thesis; Robert Hart, Committee Member; Vasu Misra, Committee Member; Christopher Holmes, Committee Member.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). "November 24, 2009." Includes bibliographical references (p. 325-330). Also available via the World Wide Web.

Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007. / Robert Dickinson, Committee Member ; Athanasios Nenes, Committee Member ; David Tan, Committee Member ; Armistead Russell, Committee Member ; Yuhang Wang, Committee Chair.

Experiments have been conducted with a two-dimensional timedependent, numerical model of the general circulation of the atmosphere up to the mesopause. A scheme for the calculation of cooling rates due to the 15(mu)m band of carbon dioxide is developed. It uses the Curtis matrix approach which incorporates cooling-to-space, transfer of radiation between atmospheric layers and non-equilibrium effects in the upper mesosphere. The sensitivity of the cooling rate calculations to the choice of collisional relaxation time is investigated. An 'almost exact' scheme to calculate heating rates due to the absorption of solar radiation by ozone and molecular oxygen is presented. Use of both new radiation schemes enables the diabatic heating rate to be calculated to the upper boundary of the model. Other heat sources in the region of the mesopause are discussed. Incorporation of the new schemes considerably improves the modelled temperature structure of:the stratosphere and lower mesosphere. The upper mesosphere is not well reproduced with no indication of the observed cold summer mesopause. The heat and momentum budgets of the mesosphere are studied. Eddy momentum fluxes derived from satellite observations of planetary waves are found to be significant for the circulation and transport properties of the stratosphere but incapable of producing the required distribution of angular momentum in the mesosphere. A Rayleigh friction parameterisation is included in the mesosphere to reproduce the observed zonal wind and temperature structure. Momentum deposition by tides and gravity waves is discussed. Curtis matrices are calculated with higher mixing ratios of carbon dioxide and the effects of increased atmospheric CO2 on stratospheric temperatures and ozone is investigated. Temperature decreases of up to about 10K are predicted with increases in ozone concentration in the upper stratosphere. In the lower stratosphere the ozone increases are restricted to high latitudes and a decrease shown in equatorial regions. The latitudinal variations are reflected in the ozone column density. An experiment is conducted in which chlorofluorocarbons are released into the model atmosphere and the effects on stratospheric ozone are in exactly the opposite sense to those predicted for the CO2 case. A run in which CO2 and CFCs are introduced simultaneously shows that the two effects are not linearly additive. A simple photochemical theory is used to investigate the temperature dependence of ozone and to explain the non-linearity of the coupled experiment.

We have conducted an extensive experimental study on the subject of near ground atmospheric electricity. The main objective was to gain more understanding of this particular aspect of atmospheric phenomena, while testing the possible application to cosmic ray research. The results in atmospheric electricity show that there are certain patterns in ion grouping such as the size and lifetime. The average lifetime of ion group is 0.7 seconds and the average size is about 10 meters at our experimental site. Ultrahigh energy cosmic ray air showers should create sizable slow atmospheric electric pulses according to our theoretical calculations. Preliminary studies on air showers with total particle number N equal or greater than 10⁵ (10¹⁵ eV) have yielded strong evidence that slow atmospheric current pulses are associated with air showers. The theory and the experiment agree with each other fairly well when we average over large numbers of events. With our current experimental arrangement, when the air shower exceeds a certain size, the system response saturates. Therefore it is extremely desirable in future research that the counter array be designed for a much higher threshold level, since this prototype experiment indicates that interesting data would be obtained. Another reason for further experimental research being directed toward ultrahigh energy, e.g., N ≥ 10⁷ (10¹⁷ eV) and higher, is to establish a calibration of the slow atmospheric electric signals generated by cosmic rays as a function of primary cosmic ray energy and core location. This type of slow atmospheric electric signal, if fully understood and calibrated, offers a new and potentially less expensive technique to observe ultrahigh energy cosmic ray events, which hold some fundamental keys to the knowledge of the universe on a large scale.