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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Measuring transit timing variations of exoplanets using small telescopes

Morley, Caroline V January 2010 (has links)
Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 57-58). / Transits of exoplanets were observed from June 2009 through January 2010. Six transit light curves are presented in this paper for three planets: WASP-10b, WASP- 11/HAT-P-10b, and TrES-3. Measurements of the planetary radii, semi-major axis, transit duration, and period confirmed literature values to within two sigma. Transit timing variations were not observed in these systems, but calculations show that it would be possible to measure transit timing variations induced by large exomoons (greater than about 6 Earth masses) in the WASP-11/HAT-P-10b system. Challenges of exoplanet observation from small telescopes are discussed. It was determined that overall, transit measurements of many exoplanets using small telescopes can be successful and scientifically useful. / by Caroline V. Morley. / S.B.
102

Tidal dynamics and dispersion around coastal headlands

Signell, Richard P January 1989 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989. / Includes bibliographical references (leaves 160-162). / by Richard Peter Signell. / Ph.D.
103

Effects of stress, pore pressure, and pore fluids on bulk strain, velocity, and permeability in rocks

Coyner, Karl B January 1984 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Bibliography: leaves 317-322. / by Karl B. Coyner. / Ph.D.
104

The effect of compressibility, phase transformations, and assumed density structure on mantle viscosity inferred from earth's gravity field

Panasyuk, Svetlana, Valeryevna, 1965- January 1998 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998. / Includes bibliographical references (p. 147-148). / by Svetlana, Valeryevna Panasyuk. / Ph.D.
105

Linear and nonlinear elastic wave propagation in a fluid-filled borehole

Kostek, Sergio January 1993 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1993. / Includes bibliographical references (leaves 180-187). / by Sergio Kostek. / Ph.D.
106

Tropical cyclone intensification from finite amplitude disturbances, or, How hurricanes hardly happen.

Handel, Mark David January 1991 (has links)
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1991. / Includes bibliographical references (p. 241-261). / Sc.D.
107

Tropical cyclone size in observations and in radiative-convective equilibrium

Chavas, Daniel Robert January 2013 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 147-154). / Tropical cyclone size remains an unsolved problem in tropical meteorology, yet size plays a significant role in the damage caused by tropical cyclones due to wind, storm surge, and inland freshwater flooding. This work explores size, defined as the radius of vanishing wind, in observations and at equilibrium in an idealized numerical model. First, a climatology of size is created from the QuikSCAT database of near-surface wind vectors for the years 1999-2008. Globally, the distribution of the outer radius is found to be log-normal, with statistically significant variation across ocean basins, but with minimal correlation with various dynamic and thermodynamic parameters. Second, the sensitivity of the structure of a numerically-simulated axisymmetric tropical cyclone at statistical equilibrium to the set of relevant model, initial, and environmental external parameters is explored. The analysis is performed in a highly-idealized state of radiative-convective equilibrium (RCE). The non-dimensional equilibrium radial wind profile is found to be modulated primarily by a single nondimensional parameter given by the ratio of the storm radial length scale to the parameterized eddy radial length scale. The relevant storm length scale is shown to be the ratio of the potential intensity to the Coriolis parameter, matching the prediction for the "natural" storm length scale in prevailing axisymmetric tropical cyclone theory. The outer storm circulation is further modulated by a second non-dimensional parameter that represents the non-dimensional Ekman suction rate. Third, size is explored in three-dimensional "tropical cyclone world" simulations, with preliminary results confirming the relevant length scale obtained in axisymmetry. Ultimately, the results of the equilibrium storm analysis are insufficient to explain the observed distribution of tropical cyclone size, but they provide the first steps toward a more fundamental understanding of the dynamics of size. / by Daniel Robert Chavas. / Ph.D.
108

High-precision U/Pb geochronology of large igneous provinces and mass extinctions : testing coincidence and causation

Burgess, Seth Douglas January 2014 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references. / The history of life on Earth is punctuated by mass extinction, the cause of which has often been attributed to rapid changes in global climate and/or ocean chemistry that are inferred to accompany the eruption of large igneous provinces (LIPs). Implicating LIP eruptions as the trigger of the biologic crises has relied on the approximate coincidence in time between these two events. To test this causal link and to understand the mechanisms driving extinction requires a more accurate and precise temporal record of both events than currently exists. With higher precision, the ability to resolve the relative timing of mass extinction and magmatism outside the analytical uncertainty on dates populating age models is possible, allowing detailed investigation of a causal connection. The current work develops zircon and perovskite minerals as accurate, high-precision geochronometers on the mafic rocks that commonly characterize LIP magmas. These advances are coupled with the latest techniques in U/Pb geochronology to generate highprecision age models which are used to evaluate the relative timing of (1) the end- Permian mass extinction, which is the most severe in the Phanerozoic, and the Siberian Traps LIP, which is the largest continental magmatic event in the Phanerozoic, and (2) the Karoo-Ferrar LIP and the early-Jurassic biotic crisis and global ocean anoxia. With these datasets, age-models for both mass extinction and LIP magmatism precise to a maximum of ~0.02% are developed, enabling, for the first time, resolution of the relative timing of eruption and extinction outside of uncertainty. This work conclusively indicates that (1) Siberian Traps LIP magmatism precedes onset of the end-Permian mass extinction and continued through the mass extinction interval, into the early Triassic biotic recovery interval, and (2) Karoo-Ferrar LIP magmatism likely preceded the onset of early-Jurassic extinction and ocean anoxic event and continued through this interval, over ~ 1 Ma. / by Seth Douglas Burgess. / Ph. D.
109

An estimate of the upwelling rate in the tropical Pacific Ocean

Samuel, Sarah Louise, 1974- January 2000 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, February 2000. / Includes bibliographical references (p. 84-87). / An inverse box model of the tropical Pacific Ocean from 321S - 10N is constructed from two zonal and six meridional hydrographic sections. This data is supplemented with LADCP data close to the equator where geostrophy fails. A consistent solution is found despite the presence of a number of mid-ocean crossing points and the data being spread over many years and seasons. The total upwelling across the ... = 23.5 isopycnal surface in a 60 latitude band centered on the equator is estimated to be 55 ± 27Sv. The zonal mean cross-isopycnal velocity for the same surface in the same latitude band is estimated to be 6.88 t 3.23 x 10 4 cms- 1. The addition of radiocarbon data places a strong constraint on the vertical transfers in the model and significantly reduces the error on the estimated vertical transport and velocity. When radiocarbon constraints are included, the upwelling across the ... = 23.5 isopycnal surface in the equatorial zone is estimated to be 52 ± 16Sv and the zonal mean cross-isopycnal velocity across the same surface is estimated as 7.15 t 1.90 x 10- 4 cms-1 . That a consistent solution can be found is encouraging but it remains unclear whether one-time data is representative of mean conditions in a region which is known to be highly variable. / by Sarah Louise Samuel. / S.M.
110

Crustal structure from teleseismic bodywave data

Foley, John Edward January 1990 (has links)
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990. / Includes bibliographical references (leaves 245-255). / by John Edward Foley. / Sc.D.

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