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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.
191

The South Atlantic Ocean response to local and remote forcings /

Fetter Filho, Antonio F. H. January 1900 (has links)
Thesis (Ph. D)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 147-160). Also available on the World Wide Web.
192

Frictional convergence and the Madden-Julian oscillation /

Maloney, Eric Daniel. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 123-131).
193

Numerical and analytical modelling of oceanic/atmospheric processes

Weaver, Andrew John January 1987 (has links)
Two problems in oceanic/atmospheric modelling are examined in this thesis. In the first problem the release of fresh water from a midlatitude estuary to the continental shelf is modelled numerically as a Rossby adjustment problem using a primitive equation model. As the initial salinity front is relaxed, a first baroclinic mode Kelvin wave propagates into the estuary, while along the continental shelf, the disturbance travels in the direction of coastally trapped waves but with a relatively slow propagation speed. When a submarine canyon extends offshore from the estuary, the joint effect of baroclinicity and bottom relief provides forcing for barotropic flow. The disturbance now propagates along the shelf at the first coastally trapped wave mode phase speed, and the shelf circulation is significantly more energetic and barotropic than in the case without the canyon. For both the experiments with and without a canyon an anticyclonic circulation is formed off the mouth of the estuary, generated by the surface outflow and deeper inflow over changing bottom topography. As the deeper inflow encounters shallower depth, the column of fluid is vertically compressed, thereby spinning up anticyclonically due to the conservation of potential vorticity. This feature is in qualitative agreement with the Tully eddy observed off Juan de Fuca Strait. A study of the reverse estuary (where the estuarine water is denser than the oceanic water) shows that this configuration has more potential energy available for conversion to kinetic energy than the normal estuary. Bass Strait may be considered as a possible reverse estuary source for the generation of coastally trapped waves. Model solutions are compared with field observations in the Bass Strait region and with the results of the Australian Coastal Experiment. The effects of a wider shelf and a wider estuary are examined by two more experiments. For the wider shelf, the resulting baroclinic flow is similar to that of the other runs, although the barotropic flow is weaker. The wide estuary model proves to be the most dynamic of all, with the intensified anticyclonic circulation now extending well into the estuary. In the second problem the effect of the horizontal structure of midlatitude oceanic heating on the stationary atmospheric response is examined by means of a continuously stratified model and a simple two level model, both in the quasigeostrophic β-plane approximation. Solutions are obtained for three non-periodic zonal heating structures (line source, segmented cosine, and segmented sine). Little difference is observed between the solutions for these two different models (continuously stratified and two level). There are two cases which emerge in obtaining analytic solutions. In case 1, for large meridional wavenumbers, there exists a large local response and a constant downstream response. In case 2, for small meridional wavenumbers, the far field response is now sinusoidal. A critical wavenumber separating these two cases is obtained. The effect of oceanic heating on the atmosphere over the Kuroshio region is examined in an attempt to explain the large correlations observed between winter Kuroshio oceanic heat flux anomalies, and the winter atmospheric surface pressure and 500 & 700 mb geopotential heights, both upstream and downstream of the heating region. In both models, the response is consistent with the observed correlations. When western North Pacific heating and eastern North Pacific cooling are introduced into the models, a large low pressure response is observed over the central North Pacific. This feature is in excellent agreement with the observed correlations. A time dependent, periodic, two level model (with and without surface friction) is also introduced in order to study the transient atmospheric response to oceanic heating. The height at which the thermodynamic equation is applied is found to be crucial in determining the response of this model. When the heating is entered into the model near to the surface, unstable modes are prevalent sooner than they would be when the heat forcing is applied at a higher level. As in the steady state models, two cases dependent on the meridional wavenumber ɭ emerge in the analysis. For small scale meridional heating structures (large ɭ), the response consists of an upper level high and a lower level low which propagate eastward with time. For large scale meridional heating structures (small ɭ) the response essentially consists of a wavenumber 3-4 perturbation superimposed on the solution for large ɭ. / Science, Faculty of / Mathematics, Department of / Graduate
194

Combined land/sea surface air temperature trends, 1949-1972

Chen, Robert Steven January 1982 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1982. / Microfiche copy available in Archives and Science / Vita. / Bibliography: leaves 120-127. / by Robert Steven Chen. / M.S.
195

Climate predictability and simulation with a global climate model.

Robock, Alan David January 1977 (has links)
Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / Microfiche copy available in Archives and Science. / Vita. / Bibliography : leaves 206-218. / Ph.D.
196

Upper ocean upwelling, temperature, and zonal momentum analyses in the western equatorail [sic] Pacific [electronic resource] / by Robert William Helber.

Helber, Robert William, 1967- January 2003 (has links)
Includes vita. / Title from PDF of title page. / Document formatted into pages; contains 119 pages. / Thesis (Ph.D.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The air-sea interaction thermodynamics of the western equatorial Pacific, the Earth's largest region of warm SST, is a major component of the global climate system. Along the equator, warm pool thermodynamics and momentum are influenced by equatorial ocean visco-inertial boundary layer dynamics that occur within a few degrees of the equator because of the sign reversal of the Coriolis force. Designed to study this system, COARE Enhanced Monitoring Array (EMA) observations of temperature, salinity, velocity, and surface meteorology were centered at 0, 156°E from February 1992 through April 1994. They sampled variability on the equator over larger space/time-scales than the concurrent Intensive Flux Array (IFA) centered at 2°S, 156°E. The EMA data are examined within the context of the larger scale equatorial Pacific and the El Niño conditions that occurred at that time. / ABSTRACT: There is a structural change in the equatorial Pacific near the dateline resulting from the winds that are strong, steady, and easterly in the east and generally weak, punctuated by westerly wind bursts, in the west. East of the dateline the EUC's speed and transport increases downstream, while in the west it tends to be zonally uniform, consistent with the extra-tropical ocean interior water pathways that tend to converge on the equator east of the dateline. At 0°, 156°E in the western Pacific deep, seasonal upwelling (appearing stronger after the peak of the 1991/92 El Niño than during the following weaker El Niño year) occurs within the thermocline in boreal summer with magnitudes as large as upwelling in the eastern Pacific cold tongue. This large upwelling is associated with large downward turbulent heat flux and large turbulent shear stress. / ABSTRACT: While the inferred mixing is quantitatively inconclusive because of unresolved potential errors, it is consistent with the visco-inertial boundary layer concepts from early theory [e.g. Arthur 1960; Robinson 1960; Stommel 1960; and Charney and Spiegel 1971]. These findings suggest that the equatorial thermodynamics differ from those of the IFA. Further process experimentation is necessary to quantify these results. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
197

The behavior of the near ocean surface under the combined action of waves and currents in shallow water

Youssef, Mohamed Mohamed. January 1993 (has links)
Thesis (Ph. D.)--University of Rhode Island, 1993. / Includes bibliographical references (leaves 173-181).
198

Coastal ocean response to alongshore variations in topography and wind forcing /

Castelao, Renato Menezes. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 195-211). Also available on the World Wide Web.
199

The effects of rainfall on temperature and salinity in the surface layer of the equatorial Pacific

Bahr, Frederick L. 19 July 1991 (has links)
Measurements of temperature and salinity in the upper 5 m of the ocean along the equator showed cool fresh anomalies due to rain showers. The measurements were made between 140 W and 110 W during April 1987, an El Nino year. The eastern equatorial Pacific was characterized by weak winds (3 m/s average), high rainfall (1.6 cm/day), and warm surface temperatures (28.4 C). Measurements of temperature were made from a catamaran float at 0.5 and 1 m depth and at 5 m depth from the ship. Salinity was measured at a depth of 1 m from the float and 5 m from the ship. The float was towed off of the port side of the ship outside of the bow wake. Near-surface low temperature and low salinity anomalies due to cool rainfall were encountered. These anomalies were on average cool and fresh by 0.02 C and 0.2 PSTJ with maximum values of 0.5 C and 1.6 PSU. The horizontal extent of the anomalies ranged from less than 10 to more than 100 km. Rainfall depths estimated from salt conservation agreed roughly with shipboard rain-gauge measurements. The characteristic lifetime of the anomalies, estimated from the ratio of the average rain depth to average rain rate, was about 10 hrs. Rainfall temperatures were computed from the T-S mixing curves for three large, newly-formed anomalies. The average rainfall temperature was 21 C. Ocean buoyancy fluxes estimated for intense rain showers were an order of magnitude larger than the fluxes in the absence of rain. / Graduation date: 1992 / Best scan available for p.15-16, 35. Original is a black and white photocopy.
200

Impact of sea surface temperature anomalies to eastern African climate

Unknown Date (has links)
"The main objective of this study is to examine the influence of global SSTAs [sea surface temperature anomalies] on rainfall over eastern Africa (Fig. 1) using Florida State University T21 Global Spectral Model (FSUT21GSM) during the southern hemisphere summer of 1982 (wet year) and 1983 (dry year) (Fig. 2)"--Leaf 3. / Typescript. / "Summer Semester, 1991." / "Submitted to the Department of Meteorology in partial fulfillment of the requirements for the degree of Master of Science." / Advisor: T. N. Krishnamurti, Professor Directing Thesis. / Includes bibliographical references.

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