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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.
21

Air-sea flux parameterisations in a shallow tropical sea

Schulz, Eric Werner, mathematics, UNSW January 2002 (has links)
This thesis is a study of the air-sea fluxes of momentum, sensible heat and latent heat. Fluxes are estimated using the covariance, COARE2.6b bulk flux algorithm, and inertial dissipation methods. The bulk algorithm is validated against the covariance fluxes for the first time in a light-wind, shallow tropical sea, with strong atmospheric instability and low sea state conditions. The removal of ship motion contamination is investigated. This is the first study to quantify the errors associated with corrections for ship motion contamination, and the effects of motion contamination on the covariance calculated heat fluxes. Flow distortion is investigated. Bulk transfer coefficients and roughness lengths are computed and related to the sea state. Ship motion contamination is successfully removed in 86% of the runs. Error analysis of the motion removal algorithm indicates maximum uncertainties of 15% in the wind fluctuations, and 0.002 N/m/m for the wind stress. Motion correction changes the stress by more than 15% in half of the runs analysed. The ship is found to accelerate the mean air flow and deflect it above the horizontal. A correction is developed for the air flow acceleration. The scalar fluxes show good agreement on average for all the methods. As wind speed approaches zero, covariance wind stress is significantly larger than the bulk and inertial dissipation derived wind stress. The non-zero covariance wind stress is reflected in the drag coefficient, CdN10, and momentum roughness length, z0, which are much larger than the parameterisations used in the bulk algorithm. The MCTEX CdN10, wind speed (u10N) relation is 1000 x Cd10N = 1.03 + 7.88/(u10N)^2 0.8 &lt u10N &lt 7.5 m/s z0 is primarily a function of wind speed rather than sea state, with largest roughness lengths occurring as wind speed approaches zero. This relation is used in the bulk algorithm, yielding good agreement between covariance and bulk derived wind stress. A new parameterisation for the effects of gustiness, based on wind variance is developed. This brings the bulk wind stress into agreement with the covariance derived wind stress.
22

Ocean-atmosphere interaction in the seasonal to decadal variations of tropical Atlantic climate

Okumura, Yuko. January 2005 (has links)
Thesis (Ph. D.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 135-148).
23

Evolution of boundary layer height in response to surface and mesoscale forcing /

Moore, Matthew J. January 2005 (has links) (PDF)
Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): Qing Wang. Includes bibliographical references (p. 57-58). Also available online.
24

A case study of insitu-aircraft observations in a waterspout producing cloud

Baskin, Clayton M. 03 1900 (has links)
Approved for public release, distribution is unlimited / An analysis of in-situ aircraft observations collected in the parent cloud of a waterspout is presented. Previous waterspout studies were confined mainly to photometric and model simulated data, no in-situ observations were made internal to the parent cloud. On 27 June 2002 the Cooperative Institute for Remotely Piloted Aircraft Studies (CIRPAS) UV-18A Twin Otter aircraft collected observations in a cloud that had developed in a cloud line, located approximately 15km south of Key West, and that formed a waterspout. This study attempts to analyze the waterspout formation process using these data and through a series of scale interactions, from the synoptic scale down to the individual cloud scale. Based upon the analyzed data a hypothetical formation process is developed. The background synoptic scale flow is shown to establish the necessary ambient shear as a key factor in the waterspout formation. The orientation of mesoscale convergent boundaries and thermodynamic processes, internal to the cloud, proved to be an essential factor in developing the vertical motion patterns necessary for formation of an organized circulation in the shear region and to provide the tipping and stretching of the resultant vortex necessary to account for the waterspout formation. This is consistent with conclusions derived from previous studies. / Captain, United States Air Force
25

A dynamic program for minimum cost ship routing under uncertainty

Chen, H. (Henry) January 1978 (has links)
Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Ocean Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by H.T. Chen. / Ph.D.
26

Decadal variability of the Pacific subtropical cells and equatorial sea surface temperature

Young, Carina Saxton 17 November 2009 (has links)
This thesis investigates possible dynamical pathways through which variability in the extra-tropical Pacific Ocean influences decadal fluctuations of tropical Pacific sea surface temperatures (SST). Specifically, we examine the hypothesis that low-frequency changes in the Pacific‟s meridional subtropical cells (STCs), which transport subsurface water masses equatorward from the extra-tropical into the tropical Pacific upwelling system, modulate decadal variations of the equatorial SST. The relationship between the STCs and equatorial Pacific SST anomalies is explored statistically using the monthly hindcast output from the Ocean General Circulation Model (OGCM) for the Earth Simulator (OFES). We find that decadal variability of the subsurface heat transport of the southern branch of the STC is more closely correlated (R = -0.74) with eastern equatorial SST anomalies on timescales longer than 8 years. The northern branch of the STC is overall not well correlated with equatorial SSTa; however, we find that in the period before the 1976 climate shift, the northern cell is more strongly and significantly correlated with equatorial SSTa (R = -0.89, >99%), while the southern cell is not (R = -0.32). The physical significance of these findings remain unclear and requires isolating mechanisms that could lead to an asymmetry in the role of the northern and southern STC in modulating eastern equatorial SSTa during different states of the Pacific climate. This will be a critical step to attribute physical significance to the statistical changes observed before and after the 1976 climate shift.
27

Atmospheric freshwater sources for eastern Pacific surface salinity

Tonin, Hemerson Everaldo, January 2006 (has links)
Thesis (Ph.D.)--Flinders University, School of Chemistry, Physics & Earth Sciences. / Typescript bound. Includes bibliographical references: (leaves xx) Also available online.
28

Interannual variability in cloudiness, sea surface temperature, and atmospheric circulation over the midlatitude North Pacific during summer /

Norris, Joel R., January 1997 (has links)
Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (p. 182-199).
29

Yellow Sea thermal structure

Fralick, Charles R. January 1900 (has links)
Thesis (M.S.)--Naval Postgraduate School, 1994. / "September 1994." Includes bibliographical references (p. 77-78).
30

Interannual variability in cloudiness, sea surface temperature, and atmospheric circulation over the midlatitude North Pacific during summer

Norris, Joel R., January 1997 (has links)
Thesis (Ph. D.)--University of Washington, 1997. / Includes bibliographical references (leaves 182-199).

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