• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 235
  • 55
  • 36
  • 14
  • 14
  • 14
  • 14
  • 14
  • 14
  • 9
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 437
  • 70
  • 67
  • 54
  • 48
  • 48
  • 44
  • 42
  • 41
  • 39
  • 38
  • 35
  • 31
  • 27
  • 27
  • 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.
211

Optical studies of the mesospheric region

Woithe, Jonathan Mark January 2000 (has links)
A three-field photometer has been employed at the University of Adelaide's Buckland Park field site to collect optical observations of the 557.7nm OI and 730nm OH airglow emissions. Data have been collected on an almost continuous basis since May 1995 through to May 2000, with observations made whenever the moon was not up. Techniques and analysis procedures have been developed which allow routine extraction of the parameters of gravity waves observed each night. A cross-spectral analysis was performed on processed data from the photometer to identify short period (less than 3 hours) wave activity on nights where the impact of clouds on the data was minimal. The resulting wave parameters are analysed for seasonal variability and used to build up a climatology of wave parameters over the 5 years of observation. No consistent seasonal variation was observed, although there was a strong eastward perference to the wave's propagation direction. Implications of this finding are discussed. A co-located MF radar has been operating in spaced antenna mode providing wind data concurrent with the optical observations for most of the acquisition period. When available the wind data allowed calculation of the intrinsic parameters for waves identified in the optical data. The seasonal variablility of these parameters was investigated. An evaluation of energy and momentum fluxes estimated using the method of Swenson et al (1998b) was carried out. Approximations made in this method were found to be inappropriate for the waves detected by the photometer, and a refined procedure was therefore developed. This gave more realistic results, although large number of physically unreasonable momentum flux measurements were reported. Possible reasons for these were explored, and the need for further investigations emphasised. The five year dataset also allowed investigation of the long-term behaviour of the airglow. Both the intensity and variance were analysed using the Lomb-Scargle method across the complete dataset to identify the dominant periods present. Following similar treatment, the MF spaced antenna winds were compared with the optical results; this utilised a complex spectrum extension to the basic Lomb algorithm. Seasonally related periodicities of two years, one year, one half of a year and one third of a year were observed in the optical data, along with a possible signature of a five and a half year period potentially linked to the eleven year solar cycle. The radar data did not have stong signatures of the one third of a year periodicity although the presence of an five and a half year periodicity could not be ruled out. Gravity wave activity, as measured by the optical intensity variance, reached a maximum during autumn with a secondary maximum occurring in spring. The annual variability of the wave spectrum detected by the photometer was also studied which showed a falloff in the wave energy at short periods (less than thirty minutes) during autumn and spring. This suggested that the enhanced wave activity at these times consisted mainly of waves with periods greater than thirty minutes. / Thesis (Ph.D.)--Department of Physics and Mathematical Physics, 2000.
212

Dynamics of the thermosphere over Mawson, Antarctica /

Wardill, P January 1988 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Mawson Institute, 1989. / Includes bibliographical references (leaves 140-151).
213

Dynamics of the Antarctic mesosphere and lower thermosphere /

Phillips, A January 1989 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Mawson Institute for Antarctic Research, 1990. / Copies of author's previously published articles inserted. Includes bibliographical references (leaves 219-226).
214

A numerical study of the mesoscale eddy dynamics of the Leeuwin Current system /

Meuleners, Michael Joseph. January 2005 (has links)
Thesis (Ph.D.)--University of Western Australia, 2007.
215

Modeling the effect of eddies and advection on the lower trophic ecosystem in the northeast tropical Pacific

Samuelsen, Annette. O'Brien, James J. January 2005 (has links)
Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. James J. O'Brien, Florida State University, College of Arts and Sciences, Dept. of Oceanography. Title and description from dissertation home page (viewed June 8, 2005). Document formatted into pages; contains xiii, 87 pages. Includes bibliographical references.
216

Wind effect on shallow bodies of water with special reference to Lake Okeechobee /

Kivisild, Hans R. January 1954 (has links)
Thesis--Tekniska högskolan, Stockholm, 1954. / Extra t.p., with thesis statement, inserted. Includes bibliographical references (p. 137-142).
217

Observation and tracking of tropical cyclones using resolution enhanced scatterometry /

Halterman, R. Ryan January 2006 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2006. / Includes bibliographical references (p. 83-85).
218

Variation of the drag coefficient with wind and wave state

Byars, Beverly J. January 1985 (has links)
Thesis (M.S.)--Naval Postgraduate School, 1985. / Cover title. "September 1985." Includes bibliographical references (p. 104-108).
219

An empirical statistical model relating winds and ocean surface currents : implications for short-term current forecasts /

Zelenke, Brian Christopher. January 2005 (has links)
Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 83-86). Also available on the World Wide Web
220

Wind and turbulence structure in the boundary layer over the Antarctic Plateau

Dabberdt, Walter F. January 1969 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Page generated in 0.0308 seconds