• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 901
  • 419
  • 247
  • 114
  • 84
  • 83
  • 30
  • 27
  • 27
  • 27
  • 27
  • 27
  • 27
  • 26
  • 18
  • Tagged with
  • 2171
  • 788
  • 569
  • 450
  • 445
  • 333
  • 235
  • 204
  • 202
  • 144
  • 143
  • 142
  • 134
  • 128
  • 123
  • 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

Parameter Estimations For Locally Coupled Land Surface-Atmosphere Models,

Liu, Yuqiong January 2003 (has links)
As land-surface modeling moves from the off-line mode to the coupled mode, it is also highly desirable to extend the off-line calibration of land-surface models to coupled applications. Using the NCAR SCCM as an example, this study proposed and implemented some effective schemes for the application of automatic parameter estimation procedures in a locally coupled environment, where other relevant issues such as parameterization tests, sensitivity analyses, and off-line calibrations were also involved. A parameterization deficiency having serious negative impacts on the performance of the NCAR SCCM was identified and rectified in this work, which led to significantly improved model performances and formed the basis for the subsequent sensitivity analysis and calibration experiments. To facilitate the calibration studies, an independent sensitivity analysis was conducted to identify some sensitive model parameters, followed by a multi-objective sensitivity analysis using the MOGSA algorithm to obtain better understanding of the model. Some off-line calibrations using the NCAR LSM were also conducted for comparison purposes. In the locally coupled environment, both land-surface and atmospheric variables/parameters were involved in the calibration processes of 14 different predesigned calibration cases. In brief, the results show that atmospheric parameters are of critical importance for the calibration of a coupled land surface-atmosphere model, and atmospheric forcing variables generally contain more useful information for calibration than land-surface fluxes/variables. In the coupled environment, step-wise calibration schemes, with land-surface and atmospheric parameters optimized successively in the off-line and coupled modes, respectively, appear to be superior to the single-step calibration schemes which optimize land-surface and atmospheric parameters simultaneously in the coupled environment, in that the former can provide better converged optimal solutions with less uncertainties. In addition, the results also show that better optimization effects can be achieved in the partially decoupled environment by replacing the model-generated precipitation and net radiation with the corresponding observations to drive the land-surface part of the model, indicating the dominant importance of precipitation and radiation in a coupled land surface-atmosphere model.
22

A direct method for computing radiative flux divergence in an atmospheric model.

Zemel, Hersh January 1966 (has links)
No description available.
23

Atmospheric Kinetic energy at 500 millibars.

Trueman, Mark Edwin Harry January 1968 (has links)
No description available.
24

An analysis of ice storm impacts, warnings, and emergency management response

Call, David A. January 2007 (has links)
Thesis (PH.D.) -- Syracuse University, 2007. / "Publication number AAT 3281754"
25

Parameter Estimations For Locally Coupled Land Surface-Atmosphere Models,

Yu, Yuqiong January 2003 (has links) (PDF)
Thesis (Ph. D. - Hydrology and Water Resources)--University of Arizona, 2003. / Includes bibliographical references (leaves 228-239).
26

Rocket measurements of solar and lunar ultraviolet flux and the determination of atmospheric molecular oxygen and ozone densities.

Ilyas, Mohammad. January 1976 (has links) (PDF)
Thesis (Ph.D.)-- University of Adelaide, Dept. of Physics, 1976.
27

Thermal sulfate reduction as the major cause of the anomalously low rise in Paleoproterozoic oxygen

Loukinova, Natalia. January 2009 (has links) (PDF)
Thesis (M.S. in geology)--Washington State University, May 2009. / Title from PDF title page (viewed on Aug. 10, 2009). "School of Earth and Environmental Sciences." Includes bibliographical references (p. 23-26).
28

Roughness length variability over heterogeneous surfaces

Ellis, Matthew A. January 2010 (has links) (PDF)
Thesis (M.S. in Meteorology)--Naval Postgraduate School, March 2010. / Thesis Advisor(s): Wang, Qing. Second Reader: Nuss, Wendell A. "March 2010." Description based on title screen as viewed on April 26, 2010. Author(s) subject terms: Atmospheric Boundary Layer, Turbulence, Roughness Length, Momentum Flux, Heat Flux, Flus-profile Relationships, Monin-Obukhov Similarity Theory, Heterogeneous Surfaces. Includes bibliographical references (p. 73-75). Also available in print.
29

A critical comparison of two theories of the atmospheric Chandler "pole tibe"

Nash, Eric Robert. January 1982 (has links)
Thesis (M.S.)--University o Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 19-20).
30

Lunar tides in the E-region Kennelly-Heaviside layer

Niblock, Peter A. January 1952 (has links)
A number of Investigators have conducted research on the earth's atmosphere. Among them have been Laplace, Lord Kelvin and Simpson, who were interested, primarily, in pressure variations in the atmosphere; Pekeris and G. I. Taylor, who were Interested in the mechanism of atmospheric resonances; and Balfour-Stewart, Chapman, and Appleton and Weekes, who were interested in upper-atmosphere research. However, all these investigators had one idea in common; they sought to establish the presence of lunar and solar effects upon the earth's atmosphere. Even after the work which has been done on lunar tides in the E-region of the Kennelly-Heaviside layer by Appleton and Weekes and other investigators, there are still questions which remain unanswered on this subject. A description is given of an investigation performed at The University of British Columbia to determine the magnitude of a lunar tide in the E-region of the Kennelly-Heaviside layer. Details are Included of design considerations for a pulse-type communications receiver to operate in the 0.5 to 30 mc/s. band. The main differences between the unit discussed and a standard communications receiver lie in the band-pass, or selectivity characteristics and in the receiver recovery time after shock excitation by very strong radio frequency fields. Also included are details of the transmitting units, the antenna, and the calibration display unit used in the Investigation. Analysis of the data gathered during the investigation showed that there was no tide in the Kennelly-Heaviside layer Region-E of the magnitude or phase of that found by Appleton and Weekes in 1939. An analysis of the data gathered for the lunar tides Investigations produces strong evidence of daytime D-layer ionization between heights of 50 and 85 kilometers. This evidence is discussed and fields for future research are suggested. Comparisons are made between the results of Chapman's analysis of the lunar pressure oscillations at ground level and the accumulated data from the ionospheric lunar tide investigation of Appleton and Weekes and those from this investigation. The data derived from these widely differing sources are shown to be completely compatible. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Page generated in 0.0608 seconds