• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1743
  • 162
  • 160
  • 160
  • 160
  • 160
  • 160
  • 157
  • 107
  • 61
  • 59
  • 52
  • 23
  • 12
  • 8
  • Tagged with
  • 3528
  • 1163
  • 973
  • 815
  • 522
  • 487
  • 380
  • 268
  • 237
  • 224
  • 204
  • 203
  • 183
  • 179
  • 177
  • 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.
81

the Quantitative Display of Radar Weather Patterns on a Scale of Grey.

Legg, Thomas H. January 1960 (has links)
At 100 miles range, radar can detect variations of 10^4 in rainfall intensity; the signals cover 64 db in power of which many radars can display less than 16 db at a time. Equipment has been designed and studied which displays successive factors of signal power, corrected in a known way for distance, as equally discernible steps of grey. One gain control adjusts the factors to display at a given time all or a chosen fraction of the 64 db. [...]
82

a Dynamical Study of the 1958-59 Stratospheric Polar Vortex.

Boville, Byron W. January 1961 (has links)
The circulation of the stratosphere and its relation to the troposphere is presented for the six-month period October, 1958 to March, 1959. The study is based mainly on circumpolar analyses at five-day intervals at the 500-mb, 100-mb and 25-mb levels, supported by numerous space and time sections. Fourier analysis of the circumpolar charts is used to compute energies and energy exchanges after the manner of Lorenz (1955) and unstable wave characteristics following the linear theory of Fleagle (1957). [...]
83

The Climatology of Rossby Wave Packets Using Object-based Tracking Techniques

Souders, Matthew B. 18 April 2015 (has links)
<p> This research produces an objective, track-based climatology of Rossby wave packets (RWPs) and tests the sensitivity of the results to changes in the methods used in filtering the raw data and in tracking. NCEP/NCAR Reanalysis wind and geopotential height data at 300 hPa every 6 hours were spectrally filtered using a Hilbert transform technique under the assumption that RWPs propagate along a waveguide defined by the 14-day running average of the 300 hPa wind. After some spatial smoothing, the local maxima in RWP envelope amplitude (WPA) were tracked using two objective techniques: a point-based cost optimization routine and a hybrid of point identification and object-based tracking following rules similar to those used in the tracking of tropical convective clusters. The total energy flux term of the eddy kinetic energy equation was used as a cross-check for the purpose of hand-verifying RWP tracks in order to compare the performance of each tracking method. Track data and object-based descriptive statistics (including area, average intensity, intensity volume, intensity-weighted centroid position and velocity) were gathered to describe the inter-annual, annual, seasonal, and regime-based climatology of RWPs. </p><p> When tracking methods are verified over two winter seasons and compared, the hybrid technique statistically outperforms point-based tracking, particularly when estimating track duration and propagation. When long lived RWPs are verified, there is strong evidence that some RWPs can last over 30 days and circumnavigate the Northern (Southern) Hemisphere up to two (three) times. RWPs are found to exhibit a much more pronounced seasonal cycle in the Northern Hemisphere, where they are nearly non-existent in the summer months (JJA), as compared to nearly continuous RWP activity downwind of South Africa during Austral Summer (DJF). Interannual variability in packet frequency and intensity in the Northern Hemisphere is found to be strongly connected with the large scale flow regime, with oscillatory patterns like ENSO and the AO playing significant roles. Enhanced WPA is also found to coherently propagate in composites of regime change events (e.g. a reversal of the AO). No significant long-term changes in RWP frequency or intensity are found; however, the North Pacific storm track appears to have shifted northward in the last thirty years. </p>
84

Radar attenuation estimates from raingauge statistics.

Hamilton, Paul. M. January 1960 (has links)
The attenuation of radar weather signals by intervening precipitation is difficult to estimate by radar methods. Rainfall rates observed at a point in the path of a storm approximate those along a section through the storm; this is the basis in estimating attenuation frequencies at 3.2 cm wavelength for a summer’s storms at Montreal. It has been found that attenuation along a radar path increases with increasing target intensity: expected attenuation over a 30 mi path at 3 mm hr-1 is 3 db, at 80 mm hr- 1 is 14 db. Power can overcome the limitations imposed by attenuation upon the radar as an indicator of the presence or absence of precipitation. But quantitative observations are difficult; and so attenuation gravely limits the 3.2 cm wavelength radar in a role as a severe-storm indicator.
85

The stratospheric wind regimes of the 1958-59 winter.

Steiner, Harold. A. January 1961 (has links)
Vertical cross sections along the 80W meridian from the surface to 35 km (circa 5 mb) are presented for each fifth day of the 1958-1959 winter season. The synoptic features of the stratosphere as shown by the cross sections - are discussed in monthly résumés in sufficient detail to furnish a generalized picture of the seasonal changes. An objective method for determining the peak winds in jet streams is formulated and results from this method compare favourably with meso-scale data from aircraft probes. The baroclinity of the troposphere and lower stratosphere and its relation to the Ferrel westerlies are discussed. Boundary conditions for the crests of the Ferrel westerlies on summer and winter type wind profiles are presented and shown to be quasipermanent in nature.
86

A synoptic climatology for British Columbia: some effects of mountainous terrain on observed weather.

Walker, Edward. R. January 1961 (has links)
The problem was to explain effects of mountain terrain, the Canadian Cordillera, on distributions of precipitation and temperature. Techniques from several fields of meteorology were blended with modern data processing in an attempt to overcome the sparseness and non-representativeness of weather observations. Atmospheric characteristics over British Columbia were found to be sharply differentiated by the direction of the flow at the 700 millibar level. Linearized two-dimensional mountain airflow theory was combined with relevant atmospheric characteristics to derive simple models of precipitation distributions over mountain ranges. These models were used to supplement observations to obtain improved charts of precipitation over the southern half of British Columbia. Altitudinal variation, and other characteristics of the distributions of precipitation and temperature not hitherto available were elucidated. The relationships obtained between atmospheric characteristics and observed weather suggest that it may be practicable and economical to observe the climate of sparsely settled mountainous areas using relatively few weather stations.
87

Statistical methods in the forecasting of meteorological pressure fields over the southern hemisphere.

Bull, Anthony James. January 1969 (has links) (PDF)
Thesis (Ph.D. 1970) from the Dept. of Statistics, University of Adelaide.
88

Polar substorm phenomena at Macquarie Island.

Yuan, Frederick Fan Fu. January 1970 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Mawson Institute for Antarctic Research, 1971.
89

Characterization of episodic rip current pulsations in the inner shelf during RCEX 2007

O'Neill, Andrea C. January 2009 (has links) (PDF)
Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, March 2009. / Thesis Advisor(s): MacMahan, Jamie. "March 2009." Description based on title screen as viewed on April 23, 2009. Author(s) subject terms: Rip currents, rip current structure, episodic rip current pulsations, inner shelf, RCEX 2007, surf zone volume exchange, Sand City, nearshore circulation Includes bibliographical references (p. 45-48). Also available in print.
90

Coastal jets and their interactions along the central California coastline

Lynam, Liam J. January 2009 (has links) (PDF)
Thesis (M.S. in Meteorology)--Naval Postgraduate School, March 2009. / Thesis Advisor(s): Nuss, Wendell A. "March 2009." Description based on title screen as viewed on May 7, 2009. Author(s) subject terms: Coastal Jet, Froude number, gap flow, barrier jets, Monterey, windstorm Includes bibliographical references (p. 65-68). Also available in print.

Page generated in 0.0312 seconds