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Small scale wind structure in the upper atmosphereMcAvaney, Bryant John. January 1970 (has links) (PDF)
No description available.
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An examination of the spectrum for coastal winds on the mesoscaleFrye, Daniel Evan 09 June 1971 (has links)
Wind speed data were taken at a weather station on the coast
and horizontal wind speed energy spectra were computed. The shape
of an average spectrum obtained in marine environment is compared
with an average land spectrum and the presence of a spectral gap is
observed in the shoreline spectrum. Wave number domain spectra
are compared with frequency domain spectra. Strong similarity
between the spectra is found for short periods, but at longer periods
the f-space spectrum localizes most of the energy at specific frequencies,
while the k-space spectrum spreads the energy over many
wave numbers. When the wind speed is fairly constant, Taylor's
hypothesis is found to be a reasonable approximation up to periods
of tens of minutes.
A preliminary investigation of the dependence of the value of
the drag coefficient on the period over which the average wind
is measured was made. A line of the form C[subscript Dx]/C[subscript D₁₀]= .89 + .1 log X
fits the graphed points quite well with a correlation of .98, where X
is the averaging distance in miles. Differences of 20% in the value
of the drag coefficient over averaging distances between 10 and 1600
miles are observed. From this preliminary study, it appears that
a more detailed study of this effect would be worthwhile. / Graduation date: 1972
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The mesoscale wind field during project JASIN 1972Cummings, Timothy K. 16 August 1973 (has links)
The wind field measured during Project JASIN 1972, a joint
British-American venture during September 1972, was analyzed.
These measurements were done, with equipment manufactured by
Ivar Aanderaa of Bergen, Norway, on large, anchored toroid buoys.
The results of the analysis of the wind field, which included
divergence and vorticity estimates and spectral analysis, compared
favorably with results from previous studies by other investigators.
The spectral analysis of the wind field at different locations showed
some differences indicating that ocean wind fields are less homogeneous
than had been expected. Basic statistics of the wind speed and
direction at the same locations also confirmed this conclusion.
An apparent diurnal cycle in the u and v components of the wind
was studied. It was shown that the total wind vector for the study
period was quite different at different horizontal locations while hourly
deviations around these means during a day showed remarkable
similarities.
A curious eight-hour period found in the divergence estimates
on a 100 km grid is possibly related to an eight-hour air pressure wave
studied many years ago by Von Hann (1918) and Bartels (1932).
It was concluded that the wind field over the ocean is not entirely
homogeneous and some rather large differences are found over a scale
as small as 100 kilometers. / Graduation date: 1974
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A statistical study of Oregon coastal windsDetweiler, John Henry 02 February 1971 (has links)
The data recorded between March 3, 1969, and October 31, 1969,
by a wind gauge installed at the South Jetty, Newport, Oregon, were
analyzed. The components of each observation were treated as if they
were an independent, normal, bivariate distribution and standard
statistical procedures were applied. It was found that the wind gauge
is obscured by the land to the southeast and that the adjacent land has
the effect of channeling the wind so that it comes from the north, the
east, and the south.
The seasonal and diurnal wind shifts were observed and described.
It was noted that the orientation of the diurnal shift changed with
time; it rotated clockwise from March to July and counterclockwise
from July to October. / Graduation date: 1971
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The effect of the land breeze on the mesoscale wind field off the Oregon coastPoole, Stephen Lynn 24 June 1974 (has links)
Two land breeze events occurred off the Oregon coast on the
nights of April 19th and 20th, 1973. An array of four moored toroid
buoys and one land station recorded the effect of the land breeze event
on the surface mesoscale wind and temperature fields. The land
breezes may have resulted from the premature summerly conditions
of fair weather and southward coastal winds that were caused by an
early northeastward extension of the North Pacific High.
The main features of the events were as follows:
1) A cooling period of a few hours after sunset established an
air temperature gradient of -0.1° C km⁻¹ in the nearshore 10 km
region.
2) The advance of the land breeze-front produced a 5° C temperature
drop at the land station and a 1° C temperature drop at the buoy
stations.
3) Simultaneously, the front also caused a decrease in wind
speed by about an order of magnitude at each of the stations. During
the passage of the front the wind veered from southward at 10 m sec⁻¹
to westward at 2 to 3 m sec⁻¹.
4) At dawn the temperature gradient was rapidly reversed, but
there was a 2 hour lag before the wind speed began to increase. No
frontal return flow was observed, instead the wind backed to the south
and increased gradually over the array.
Horizontal divergence and vertical vorticity were calculated
using a simplified program. The land breeze produced spans of
positive vorticity (5 x 10⁻⁴ sec⁻¹) over the array, possibly due to the
horizontal wind shear in the offshore direction. The land breeze also
caused a zone of convergence over the nearshore 10 km. The convergence
was preceeded by a brief period of intense divergence.
There was no convergence zone beyond the nearshore region.
Instead there appeared alternating bands of convergence and divergence
with a period of around 37 minutes. The same periodicity was
observed in the offshore wind velocity. These features can be explained
by a model of horizontal roll vortices migrating seaward
from the nearshore convergence zone. The roll wavelength is inferred
to be 4.7 km, the westward migration speed is 2 m sec⁻¹, and
the height of the PBL is estimated to be 1. 5 km. This leads to a
PBL Reynolds number of 370 ± 80, which is lower than previous observations
and suggests that the rolls are produced by buoyancy and
parallel instability. A model which is compatible with all the above
is presented. / Graduation date: 1975
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A study of the variation of the surface roughness lengths at Risø, DenmarkHennessey, Joseph Paul Jr 24 July 1974 (has links)
The Risø data were analyzed for variations in the surface roughness
lengths. The method of analysis was tested on the Wangara data
and proved satisfactory at this homogeneous site.
Annual mean surface roughness lengths were determined for
three wind speed categories and three stability categories. The decrease
in surface roughness length with increasing wind speed and
decreasing stability was large but not generally statistically significant
because of the large dispersion in the data. The annual mean
roughness length varied over several orders of magnitude.
These results and also the ten year mean profiles were compared
with those of previous investigators.
It was found that the standard deviation determined from mean
annual profiles over a ten year period was greater than one order of
magnitude. / Graduation date: 1975
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Diurnal fluctuation of meteorological variables above sloping terrainChan, Michael W. 28 October 1974 (has links)
Surface meteorological data collected at a mesonetwork in
Colorado during the 1973 National Hail Research Experiment were
analyzed to see if a diurnal oscillation of boundary layer wind exists
and also to determine the mechanism that drives the wind system.
The average temperature, pressure, and wind velocity for a month's
time were computed in order to filter out synoptic disturbances.
The analysis of averaged daily potential temperature distribution
shows that, during the study period, air is always stable along
the slope at night and is stable over 75% of the time during the daylight
hours. This implies that nighttime downslope flow is driven by
baroclinity and strongly influenced by frictional effects. This analysis
also shows that differences in horizontal potential temperature are
minimal at the time of day when hail activity is statistically a
maximum.
Hodographs obtained from averaging wind velocities show that
the air flow is upslope during the afternoon and downslope at night.
This type of air movement is attributed to baroclinicity caused by
diurnal heating along a slope.
Spectral analysis of wind speeds at two stations shows
numerous peaks and valleys in various spectra. Several of these
peaks are attributed to diurnal and inertial oscillations. / Graduation date: 1975
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An observational study of the wind fields associated with GATE cloud clustersTollerud, Edward I. 01 June 1983 (has links)
The wind and thermodynamic fields associated with eastern
Atlantic cloud clusters are studied using radiosonde data from
the Global Atmospheric Research Program Atlantic Tropical Experiment
(GATE). These data are from the gridded set of winds prepared
by Dr. Katsuyuki Ooyama (AOML-NOAA) and Dr. Jan-Hwa Chu
(SSEC, University of Wisconsin, Madison) using an objective
analysis scheme designed by Dr. Ooyama. Similarly-analysed
thermodynamic data prepared by Dr. Steven Esbensen (Oregon State
University) are also used.
Case studies of the vorticity budget for the 4 September
squall and the 5 September cluster show significant contributions
by all budget terms including the residual, which is interpreted
as the effects of cumulus convection, mesoscale cloud lines, or
other small-scale circulations. The residual is particularly
large in the boundary layer and upper troposphere. The fields
of winds and vorticity budget terms in the upper troposphere of
the two systems are similar. However, at the level of the mid-tropospheric
jet, the small-scale production of vorticity is
significantly different in the two systems.
A technique for compositing clusters using satellite-derived
cloud-top data is applied to GATE data from Phase 3. Vertical
motions within and below the anvils are in accord with previous
studies. Frictionally-induced inflow is found to be of secondary
importance to the development and maintenance of cluster circulations.
The composited vorticity budget residuals are again large
in the boundary layer and upper troposphere.
A large-magnitude asymmetric vorticity couplet observed in
the upper troposphere of individual clusters and in composite
results is examined. Cluster-scale twisting and motions at meso- or
smaller scales are found to produce the couplet, while cluster-scale
divergence is the primary destructive agent. A deceleration
of the strong easterlies at this level produces these couplets.
Possible mesoscale and cumulus sources of this deceleration are
discussed.
Present schemes that parameterize vorticity production by
cumulus convection are found to be inconsistent with similar
schemes that parameterize momentum production. Furthermore, these
vorticity parameterizations cannot describe the production of the
upper-tropospheric couplets discussed above. An alternate parameterization,
formed by taking the curl of the parameterized momentum
source, does qualitatively describe the couplets. / Graduation date: 1984
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Numerical study on wind field and air pollutant dispersion in urban street canopiesXia, Jiyang. January 2000 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 123-129).
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Studien über die wirkungen des windes in den kalten und gemässigten erdteilen ...Samuelsson, Carl. January 1926 (has links)
Inaug.-diss.--Upsala. / "Reprinted from Bull. of the Geol. institut. of Upsala, v, xx." "Litteraturverseichnis": p. 224-230. Translated by O. Zdansky. of. Einleitung.
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