Planetary boundary-layer turbulence studies from acoustic echo sounder and in-situ measurements

Bean, B. R.; Frisch, A. S.; McAllister, L. G.; Pollard, J. R.

doi:10.1007/bf02265249

Cited by 15 publications

(5 citation statements)

References 6 publications

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“…This assumption strongly affects the modeling of the atmospheric surface layer. However, beginning with the early observations by Durst (1933), Gifford (1952)) and Lyons et al (1964) and later by, for example, Bean et al (1973)) Kondo et al (1978), Mahrt (1985), and Gossard et al (1985), it is now clear that sporadic outbreaks of turbulence and enhanced vertical diffusion are common in the stable PBL. These effects have not been accounted for in conventional PBL theory and because of this, model predictions of surface fluxes may be underestimated.…”

Section: Introductionmentioning

confidence: 99%

Sporadic breakdowns of stability in the PBL over simple and complex terrain

Nappo

1991

Boundary-Layer Meteorol

129

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Breakdowns of stability in the PBL are examined using one-minute average horizontal wind speeds and temperatures observed over many nights at stations located in simple and complex terrain. The analysis is based on the temporal behavior of the wind speed-temperature covariance, which is obtained by digital bandpass filtering. It is shown that breakdowns are a common feature of the stable PBL over both simple and complex environments. Vertical fluxes of heat during breakdowns are estimated to be a significant fraction of the nighttime average heat flux. It is hypothesized that a major portion of the nighttime vertical transfer of heat, momentum, and atmospheric pollutants occurs during periods of stability breakdowns.

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Section: Introductionmentioning

confidence: 99%

Sporadic breakdowns of stability in the PBL over simple and complex terrain

Nappo

1991

Boundary-Layer Meteorol

129

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“…The atmospheric variables that influence the shape of the Doppler spectrum include the mean vertical temperature an6 vector wind profiles, the three-dimensional turbulent velocity and temperature fields, and finally the angular dependence of the scattering coefficients of all the individual scatterers that contribute to the total received signal. Acdar Doppler measurements have been used to study thermal plume velocities , winds in the planetary boundary layer Beran and Clifford, 1972;Mahoney et al, 1973], gravity waves Beran et al, 1973], and boundary layer turbulence [Bean et al, 1973].…”

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confidence: 99%

Analysis and simulation of phase coherent acdar sounding measurements

Thomson¹,

Coulter²

1974

J. Geophys. Res.

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The phase surface geometry and its dependence upon system and atmospheric parameters for both monostatic and bistatic acdar sounders is discussed. The observed Doppler frequency shift is shown to be a consequence of the motion with respect to the equipbase surfaces of many distributed atmospheric scatterers. Because acdar measured average Doppler frequencies,and Doppler spectra are integral functions of system-related and atmospheric structure-dependent weighting functions, application of simple models that assume signal scattering only along the antenna beam axis may result in significant wind velocity measurement errors. It is further shown that accurate quantitative estimates of Cr: and Cv •' for thin turbulent layers require detailed analysis of the bistatic acdar common volume. Two techniques, based on distributed scatterers and random phasors, respectively, are used for simulating acdar signal phase and amplitude fluctuations.

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“…Recently, the development of various acdar systems has revived interest in using acoustic signals for in particular low-level atmospheric sounding. Observations of planetary boundary layer structure, winds, gravity waves, and turbulence have been made by a number of research groups [see, e.g., McAllister, 1968;Little, 1969;Beran et al, 1971;Beran and Clifford, 1972;Cronenwett et al, 1972;Hooke et al, 1973;Bean et al, 1973].…”

mentioning

confidence: 99%

A method for measurement of temperature profiles in inversions from refractive transmission of sound

Greenfield¹,

Teufel²,

Thomson³

et al. 1974

J. Geophys. Res.

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A method is described for estimating temperature profiles in the lower troposphere during conditions including a surface-based or elevated inversion layer. The method uses acoustic energy transmitted over paths of the order of 10 km in length. Measurements are made at approximately l-kin intervals extending radially outward from the transmitter. The vertical temperature profile is modeled as two constant temperature gradient layers. The first layer extending from the surface to height H1 has a temperature gradient T•' (usually negative upward). The second-layer temperature gradient T2' is strongly positive upward. For temperature profiles of this type, ray paths arrive with a high intensity at a caustic, and no rays return to earth between the source and the caustic. The method requires that H1 be determined by some other means such as vertical acdar sounding. The Ti' and T2' are then simultaneously determined by measuring the range to the caustic and the wave propagation time. Even if the propagation time cannot be measured, useful estimates of T•' can be obtained from observations of H1 and the caustic distance. For a

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Planetary boundary-layer turbulence studies from acoustic echo sounder and in-situ measurements

Cited by 15 publications

References 6 publications

Sporadic breakdowns of stability in the PBL over simple and complex terrain

Sporadic breakdowns of stability in the PBL over simple and complex terrain

Analysis and simulation of phase coherent acdar sounding measurements

A method for measurement of temperature profiles in inversions from refractive transmission of sound

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