Radar Research on the Atmospheric Boundary Layer

Gossard, Earl E.

doi:10.1007/978-1-935704-15-7_35

Cited by 95 publications

(80 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(Airborne and tower measurements have provided much evidence that wind-profiler measurements are generally reliable (see, for example, the review by Gossard [1990]). Airborne and tower measurements, however, are always "point measurements," while radar measurements always provide volume averages, which makes the interpretation of a comparison always difficult; second, it is practically almost impossible to operate an in situ probe within the radar resolution volume without severely contaminating the radar data.)…”

Section: Introductionmentioning

confidence: 99%

First synthesis of wind‐profiler signals on the basis of large‐eddy simulation data

Muschinski¹,

Sullivan²,

Wuertz³

et al. 1999

Radio Science

View full text Add to dashboard Cite

Abstract. Radar wind profilers detect scatter from clear-air refractive-index irregularities. The Doppler shift calculated from the time series of the backscattered signal provides an estimate of the radial velocity of the air within the radar's resolution volume. It is known that there are quite a number of effects that can give rise to intrinsic biases in these radial-velocity estimates. It is extremely difficult to unambiguously identify these biases on the basis of observations since it is impossible to independently probe the threedimensional, time-dependent fine structure of the relevant atmospheric variables (wind and refractive index) within the radar's resolution volume down to the relevant spatial and temporal scales associated with the scattering process itself. In this paper the large-eddy simulation (LES) technique is used to generate, with high spatial and temporal resolution where X is the radar wavelength [e.g., Doviak and Zrnid, 1984, 1993;Muschinski, 1998]. That is, as long as Rayleigh scatter does not play a role, wind profilers see only refractive-index structures at the Bragg wave 1437

show abstract

Section: Introductionmentioning

confidence: 99%

First synthesis of wind‐profiler signals on the basis of large‐eddy simulation data

Muschinski¹,

Sullivan²,

Wuertz³

et al. 1999

Radio Science

View full text Add to dashboard Cite

show abstract

“…The dissipation rate can be estimated with several methods, for sonic anemometers (Kaimal et al, 1968;Champagne, 1978;Oncley et al, 1996), ultra-high-frequency WPRs (Gossard, 1990;Jacoby-Koaly et al, 2002), and Doppler wind lidars (Smalikho and Banakh, 2013). The foundational work by Kolmogorov (1941) provided a basic dimensional argument for relating the dissipation rate to the transfer of kinetic energy between scales of motions, assuming isotropic, homogeneous, stationary turbulence.…”

Section: Dissipation Rate Calculationsmentioning

confidence: 99%

“…where σ 2 s is the variance due to wind shear and beambroadening effects, and σ 2 t is due to turbulence (Gossard, 1990). Nastrom (1997) has determined the shear and beambroadening term to depend on the mean wind transverse to the beam axis, V T , the mean wind shear, du/dz, and the antenna properties.…”

Section: ε From Radar Spectral Widthsmentioning

confidence: 99%

“…Turbulence intensities (velocity fluctuations divided by the mean velocities) using refractive index and TKE dissipation rates using spectral widths of the Doppler velocity spectrum were introduced therein, but Cohn (1995) showed that the TKE dissipation rates were more accurately measured by the WPR than the turbulence intensity. Since then, much progress has been made to improve spectral width measurements for dissipation rate estimations through the removal of non-turbulent broadening effects from wind shear and antennae geometry (Gossard, 1990;Nastrom, 1997;Nastrom and Eaton, 1997;White et al, 1999). The full integration of the method into routine use has not taken place, however, due to unidentified limitations in the method's ability to measure the full range of dissipation rates resolved by highfrequency instrumentation, such as sonic anemometers or hot-wire anemometers (Oncley et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improved observations of turbulence dissipation rates from wind profiling radars

2017

View full text Add to dashboard Cite

Abstract. Observations of turbulence dissipation rates in the planetary boundary layer are crucial for validation of parameterizations in numerical weather prediction models. However, because dissipation rates are difficult to obtain, they are infrequently measured through the depth of the boundary layer. For this reason, demonstrating the ability of commonly used wind profiling radars (WPRs) to estimate this quantity would be greatly beneficial. During the XPIA field campaign at the Boulder Atmospheric Observatory, two WPRs operated in an optimized configuration, using high spectral resolution for increased accuracy of Doppler spectral width, specifically chosen to estimate turbulence from a vertically pointing beam. Multiple post-processing techniques, including different numbers of spectral averages and peak processing algorithms for calculating spectral moments, were evaluated to determine the most accurate procedures for estimating turbulence dissipation rates using the information contained in the Doppler spectral width, using sonic anemometers mounted on a 300 m tower for validation. The optimal settings were determined, producing a low bias, which was later corrected. Resulting estimations of turbulence dissipation rates correlated well (R 2 = 0.54 and 0.41) with the sonic anemometers, and profiles up to 2 km from the 449 MHz WPR and 1 km from the 915 MHz WPR were observed.

show abstract

“…Beam broadening depends on the half power width h of the main beam of the antenna radiation pattern and on the horizontal wind speed (Gossard, 1990):…”

mentioning

confidence: 99%

VHF radar observations of turbulent structures in the polar mesopause region

Czechowsky¹,

Rüster²

1997

Ann Geophysicae

View full text Add to dashboard Cite

Abstract. The mobile SOUSY VHF Radar was operated in the summer of 1987 during the MAC/SINE campaign in northern Norway to study the polar mesosphere summer echoes (PMSE). Measurements of the spectral width indicate that two types of structures occur. In general mesospheric layers are bifurcated exhibiting a narrow spectral width and a well-de®ned aspect sensitivity. However, for about 10% of the observation time cells of enhanced turbulence characterized by extremely broad spectral widths appear predominantly in the upper sublayer above 86 km. Identi®cation and separation of beam and shear broadening allows a determination of the turbulence-induced component of the spectral width. This case study reveals that during several events these cloud-like structures of enhanced turbulence move with an apparent velocity of several tens of meters per second which is almost identical with the phase trace velocity of simultaneously observed waves. Since, at that time, the Richardson number was less than a quarter, it was concluded that these turbulent cells were generated by a Kelvin-Helmholtz mechanism. The horizontal extent of these structures was calculated to be less than 40 km. A general relation between spectral width and echo power was not detected. The turbulent component of the spectral width was used to calculate typical values of the energy dissipation rate at times where narrow spectral width dominates and during periods of enhanced turbulence. In addition, the outer scale of the inertial subrange (buoyancy scale) was estimated. For the ®rst time the occurrence and motion of this type of structures of enhanced spectral width is analyzed and discussed in detail.

show abstract

Radar Research on the Atmospheric Boundary Layer

Cited by 95 publications

References 0 publications

First synthesis of wind‐profiler signals on the basis of large‐eddy simulation data

First synthesis of wind‐profiler signals on the basis of large‐eddy simulation data

Improved observations of turbulence dissipation rates from wind profiling radars

VHF radar observations of turbulent structures in the polar mesopause region

Contact Info

Product

Resources

About