Experimental Evaluation of Theoretical Formulations for the Correction of Spectral Widths of MST Radar Spectra

Kumar, Shridhar; Rao, T. Narayana; Rao, M. Durga; Patra, Amit

doi:10.1109/tgrs.2020.3026059

Cited by 6 publications

(3 citation statements)

References 26 publications

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“…Nevertheless, the observed spectral broadening contains non‐turbulent contributions along with the required turbulence contribution. The variance of Doppler spectrum due to turbulence,

σ_{turb}^{2}

can be obtained by correcting the observed spectral with for beam and shear broadening as follows (Kumar et al., 2020; Nastrom, 1997).

σ_{turb}^{2} = σ_{obs}^{2} - \frac{θ^{2}}{4 l n 2} [(\cos^{2} α U^{2} badbreak+ V^{2}) - 2 \cos α \sin^{2} α U (U_{z} R) + \sin^{4} α {(U_{z} R)}^{2}]

where

σ_{obs}^{2}

is the observed spectrum width, θ is the one‐way half‐power half‐width of the beam, α is the off‐zenith angle, U and V are the zonal and meridional wind components,

U_{z} = \frac{d U}{d z}

, and R is the range.…”

Section: Methodsmentioning

confidence: 99%

“…The existing antenna array has been configured in the form of 64 sub‐arrays each having 16 antennae (4 × 4 yagi) (black dashed lines in Figure 1a) and these sub‐arrays can be combined into various sizes (from 4 × 4 to 32 × 32) based on user requirement and experiments (Kumar et al., 2020). In principle, each sub‐array can be connected to a receiver, making it a 64 channel receiver system.…”

Section: Multi‐channel Receving System Of Airmentioning

confidence: 99%

“…Nevertheless, the observed spectral broadening contains non-turbulent contributions along with the required turbulence contribution. The variance of Doppler spectrum due to turbulence, 2 turb E  can be obtained by correcting the observed spectral with for beam and shear broadening as follows (Kumar et al, 2020;Nastrom, 1997).…”

Section: Doppler Spectrum Width (σ) Estimationmentioning

confidence: 99%

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Multi‐Receiver Augmentation to Advanced Indian MST Radar (AIR)—Implementation of Spaced Antenna Technique

Kumar

Rao

et al. 2021

Radio Science

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Newly acquired multi‐receiver capability of Advanced Indian MST radar has been utilized to implement the spaced antenna (SA) technique for profiling of winds and turbulence. Two experiments were conducted. In Experiment 1, in addition to the traditional Full Correlation Analysis (FCA), SA analysis is also performed on off‐vertical beam measurements (hereafter Oblique Spaced Antenna [OSA]) and the products are evaluated against those retrieved with Doppler Beam Swinging (DBS) and collocated GPS radiosonde. In Experiment 2, the dependence of height coverage on antenna aperture is examined. The synchronization and phase matching of receiving channels are found to be well within the designed values. The consensus averaged zonal and meridional wind velocities obtained by FCA and OSA compare very well with DBS and radiosonde measurements with correlation coefficients >0.85 and root mean square error (RMSE) < 2 ms−1. The mean value of antenna parameter, ah, extracted from correlation of different antenna pairs compare well with the theoretical estimate. The efficacy of ah in quality controlling the SA derived winds has been examined. Imposing ah condition has certainly removed several outliers and reduced the RMSE (relative to reference) considerably, but it also reduced useful data by 50%. The consensus averaging of winds is found to be more effective in removing outliers and reducing the RMSE. The wind variances estimated by DBS (after accounting the non‐turbulent contributions) and SA agree quite well with a correlation coefficient of 0.95. Utilization of a bigger array increased the height coverage from 10‐12 to 20 km.

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“…Nevertheless, the observed spectral broadening contains non‐turbulent contributions along with the required turbulence contribution. The variance of Doppler spectrum due to turbulence,

σ_{turb}^{2}

can be obtained by correcting the observed spectral with for beam and shear broadening as follows (Kumar et al., 2020; Nastrom, 1997).

σ_{turb}^{2} = σ_{obs}^{2} - \frac{θ^{2}}{4 l n 2} [(\cos^{2} α U^{2} badbreak+ V^{2}) - 2 \cos α \sin^{2} α U (U_{z} R) + \sin^{4} α {(U_{z} R)}^{2}]

where

σ_{obs}^{2}

is the observed spectrum width, θ is the one‐way half‐power half‐width of the beam, α is the off‐zenith angle, U and V are the zonal and meridional wind components,