Atmospheric radar imaging using multiple‐receiver and multiple‐frequency techniques

Yu, Tian-You; Palmer, Robert D.

doi:10.1029/2000rs002622

Cited by 41 publications

(43 citation statements)

References 28 publications

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“…The question of whether MF/HF SA wind fields should be quality controlled is still open, but we would recommend its adoption. The application of more sophisticated experimental techniques such as pulse coding to improve the height coverage at lower heights, improve range resolution, improve duty cycles, and reduce interference is suggested, as are the introduction of range imaging (RIM)-like techniques (e.g., Yu and Palmer 2001), and further exploitation of MF meteor echoes. These developments will continue to extend the technique, as will hardware improvements, which are continuing generally with atmospheric radar.…”

Section: Discussionmentioning

confidence: 99%

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

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The application of medium-frequency (MF) and high-frequency (HF) partial reflection radar to investigate the neutral upper atmosphere is one of the oldest such techniques still regularly in use. The techniques have been continuously improved and remain a robust and reliable method of obtaining wind velocities, turbulence intensities, electron densities, and measurements of atmospheric structure in the mesosphere lower thermosphere (MLT) region (50 to 110 km). In this paper, we review recent developments, discuss the strengths and weaknesses of the technique, and consider possible improvements.

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Section: Discussionmentioning

confidence: 99%

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

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“…In the RIM processing, the Capon method (Palmer et al, 1999), one of the optimization methods, was employed to estimate the range-dependent brightness. Although other optimization methods such as maximum entropy (Yu and Palmer, 2001) and multiple signal classification (Luce et al, 2001) are usable for RIM, the Capon method is simple, less time consuming, and robust for the processing of radar data (Yu and Palmer, 2001). Nevertheless, some deficiencies of the Capon method in spectral analysis were also reported.…”

Section: Range Imaging Technique Of the Chung-li Vhf Radarmentioning

confidence: 99%

“…This is because the case presented in Fig. 1 employed a Gaussian instead of rectangular pulse shape, resulting in a range-weighting function broader than that defined by the standard deviation of 74 m. By contrast, a trapezoid pulse shape that is close to a rectangular shape was employed in case 8, thereby resulting in a value of 80 m for the peak location of σ z , which is not far from the value of 74 m. As for the dependence of the σ z value on SNR, it is not unaccountable because the performance of the Capon method is also SNR-dependent (Palmer et al, 1999;Yu and Palmer, 2001). As the SNR decreases, the RIM brightness becomes less accurate.…”

Section: Different Receiver Systemsmentioning

confidence: 99%

Evaluation of multifrequency range imaging technique implemented on the Chung–Li VHF atmospheric radar

Chen

Tsai

et al. 2016

Atmos. Meas. Tech.

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Abstract. The multifrequency range imaging technique (RIM) has been implemented on the Chung-Li VHF array radar since 2008 after its renovation. This study made a more complete examination and evaluation of the RIM technique to facilitate the performance of the radar for atmospheric studies. RIM experiments with various radar parameters such as pulse length, pulse shape, receiver bandwidth, transmitter frequency set, and so on were conducted. The radar data employed for the study were collected from 2008 to 2013. It has been shown that two factors, the range/time delay of the signal traveling in the media and the standard deviation of Gaussian-shaped range-weighting function, play crucial roles in ameliorating the RIM-produced brightness (or power distribution); the two factors are associated with some radar parameters and system characteristics. The range/time delay of the signal was found to increase with time; moreover, it was slightly different for the echoes from the atmosphere with and without the presence of significant precipitation. A procedure of point-by-point correction of range/time delay was thus executed for the presence of precipitation to minimize the bogus brightness discontinuity at range gate boundaries. With the RIM technique, the Chung-Li VHF radar demonstrates its first successful observation of double-layer structures as well as their temporal and spatial variations with time.

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“…Another form of the weighting matrix can be derived from the Capon method (Palmer et al, 1999;Yu and Palmer, 2001). The Capon method is a self-adaptive signal processing.…”

Section: Introductionmentioning

confidence: 99%

“…The Capon method is a convenient, efficient, and robust procedure for processing the multi-frequency radar data (Yu and Palmer, 2001). Nevertheless, this method is subject to a limitation in spectral analysis.…”

Section: Introductionmentioning

confidence: 99%

High-range resolution spectral analysis of precipitation through range imaging of the Chung-Li VHF radar

et al. 2018

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Abstract. Multi-frequency range imaging (RIM) has been operated in the Chung-Li very high-frequency (VHF) radar, located on the campus of National Central University, Taiwan, since 2008. RIM processes the echo signals with a group of closely spaced transmitting frequencies through appropriate inversion methods to obtain high-resolution distribution of echo power in the range direction. This is beneficial to the investigation of the small-scale structure embedded in dynamic atmosphere. Five transmitting frequencies were employed in the radar experiment for observation of the precipitating atmosphere during the period between 21 and 23 August 2013. Using the Capon and Fourier methods, the radar echoes were synthesized to retrieve the temporal signals at a smaller range step than the original range resolution defined by the pulse width, and such retrieved temporal signals were then processed in the Doppler frequency domain to identify the atmosphere and precipitation echoes. An analysis called conditional averaging was further executed for echo power, Doppler velocity, and spectral width to verify the potential capabilities of the retrieval processing in resolving small-scale precipitation and atmosphere structures. Pointby-point correction of range delay combined with compensation of range-weighting function effect has been performed during the retrieval of temporal signals to improve the continuity of power spectra at gate boundaries, making the smallscale structures in the power spectra more natural and reasonable. We examined stratiform and convective precipitation and demonstrated their different structured characteristics by means of the Capon-processed results. The new element in this study is the implementation of RIM on spectral analysis, especially for precipitation echoes.

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Atmospheric radar imaging using multiple‐receiver and multiple‐frequency techniques

Cited by 41 publications

References 28 publications

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Evaluation of multifrequency range imaging technique implemented on the Chung–Li VHF atmospheric radar

High-range resolution spectral analysis of precipitation through range imaging of the Chung-Li VHF radar

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