A discussion on the variations of MST/ST radar echo power with an atmospheric layer resolved by frequency domain interferometry technique

Chen, J. S.; Chu, Yen Hsyang

doi:10.1029/1999rs002238

Cited by 2 publications

(3 citation statements)

References 19 publications

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“…Similar method was also employed by Brown and Fraser [1996] and Luce et al [2001] in their multiple–frequency observations. However, Chen and Chu [2000] suggested that the relationship between echo power and FDI layer position can also be applied to reveal the FDI phase bias under the situation of single layer in the radar volume. In addition, Palmer et al [2001] and Chilson et al [2001] considered the initial phases of the carrier frequencies and measured them from the signals that were leaked from the transmitted signals back to the receiver by an ultrasonic delay line.…”

Section: Introductionmentioning

confidence: 99%

“…We indeed found systematic bias in the FDI phase. Moreover, phase calibration using the condition of a single layer in the radar volume, which was implemented by Chen and Chu [2000], is one application of echo power. We will demonstrate that the condition of single layer can be released in using the relationship between echo power and FDI phase.…”

Section: Introductionmentioning

confidence: 99%

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On the phase biases of multiple‐frequency radar returns of mesosphere‐stratosphere‐troposphere radar

Chen

2004

Radio Science

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[1] The frequency domain interferometry (FDI) technique uses two or more frequencies to measure the positions and thicknesses of the atmospheric thin layers embedded in the radar volume, in which the cross-correlation analyses of the radar echoes for the pairs of carrier frequencies are performed and the resultant amplitudes and phases (FDI phase) are both employed. However, in light of the possibility that the characteristics of radar system, mean refractivity gradient, and other factors that would significantly affect the FDI phase, calibration of the FDI phase is required to improve the measurement. In this study we employed three methods in measuring the phase bias in the FDI observation using the Chung-Li VHF radar; namely, (1) histogram of the FDI phases, (2) relationship between echo power and FDI phase, and (3) the FDI phase of aircraft. Both methods 1 and 2 are based on the range weighting effect on the radar echoes returned from the atmospheric scatterers; however, the first produced smaller FDI phase bias than the second. To examine such discrepancy in the results of methods 1 and 2, method 3 was exploited and provided more consistent values of phase biases with those of method 2. Considering that the radar echoes reflected from aircrafts are not related to uncertain conditions of the atmosphere such as mean reflectivity gradients and statistical characteristics, the results of methods 2 and 3 may be more reliable. Besides, the first two methods demonstrated that the FDI phase bias was quasi-linearly dependent on the separation of frequency pair, which not only consolidates the existence of the FDI phase bias but also indicates that a systematic phase compensation for the FDI analysis is possible. For example, considering 0.1-, 0.4-, and 0.8-ms time delays of signals for the returns of 1-, 2-, and 4-ms pulse lengths, respectively, the FDI phase biases can be removed effectively. Same methods and procedures can be applied to other radar systems.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the phase biases of multiple‐frequency radar returns of mesosphere‐stratosphere‐troposphere radar

Chen

2004

Radio Science

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“…Three co-located atmospheric radars on the campus of National Central University (24.97 • N, 121.18 • E) were employed in the campaign experiment for the wind velocity measurements and comparisons, i.e., 52 MHz Chung-Li VHF radar, 449 MHz wind profiler, and 1290 MHz wind profiler. The Chung-Li VHF radar is a teaching and research facility that can not only measure atmospheric wind velocity, turbulence, precipitation, lightning, meteor trail, and wave phenomena in the troposphere and/or mesosphere, but also can detect the echoes from ionospheric field-aligned irregularities at Bragg scale to study the plasma irregularities and ionospheric dynamics in the E and F regions [32][33][34][35][36]. The Chung-Li VHF radar is equipped with three phased-array antennas with a total area of 0.9 hectares; they are a strato-and troposphere (ST) array, ionospheric array, and interferometry array.…”

Section: Experimental Setup and Data Analysismentioning

confidence: 99%

Intercomparisons of Tropospheric Wind Velocities Measured by Multi-Frequency Wind Profilers and Rawinsonde

Chen

Chu

2021

Atmosphere

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Concurrent measurements of three-dimensional wind velocities made with three co-located wind profilers operated at frequencies of 52 MHz, 449 MHz, and 1.29 GHz for the period 12–16 September 2017 are compared for the first time in this study. The velocity–azimuth display (VAD) method is employed to estimate the wind velocities. The result shows that, in the absence of precipitation, the root mean square difference (RMSD) in the horizontal wind speed velocities U and wind directions D between different pairs of wind profilers are, respectively, in the range of 0.94–0.99 ms−1 and 7.7–8.3°, and those of zonal wind component u and meridional wind component v are in the respective ranges of 0.91–1.02 ms−1 and 1.1–1.24 ms−1. However, the RMSDs between wind profilers and rawinsonde are in the range of 2.89–3.26 ms−1 for horizontal wind speed velocity and 11.17–14.48° for the wind direction, which are around 2–3 factors greater than those between the wind profilers on average. In addition to the RMSDs, MDs between wind profilers and radiosonde are around one order of magnitude larger than those between wind profilers. These results show that the RMSDs, MDs, and Stdds between radars are highly consistent with each other, and they are much smaller than those between radar and rawinsonde. This therefore suggests that the wind profiler-measured horizontal wind velocities are much more reliable, precise, and accurate than the rawinsonde measurement.

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A discussion on the variations of MST/ST radar echo power with an atmospheric layer resolved by frequency domain interferometry technique

Cited by 2 publications

References 19 publications

On the phase biases of multiple‐frequency radar returns of mesosphere‐stratosphere‐troposphere radar

On the phase biases of multiple‐frequency radar returns of mesosphere‐stratosphere‐troposphere radar

Intercomparisons of Tropospheric Wind Velocities Measured by Multi-Frequency Wind Profilers and Rawinsonde

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