Attenuation Correction Effects in Rainfall Estimation at X-Band Dual-Polarization Radar: Evaluation with a Dense Rain Gauge Network

Oh, Young-a; Lee, Daehyung; Jung, Sung-Hwa; Nam, Kyung-Yeub; Lee, GyuWon

doi:10.1155/2016/9716535

Cited by 6 publications

(6 citation statements)

References 22 publications

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“…A stratiform rainfall event that occurred from 19:21 LST on 2 May 2016 to 08:50 LST on 3 May 2016, was also analyzed to further assess the performance of the attenuation correction methods. The CTH was approximately 5 km (Figure 2e) in the study area and the RI was less 10 mm h −1 (Figure 3d); these results were consistent with the classification schemes [32], and the CT (Figure 3f) was "low cloud. "…”

Section: Reflectivity Of Convective and Stratiform Rainfallsupporting

confidence: 80%

“…Classification schemes using ground-based weather radar can identify [30] areas associated with the bright band [31]. Simple classification schemes (those that provide a threshold for radar reflectivity and the rainfall rate) are used to separate convective rainfall (≥40 dBZ or ≥10 mm h −1 ) from stratiform rainfall (<40 dBZ or <10 mm h −1 ) [32], where convective rainfall cases show rapid spatial and temporal variations with spatial heterogeneity. COMS data are also used to compare convective rainfall and stratiform rainfall.…”

Section: Reflectivity Of Convective and Stratiform Rainfallmentioning

confidence: 99%

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Attenuation Correction of X-Band Radar Reflectivity Using Adjacent Multiple Microwave Links

Kim

Kwon

2020

Remote Sensing

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Rain attenuation can hinder the implementation of quantitative precipitation estimations using X-band weather radar. Numerous studies have been conducted on correcting the attenuation of radar reflectivity by utilizing a dual-polarimetric radar and an arbitrary-oriented microwave link; however, there is a need to optimize the required number of microwave links and their locations. In this study, we tested four attenuation correction methods and proposed a novel algorithm based on the sole use of adjacent multiple microwave links. The attenuation of the X-band radar reflectivity was corrected by performing forward iterations at each link, and the correction coefficients were statistically analyzed to reduce the instability problem. The algorithms of each method were evaluated by studying the cases of convective and stratiform rainfall, and then validated by comparing the corrected reflectivity of the X-band radar with the qualitatively controlled reflectivity of the S-band radar. The new method was as efficient as the conventional method based on the specific differential phase of dual-polarimetric radar. Furthermore, the correction coefficient was more effectively optimized and stabilized using seven microwave links rather than a single link, and no further independent reference data were required. In addition, the attenuation correction also accounted for spatiotemporal differentiation depending on the rainfall type, and could recover the physical structure of the rainfall. The method developed herein can facilitate estimations of quantitative rainfall in developing countries where dual-polarization weather radars are not common. The exploitation of microwave link data is a promising method for rainfall remote sensing.

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Section: Reflectivity Of Convective and Stratiform Rainfallsupporting

confidence: 80%

Section: Reflectivity Of Convective and Stratiform Rainfallmentioning

confidence: 99%

Attenuation Correction of X-Band Radar Reflectivity Using Adjacent Multiple Microwave Links

Kim

Kwon

2020

Remote Sensing

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“…Due to the particles inside the weather clutter, the signal is attenuated as it propagates through the clutter. For long-range propagation, the attenuation effect may be significant, especially in the X-band [18,19]. The weather clutter was highly inhomogeneous, so the attenuation was strongly dependent on the signal path inside the clutter.…”

Section: Signal Amplitude and Attenuationmentioning

confidence: 99%

Time Domain Signal Simulation of Weather Clutter for an Airborne Radar Based on Measured Data

Choi

Koh

Jung

2022

J Electromagn Eng Sci

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An airborne radar simulator for an X-band radar echo signal was implemented and numerically verified. The simulator can consider weather conditions over a large area and can use measured S-band data as input. A scheme is presented for the conversion of the S-band data to the X-band one. The amplitude and time delay due to weather particles can be theoretically calculated on the basis of reflectivity. The dynamics of the platform and clutter particles were modeled using the Doppler frequency shift in the echo signal. As the simulated weather area was very large, an efficient approximation method was designed for use in calculating the attenuation and time delay, which was also numerically verified. Finally, a scheme for extracting the reflectivity from the echo signal was formulated and was verified by comparing it with the input data.

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“…The corrections for the attenuation effects of Z and Z dr have been studied intensively, especially in relation to C-band radars [19]- [21]. The specific differential phase (K dp , • km −1 ) has been extensively used for attenuation correction for several reasons; K dp remains unaffected by attenuation and radar power calibration and is less sensitive to the natural variability of the drop size distribution (DSD) [22]. The relationship of K dp − A h and K dp − A dp is approximately linear [14], [23].…”

Section: Introductionmentioning

confidence: 99%

“…where dp is the increments of observed dp and the coefficients of α and β are in dB ( • ) −1 [11], [24]. These coefficients are sensitive to the variability of the DSD, radar wavelength, temperature, season, and precipitation type [22], [23], [25], [26]. For instance, [26] indicated that the coefficients of the A h − K dp (A dp − K dp ) relation of the X-band radar vary greatly from 0.14 to 0.34 (0.11 to 0.17) dB ( • ) −1 as a result of temperature changes and different drop deformation models.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Assessment of the Reflectivity Biases and Wet-Radome Effect Using Collocated Operational S- and C-Band Dual-Polarization Radars

Loh

Chang

Hsu

et al. 2022

IEEE Trans. Geosci. Remote Sensing

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This study assessed the long-term radar reflectivity (Z) biases of collocated S-and C-band dual-polarization radars. The systematic bias, wet-radome effect (WRE), and attenuation effect were investigated. The algorithm of self-consistency utilizes Z, differential reflectivity (Z dr ), and a specific differential phase (K dp ) to estimate the systematic bias and WRE of both radars. Eleven years of disdrometer data in northern Taiwan were used to obtain the self-consistency and K dp -based attenuation correction relation coefficients. Subsequently, a series of sensitivity tests were conducted to examine the influence of these coefficients on bias and attenuation corrections. The K dp (Z, Z dr ) relationship outperformed that of K dp (Z). The K dp (Z, Z dr ) relationship with seasonal coefficients and systematic bias-corrected Z dr constituted the optimal procedure. The corrected Z of collocated radars was in good agreement, lending further validity to the correction schemes. The results demonstrated that the stable systematic bias values of two radars were −1.89 to −1.14 dB and −2.46 to −1.87 dB. During the WRE period, additional underestimations of Z by nearly 4 and 7 dB were recorded for S-and C-band radars, respectively. The mean value of radar reflectivity near radar (Z nr ) was obtained to identify the WRE period. In this study, an innovative quadratic polynomial fitting equation was proposed to investigate the systematic and WRE biases using Z nr . Moreover, a pronounced wind intensity dependency of the WRE could be observed in the quadratic polynomial fitting equation.

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Attenuation Correction Effects in Rainfall Estimation at X-Band Dual-Polarization Radar: Evaluation with a Dense Rain Gauge Network

Cited by 6 publications

References 22 publications

Attenuation Correction of X-Band Radar Reflectivity Using Adjacent Multiple Microwave Links

Attenuation Correction of X-Band Radar Reflectivity Using Adjacent Multiple Microwave Links

Time Domain Signal Simulation of Weather Clutter for an Airborne Radar Based on Measured Data

Long-Term Assessment of the Reflectivity Biases and Wet-Radome Effect Using Collocated Operational S- and C-Band Dual-Polarization Radars

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