Attenuation Correction of Weather Radar Reflectivity with Arbitrary Oriented Microwave Link

Zhang, Peng; Liu, Xichuan; Li, Zhaoming; Zhou, Zeming; Song, Kun; Yang, Pinglv

doi:10.1155/2017/6124149

Cited by 33 publications

(17 citation statements)

References 25 publications

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“…Therefore, for precise discharge simulations by means of HMs, dense meteorological station networks are necessary, which is often impossible in tropical mountain catchments, which is why meteorological radar has an advantage. Despite the high installation and operation cost of sophisticated radar systems (C-Band or S-Band; e.g., [102,103]), recently, cost-effective X-band technologies have become available (e.g., [29,104]), which are also affordable for developing countries. The advantages of meteorological radars over point measurements (rain gauges) are that these systems detect the precipitation over larger areas in high spatiotemporal resolution, and for radar data calibration only isolated ground information at strategic points is required [22,30].…”

Section: Discussionmentioning

confidence: 99%

River Discharge Simulation in the High Andes of Southern Ecuador Using High-Resolution Radar Observations and Meteorological Station Data

et al. 2019

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The prediction of river discharge using hydrological models (HMs) is of utmost importance, especially in basins that provide drinking water or serve as recreation areas, to mitigate damage to civil structures and to prevent the loss of human lives. Therefore, different HMs must be tested to determine their accuracy and usefulness as early warning tools, especially for extreme precipitation events. This study simulated the river discharge in an Andean watershed, for which the distributed HM Runoff Prediction Model (RPM) and the semi-distributed HM Hydrologic Modelling System (HEC-HMS) were applied. As precipitation input data for the RPM model, high-resolution radar observations were used, whereas the HEC-HMS model used the available meteorological station data. The obtained simulations were compared to measured discharges at the outlet of the watershed. The results highlighted the advantages of distributed HM (RPM) in combination with high-resolution radar images, which estimated accurately the discharges in magnitude and time. The statistical analysis showed good to very good accordance between observed and simulated discharge for the RPM model (R2: 0.85–0.92; NSE: 0.77–0.82), whereas for the HEC-HMS model accuracies were lower (R2: 0.68–0.86; NSE: 0.26–0.78). This was not only due to the application of means values for the watershed (HEC-HMS), but also to limited rain gauge information. Generally, station network density in tropical mountain regions is poor, for which reason the high spatiotemporal precipitation variability cannot be detected. For hydrological simulation and forecasting flash floods, as well as for environmental investigations and water resource management, meteorological radars are the better choice. The greater availability of cost-effective systems at the present time also reduces implementation and maintenance costs of dense meteorological station networks.

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Section: Discussionmentioning

confidence: 99%

River Discharge Simulation in the High Andes of Southern Ecuador Using High-Resolution Radar Observations and Meteorological Station Data

et al. 2019

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“…In this respect, Bringi et al [7] proposed a self-consistent method that did not set the coefficient α as a fixed value. Furthermore, instead of using a fixed α in the DPRm, which is based on a dual-polarization radar, the method proposed by Zhang et al [13] estimated the optimal α using an iterative process based on a dual-polarimetric radar measurement with a single microwave link (RSML). In contrast to the weather radar, where there is a factor of 1 × 10 −17 between the received and transmitted signal power level (which is caused by a small backscatter proportion), the amplitude of the link can be directly measured [26].…”

Section: Attenuation Correction Using Dual-polarimetric Radarmentioning

confidence: 99%

“…However, the microwave link used in these methods must be situated along the radial direction of the radar, which restrains the applications of microwave links for correcting radar attenuation. Furthermore, Zhang et al [13] presented a new method based on the DPRm for correcting the attenuation of radar reflectivity using a dual-polarimetric radar and an arbitrary-oriented microwave link. This method can be used to broaden the application scope of microwave links in the attenuation correction of radar reflectivity.…”

Section: Introductionmentioning

confidence: 99%

“…It is critical to optimize the correction coefficients a and α to improve the effectiveness of radar attenuation correction methods, because these coefficients vary widely with respect to the drop size distribution and drop temperature. Thus, we propose the use of a modified method that employs seven microwave links to primarily estimate the optimal correction coefficient, a, when an attenuation reference cannot be provided by one of the microwave links because of heavy rainfall [13]. This method effectively reduces any instability problems that have been reported in previous methods as it uses multiple adjacent microwave links.…”

Section: Introductionmentioning

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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“…Microwave links, through which very high temporal resolution data can be observed and compared with rain gauge data, are useful for estimating accurate near-surface rainfall rates in urban areas [19,20] and can also be used to estimate variations in drop size distribution (DSD) [21]. The path-averaged rainfall rate also provides new rainfall information for ground adjustment of weather radar rainfall estimates [22]. A microwave link can be thought of as a range of profiles of DSDs through which an electromagnetic wave propagates [8].…”

Section: Introductionmentioning

confidence: 99%

Rainfall Detection and Rainfall Rate Estimation Using Microwave Attenuation

Kim

Kwon

2018

Atmosphere

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Eight microwave links operating at frequencies ranging from 6 to 8 GHz and with path lengths ranging from 5.7 to 37.4 km traversing the city of Seoul, Korea are used to detect rainfall and estimate path-averaged rainfall rates. Rainfall detection using rain-induced attenuation (dB) was validated by rain detectors installed at automatic weather stations, and the results confirmed that microwave links can be used to detect rainfall with an accuracy ≥80%. The power-law R-k relationships between rain-induced specific attenuation, k (dB km −1 ), and the rainfall rate, R (mm h −1 ), were established and cross-validated by estimating the path-averaged rainfall rate. The mean bias of the path-averaged rainfall rate, as compared to the rainfall rate from ground rain gauges, was between −3 and 1 mm h −1 . The improved accuracy of rainfall detection led to the improved accuracy of the path-averaged rainfall rate. Hence, it was confirmed that microwave links, used for broadcasting and media communications, can identify rainy or dry periods (rain spells or dry spells) in a way comparable to rain detectors and provide high time-resolution rainfall rates in real time.

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Attenuation Correction of Weather Radar Reflectivity with Arbitrary Oriented Microwave Link

Cited by 33 publications

References 25 publications

River Discharge Simulation in the High Andes of Southern Ecuador Using High-Resolution Radar Observations and Meteorological Station Data

River Discharge Simulation in the High Andes of Southern Ecuador Using High-Resolution Radar Observations and Meteorological Station Data

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

Rainfall Detection and Rainfall Rate Estimation Using Microwave Attenuation

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