Improving S-Band Polarimetric Radar Monsoon Rainfall Estimation with Two-Dimensional Video Disdrometer Observations in South China

Guo, Zhongyang; Hu, Sheng; Liu, Xiantong; Chen, Xingdeng; Honghao, Zhang; Qi, Tao; Guang-yu, Zeng

doi:10.3390/atmos12070831

Cited by 7 publications

(8 citation statements)

References 29 publications

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“…It is important to evaluate the performance of various DSD-based dual-polarization radar QPE relations in QPE applications. R calculated from DSD (Equation ( 4)) was used to evaluate the QPE relations [27,28,53,54,69]. In this study, three evaluation indicatorsthe correlation coefficient (CC), root mean square error (RMSE), and normalized mean absolute error (NMAE)-were used to evaluate the different QPE relations for different bands [27,53].…”

Section: Dual-polarization Radar Qpe Relationsmentioning

confidence: 99%

“…R classes have an important impact on the performance of dual-polarization radar QPE estimators [53,55,69] as well as radar bands [53,55,69]. To quantify the performance of QPE estimators under different R classes and different radar bands, we used CC, RMSE, and NMAE to evaluate the performance of these QPE estimators in detail.…”

Section: Qpe Relations Under Different Rain Rate Classesmentioning

confidence: 99%

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Microphysical Characteristics of Raindrop Size Distribution and Implications for Dual-Polarization Radar Quantitative Precipitation Estimations in the Tianshan Mountains, China

Zeng

Yang

et al. 2023

Remote Sensing

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In order to improve the understanding of the microphysical characteristics of raindrop size distribution (DSD) under different rainfall rates (R) classes, and broaden the knowledge of the impact of radar wavelengths and R classes on the QPE of dual-polarization radars in the Tianshan Mountains, a typical arid area in China, we investigated the microphysical characteristics of DSD across R classes and dual-polarimetric radar QPE relationships across radar wavelengths and R classes, based on the DSD data from a PARSIVEL2 disdrometer at Zhaosu in the Tianshan Mountains during the summers of 2020 and 2021. As the R class increased, the DSD became wider and flatter. The mean value of the mass-weighted mean diameters (Dm) increased, while the mean value of logarithm normalized intercept parameters (log10 Nw) decreased after increasing from C1 to C3, as the R class increased. The largest contributions to R and the radar reflectivity factor from large raindrops (diameter > 3 mm) accounted for approximately 50% and 97%, respectively, while 84% of the total raindrops were small raindrops (diameter < 1 mm). Dual-polarization radars—horizontal polarization reflectivity (Zh), differential reflectivity (Zdr), and specific differential phase (Kdp)—were retrieved based on the DSD data using the T-matrix scattering method. The DSD-based polarimetric radar QPE relations of a single-parameter (R(Zh), R(Kdp)), and double-parameters (R(Zh,Zdr), R(Kdp,Zdr)) on the S-, C-, and X-bands were derived and evaluated. Overall, the performance of the R(Kdp) (R(Kdp,Zdr)) scheme was better than that of R(Zh) (R(Zh,Zdr)) for the QPE in the three bands. Furthermore, we have for the first time confirmed and quantified the performance differences in the QPE relationship of dual-polarization radars under different schemes, radar wavelengths, and R classes in typical arid areas of China. Therefore, selecting an appropriate dual-polarization radar band and QPE scheme for different R classes is necessary to improve the QPE ability compared with an independent scheme under all R classes.

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Section: Dual-polarization Radar Qpe Relationsmentioning

confidence: 99%

Section: Qpe Relations Under Different Rain Rate Classesmentioning

confidence: 99%

Microphysical Characteristics of Raindrop Size Distribution and Implications for Dual-Polarization Radar Quantitative Precipitation Estimations in the Tianshan Mountains, China

Zeng

Yang

et al. 2023

Remote Sensing

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“…To evaluate the effectiveness of the QPE algorithm, the estimated hourly rainfall and observed hourly rainfall data were compared. The normalized error (NE), root mean square error (RMSE) and CC between the two were calculated [39], as follow Equations ( 1)-( 3). NE represents the deviation between the estimated value and the measured value; the smaller the value, the higher the accuracy and credibility of precipitation estimation.…”

Section: Qpe Algorithm Evaluationmentioning

confidence: 99%

“…They highlighted the importance of constructing localized QPE algorithms. In 2021, based on a constraint model obtained using raindrop size inversion [38], Guo et al [39] established a QPE scheme (2DVD-SCM) for the South China monsoon using two-dimensional video disdrometers (2DVDs) and polarimetric radars located in South China. This algorithm achieves significantly higher estimation accuracy than the classic CSU-HIDRO algorithm in most monsoon-induced rainfall events, improving the QPE accuracy for South China monsoon-induced precipitation.…”

Section: Introductionmentioning

confidence: 99%

An Improved S-Band Polarimetric Radar-Based QPE Algorithm for Typhoons over South China Using 2DVD Observations

Guo

Guang-yu

et al. 2023

Atmosphere

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Polarimetric radar data are an important tool for quantitative precipitation estimation (QPE), which is essential for monitoring and forecasting precipitation. Previous studies have shown that the drop size distribution (DSD) and polarimetric radar parameters of typhoon-induced precipitation differ significantly from those of other types of rainfall. South China is a region that frequently experiences typhoons and heavy rainfall, which can cause serious disasters. Therefore, it is critical to develop a QPE algorithm that is suitable for typhoon precipitation over South China. In this study, we constructed four simple QPE estimators, R(ZH), R(ZH, ZDR), R(KDP) and R(KDP, ZDR) based on two-dimensional video disdrometer (2DVD) DSD observations of typhoon-induced precipitation over South China in 2017–2018. We analyzed the DSD characteristics and the estimation accuracy of these four QPE estimators in the reflectivity–differential reflectivity (ZH–ZDR) space, as well as the S-band polarimetric radar (S-POL) data of seven typhoon-induced precipitation events that affected South China in 2017–2019. We used these data to quantitatively determine the optimal ranges of the estimators and establish a typhoon precipitation QPE algorithm for typhoon-induced precipitation over South China (2DVD-Typhoon). The evaluation results showed that: (1) compared to R(ZH) and R(KDP), R(ZH, ZDR) and R(KDP, ZDR) had lower performance in estimating typhoon-induced rainfall after incorporating the polarimetric parameter ZDR, as strong crosswind of the typhoon caused some bias in the raindrop-induced ZDR; (2) the 2DVD-Typhoon algorithm utilizes the respective advantages of the individual estimators to generate the best QPE results; (3) the QPE performance of 2DVD-Typhoon and the Colorado State University–Hydrometeor Identification Rainfall Optimization (CSU-HIDRO) is used as a comparison for hourly rainfall, cumulative rainfall and different rainfall intensity. The comparison shows that 2DVD-Typhoon gives a better normalized error (NE), root mean square error (RMSE) and correlation coefficient (CC), indicating its strength in rainfall estimation for typhoons over South China. The above results provide theoretical support for improving typhoon-induced rainfall monitoring and numerical weather forecasting models in South China.

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“…The YJ S-POL is located about 10 km from the coastline and 105.7 m above sea level. It was upgraded from the China New Generation Weather Radar/SA (CINRAD/SA) to polarimetric radar in March 2016 [46]. The YJ S-POL operates with the volume coverage pattern 21 (VCP-21) scanning mode, consisting of single-elevation plan position indicator (PPI) scans between 0.5 • and 19.5 • with a 0.95 • beam width and a 0.25 km radial resolution.…”

Section: Data and Instrumentsmentioning

confidence: 99%

Multiscale Perspectives on an Extreme Warm-Sector Rainfall Event over Coastal South China

Luo

et al. 2022

Remote Sensing

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On 22 June 2017, an extreme warm-sector rainfall event hit the western coastal area of South China, with maximum hourly and 12-h rainfall accumulations of 189.4 and 464.8 mm, respectively, which broke local historical records. Multisource observations were used to reveal multiscale processes contributing to the extreme rainfall. The results showed that a marine boundary layer jet (BLJ) coupled with a synoptic low-level jet (LLJ) inland played an important role in the formation of an extremely humid environment with a very low lifting condensation level of near-surface air. Under the favorable pre-convective conditions, convection was initialized at a mesoscale convergence line, aided by topographic lifting in the evening. During the nocturnal hours, the rainstorm developed and was maintained by a quasi-stationary mesoscale outflow boundary, which continuously lifted warm, moist air transported by the enhanced BLJ. When producing the extreme rainfall rates, the storm possessed relatively weak convection, with the 40 dBZ echo top hardly reaching 6 km. The extreme rainfall was produced mainly by the warm rain microphysical processes, mainly because the humid environment and the deep warm cloud layer facilitated the clouds’ condensational growth and collision–coalescence, and also reduced rain evaporation. As the storm evolved, the raindrop concentration increased rapidly from its initial stage and remained high until its weakening stage, but the mean raindrop size changed little. The extreme rain was characterized by the highest concentration of raindrops during the storm’s lifetime with a mean size of raindrops slightly larger than the maritime regime.

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Improving S-Band Polarimetric Radar Monsoon Rainfall Estimation with Two-Dimensional Video Disdrometer Observations in South China

Cited by 7 publications

References 29 publications

Microphysical Characteristics of Raindrop Size Distribution and Implications for Dual-Polarization Radar Quantitative Precipitation Estimations in the Tianshan Mountains, China

Microphysical Characteristics of Raindrop Size Distribution and Implications for Dual-Polarization Radar Quantitative Precipitation Estimations in the Tianshan Mountains, China

An Improved S-Band Polarimetric Radar-Based QPE Algorithm for Typhoons over South China Using 2DVD Observations

Multiscale Perspectives on an Extreme Warm-Sector Rainfall Event over Coastal South China

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