Application of an empirical method to improve radar rainfall estimation using cross governmental dual-pol. radars

The primary aim of a rain radar is to observe ground-level rainfall accurately. Effective quality control of rain radar data is necessary to ensure accuracy. In the field of hydrology, various methods have been employed to improve the quality of radar rainfall by correcting or synthesizing it with gauge rainfall. However, it is more important to enhance the quality of radar polarimetric variables in order to improve the quality of radar rainfall. Rain radar systems generate various polarimetric variables through complex radar hardware systems and signal processing algorithms. Measurement errors may arise from equipment abnormalities, inappropriate operating settings, and obstructions in observation during signal processing algorithms and production process of polarimetric variables. Because rain radar is an observation device operating in real time, it entails more frequent and continuous quality control compared to flowmeters that intermittently measure streamflow. This study introduces a series of real-time quality control methods tailored for rain radar, including inspection of radar rainfall accuracy, quality analysis of polarimetric variables (ρHV, ZDR, ΦDP), error estimation of polarimetric variables, and long-term variability of errors.

unclassified

Proposal for Real-time Quality Control Method to Enhance Hydrological Application of Radar Rainfall

Yoon,

Hwang,

Kang

2023

“…. 또한 KICT 레이더는 2014년 6월에 경기도 고양시에서 발생한 직경 약 1 km의 용오름 현상을 관측하여 그 효능을 입증한 바 있다 (Jeong et al, 2016 (Ryzhkov et al, 2005;Cifelli et al, 2011;Yoon et al, 2016).…”

unclassified

Operation Techniques and Hydrological Applications of X-band Dual-polarization Radar for Monitoring Flash Flood in Metropolitan Area

Yoon¹,

Hwang²,

Lee³

et al. 2020

Self Cite

Radar is useful for monitoring flash flood in urban areas because it provides rainfall data with high spatial and temporal resolution for a wide area. In 2014, the Korea Institute of Civil Engineering and Building Technology introduced the first X-band dual-polarization radar in Korea and has subsequently been researching on flash floods in the metropolitan area using the rainfall data. Considering the various advantages of X-band dual-polarization radar, the Water Hazard Information Platform in Korea introduced two X-band dual-polarization radars (KRU and YSU radars) into the metropolitan area, in 2017. This study described the characteristics of KRU and YSU radars, their observation strategies, and quality control techniques. Moreover, we also assessed the hydrological applications of the X-band dual-polarization radars in the metropolitan area by analyzing three years of rainfall data from 2017 to 2019.

“…이에 비해 지상에 떨어진 강우의 양을 중요시하게 여겼던 국내 수문학자들은 레이더 강우를 정량 적으로 우량계 강우와 비슷하게 맞추는 통계적 방법들을 적용하였다. G/R 비를 레이더 강우에 곱하는 방법 (Yoo et al, 2013), Co-Kriging (Krajewski, 1987;Seo et al, 1990) 및 SCM (Kim et al, 2008) (Yoo et al, 2013;Yoon, Choi, et al, 2016 (Yoon, Suk, et al, 2016). 이에 Yoon, Suk, et al (2016) (Koistinen et al, 2004).…”

unclassified

“…우량계 강수량을 나타낸다. 본 연구에서는 단일편파인 반사도만을 적용하기 때문에Yoon, Suk, et al (2016)의 방법에서와 같이 반사도만을 조절해가며 레이더 강수의 정확도가 최적이 되는 레이더 반사도를 결정하였다. 이를 위해 반사도를 0 dBZ에서 20 dBZ까지 1 dBZ 간격으로 가산하였다.…”

unclassified

Quantification of Error in Reflectivity for Improving the Accuracy of the Radar Rainfall Estimated from Single Polarization Radar

Yoon¹

2018

Self Cite

There have been many limitations in the application of the hydrological field in Korea due to doubts about its accuracy, although radar-estimated rainfall has the advantage of providing high temporal and spatial resolution data. Real time ZR parameter calculation methods and many quantitative correction methods using rain gauge rainfall have been introduced to overcome the problem of accuracy. However, the accuracy of the radar rainfall after correction by these methods was a little better than before because the radar rainfall converted by the radar reflectivity had serious errors. In this study, we quantified the errors inherent in the radar reflectivity to solve the problem of accuracy of radar rainfall which has been raised in Korea over the last 10 years. The results are as follows. In the case assuming that the error variance of the radar reflectivity was 0, the bias of radar reflectivity ranged from-1 dBZ to-14 dBZ. In the case considering error variance, the bias of the radar reflectivity ranged from-3 dBZ to-15 dBZ, and the error variance ranged from 2 2 to 8 2 dBZ 2 .