Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
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Quantitative precipitation estimation of X-band radar using empirical relationship

경험적 관계식을 이용한 X밴드 레이더의 정량적 강우 추정

  • Song, Jae In (Department of Future & Smart Construction Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Lim, Sanghun (Department of Future & Smart Construction Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Cho, Yo Han (Han River Flood Control Office) ;
  • Jeong, Hyeon Gyo (Han River Flood Control Office)
  • 송재인 (한국건설기술연구원 미래스마트건설연구본부) ;
  • 임상훈 (한국건설기술연구원 미래스마트건설연구본부) ;
  • 조요한 (한강홍수통제소) ;
  • 정현교 (한강홍수통제소)
  • Received : 2022.05.11
  • Accepted : 2022.09.01
  • Published : 2022.09.30
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Abstract

As the occurrences of flash floods have increased due to climate change, faster and more accurate precipitation observation using X-band radar has become important. Therefore, the Ministry of Environment installed two dual-pol X-band radars at Samcheok and Uljin. The radar data used in this study were obtained from two different elevation angles and composed to reduce the shielding effect. To obtain quantitative rainfall, quality control (QC), KDP retrieval, and Hybrid Surface Rainfall (HSR) methods were sequentially applied. To improve the accuracy of the quantitative precipitation estimation (QPE) of the X-band radar, we retrieved parameters for the relationship between rainfall rate and specific differential phase, which is commonly called the R-KDP relationship; hence, an empirical approach was developed using multiple rain gauges for those two radars. The newly suggested relationship, R = 27.4K0.81DP, slightly increased the correlation coefficient by 1% more than the relationship suggested by the previous study. The root mean square error significantly decreased from 3.88 mm/hr to 3.68 mm/hr, and the bias of the estimated precipitation also decreased from -1.72 mm/hr to -0.92 mm/hr for overall cases, showing the improvement of the new method.

기후변화로 인한 돌발홍수의 발생 빈도 증가에 따라 X밴드 레이더를 이용한 보다 빠르고 정확한 강수 관측이 중요해지고 있다. 이에 환경부는 삼척과 울진에 2기의 이중편파 X밴드 레이더를 설치했다. 본 연구에서는 차폐 효과를 최소화하기 위해 설치된 2기의 각 레이더에서 2개의 고도각 관측을 수행한 뒤 얻어진 관측자료를 합성하여 정량강우를 산정하였다. 정량강우산정을 위해서 먼저 품질관리(QC) 기법을 적용한 뒤 비차등위상차(KDP)를 산출하고 하이브리드 고도면 강수추정(HSR) 기법을 적용하였다. 본 연구에서는 산출된 KDP를 이용해 R-KDP 관계로 불리는 강우강도와 비차등위상차의 관계식을 적용하여 얻어지는 정량적 강우추정(QPE)의 정확도 상승을 위해 해당 관계식의 매개변수를 추정했다. 매개변수 추정을 위해서 여러 개의 강우량계와 레이더 자료를 바탕으로 경험적 방법을 개발하였다. 새로 제안된 매개변수를 이용한 관계식(R = 27.4K0.81DP)은 관측된 강수량에 대해 추정된 강수의 상관계수를 선행연구대비 1% 정도 약간 상승시켰다. 마찬가지로, 제곱평균 제곱근오차는 3.88 mm/hr에서 3.68 mm/hr로 감소했고 편차는 -1.72에서 -0.92로 상관계수보다 유의미하게 감소해 정확도가 상승했음을 보였다.

Keywords

Acknowledgement

본 연구는 K-water 수탁과제인 부산 에코델타 스마트시티 소형 강우관측장비 강우추정 기술개발 연구용역의 지원을 받아 수행되었습니다.

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