Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
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Theoretical analysis of quantification of drought frequency inflow series via K-water cumulative difference method

누가차분법을 통한 가뭄 빈도유입량 산정에 관한 이론적 고찰

  • Kim, Jiheun (International School of Urban Sciences, University of Seoul) ;
  • Lee, Jae Hwang (Department of Civil & Environmental Eng., Seoul National University) ;
  • Kim, Young-Oh (Department of Civil & Environmental Eng., Seoul National University)
  • 김지흔 (서울시립대학교 도시과학연구원 국제도시 및 인프라연구센터) ;
  • 이재황 (서울대학교 공과대학 건설환경공학부) ;
  • 김영오 (서울대학교 공과대학 건설환경공학부)
  • Received : 2022.08.24
  • Accepted : 2022.08.31
  • Published : 2022.09.30
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Abstract

Reliable drought inflow scenarios are required to plan reservoirs in response to the present severe drought-like conditions. However, the previously developed method for generating drought inflows, the K-water cumulative difference method (KCM), is considered inadequate owing to its potential for negative inflow, reversal phenomena, and overestimation. Nevertheless, the occurrence of these aspects has not been theoretically analyzed. Hence, this study employed the quantile function and frequency factor for log-normal and Gumbel distributions to quantify the contributing factors of these limitations. Consequently, it was found that the negative inflows are generated when the difference in the location parameters, during the accumulation process, exceeds that of the scale parameters. In addition, as the standard deviation decrease during the accumulation process, the reversal phenomena, and inflated values prevailed.

이상기후로 가뭄이 빈번해짐에 따라 수자원 시설의 가뭄대응력 산정에 대한 필요성이 커지고 있다. 이를 위해서는 신뢰할 수 있는 갈수빈도 유입량 추정 연구가 선행되어야 한다. 본 연구는 기존 K-water의 가뭄 빈도유입량 추정방법인 누가차분법의 세 가지 한계, 즉 음의 값과 역전현상, 그리고 평년 이상으로 과대 산정되는 문제의 발생조건에 대해 각각 2변수 log-normal 분포와 Gumbel 분포를 적용하여 이론적 고찰을 실시하였다. 그 결과, 음의 값은 누가 과정에서 scale parameter보다 location parameter의 변화가 커지는 경우 발생함을 확인하였고, 역전현상 및 평년보다 큰 가뭄유입량은 누가 과정에서 표준편차가 감소하는 경우 발생하는 것으로 분석되었다.

Keywords

Acknowledgement

이 연구는 K-water와 한국연구재단의 BK21 PLUS 사업의 지원으로 수행되었습니다.

References

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