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A study on propagation of uncertainties for a mixing ratio calculation by seawater intrusion

해수침투 발생 시 혼합비 계산의 오차에 관한 연구

  • 이정훈 (이화여자대학교 과학교육과)
  • Received : 2018.08.27
  • Accepted : 2018.09.19
  • Published : 2018.10.31

Abstract

It is crucial to determine a mixing ratio using an end-member mixing analysis when there is seawater intrusion. In this study, an error from the calculation of the mixing ratio between seawater and freshwater based on the principles of uncertainty was determined. I present the errors in the calculated mixing ratios as a function of the chemical difference between the mean seawater concentrations and standard deviations. The error is caused by: (1) the mixing ratio between seawater and freshwater; (2) the difference between the mean concentration and the standard deviation; and (3) the difference of the tracer concentration between freshwater and seawater (inversely). In particular, the error may determine hydrogeochemical process (either precipitation or dissolution) when a value of ionic delta (difference between measured and theoretical concentration) is close to zero during cation exchange by seawater intrusion.

해수침투가 발생할 때 혼합비를 결정하는 것은 해수침투연구에 매우 중요한 사항이며, 단성분 혼합분석방법을 주로 사용한다. 본 연구에서는 이러한 해수와 담수의 혼합비 계산시 발생되는 오차를 불확정성의 원리를 이용하여 결정하였다. 또한 해수침투 혼합비를 계산할 때 평균값과 표준편차의 차이에 의해 발생할 수 있는 혼합비의 오차를 제시하였다. 이러한 오차의 크기는 (1) 혼합비가 커질수록, (2) 사용된 평균값과 표준편차값의 차이가 클수록, 마지막으로 (3) 해수와 배경지하수의 추적자 농도 값이 작을수록 커진다. 특히, 해수침투가 발생하여 양이온교환반응이 일어날 때 이온델타(이론적인 지하수화학성분과 실제 시료의 화학성분의 차이)값이 0 근처에서는 오차값이 지구화학적인 상태(침전 또는 용해)를 결정하는 데에 기여할 수 있다.

Keywords

Acknowledgement

Grant : 장보고기지 주변 빙하 하부 수문계측망 특성 규명

Supported by : 극지연구소

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