• Title/Summary/Keyword: Rip-current risk index

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Application of rip current likelihood distributions on rip current forecast system (이안류 예보를 위한 이안류 발생정도 분포 함수의 적용)

  • Choi, Junwoo
    • Journal of Korea Water Resources Association
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    • v.56 no.8
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    • pp.521-528
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    • 2023
  • An approach for producing a rip current risk index using the rip current likelihood distribution obtained through the FUNWAVE simulations was applied to a rip current forecast system. The approach originally developed for an observation-based real-time rip current warning system was utilized with wave forecast data instead of observations for the rip current forecast system. The availability of the present approach was checked by comparing the observation-based rip current risk index and the wave forecast-based rip current risk index of the Haeundae Beach in 2021.

A modification of the rip current warning system utilizing real-time observations: a database function of likelihood distributions (실시간 관측정보를 이용한 이안류 경보체계 개선 연구: 발생정도 DB함수의 활용)

  • Choi, Junwoo
    • Journal of Korea Water Resources Association
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    • v.55 no.10
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    • pp.843-854
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    • 2022
  • For the rip current warning system to reduce rip-current accidents, the implementation method producing the risk index was modified. To produce fast response from the warning system based on real-time observations, the method employed the numerical results (i.e., rip current likelihoods according to the possible scenario) obtained in advance. In this study, instead of using the empirical curve-fitting functions of the previous method, the present modification utilized two-dimensional distributions (i.e., wave height and period, wave height and tidal elevation, wave height and direction, wave height and spreading of frequency-directional spectrum) of rip current likelihoods stacked in a database of the system. The wave and tidal observations in 2021 at the Haeundae coast were applied to the modified system, and its performances at several real events recorded in CCTV images were presented.

Rip Current Sensitive Analysis Using Rose Diagram for Wave-Induced Current Vectors at Haeundae Beach, Korea (해빈류 벡터 장미도를 통한 해운대 해수욕장의 이안류 민감도 분석)

  • Kim, Dong Hee;Lee, Sahong;Lee, Jung Lyul
    • Journal of Ocean Engineering and Technology
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    • v.30 no.4
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    • pp.320-326
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    • 2016
  • Rip current forecasts, based on intensity, are marked in four levels—notice, watch, warning, and danger. However, numerical results are represented by current vectors, whose magnitudes are then converted into predictive levels. In the present study, the rose diagram is adapted as a determinative forecasting index and examined for the case of an ideal rip channel consisting of surface, bottom, and averaged currents. Further, it is employed in the sensitivity analysis of wave-induced currents generated by wave conditions at the Haeundae Beach. The simulation of surface onshore and bottom undertow currents is accomplished by including a mass flux term in the wave-averaged continuity equation.