• Title/Summary/Keyword: Initial distortion

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Simulation of the Ocean Circulation Around Ulleungdo and Dokdo Using a Numerical Model of High-Resolution Nested Grid (초고해상도 둥지격자 수치모델을 이용한 울릉도-독도 해역 해양순환 모의)

  • Kim, Daehyuk;Shin, Hong-Ryeol;Choi, Min-bum;Choi, Young-Jin;Choi, Byoung-Ju;Seo, Gwang-Ho;Kwon, Seok-Jae;Kang, Boonsoon
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.32 no.6
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    • pp.587-601
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    • 2020
  • The ocean circulation was simulated in the East Sea and Ulleungdo-Dokdo region using ROMS (Regional Ocean Modeling System) model. By adopting the East Sea 3 km model and the HYCOM 9 km data, Ulleungdo 1 km model and Ulleungdo-Dokdo 300 m model were constructed with one-way grid nesting method. During the model development, a correction method was proposed for the distortion of the open boundary data which may be caused by the bathymetry data difference between the mother and child models and the interpolation/extrapolation method. Using this model, a super-high resolution ocean circulation with a horizontal resolution of 300 m near the Ulleungdo and Dokdo region was simulated for year 2018. In spite of applying the same conditions except for the initial and boundary data, the numerical models result indicated significantly different characteristics in the study area. Therefore, these results were compared and verified by using the surface current data estimated by satellites altimeter data and temperature data from NIFS (National Institute of Fisheries Science). They suggest that in general, the improvement of the one-way grid nesting with the HYCOM data on RMSE, Mean Bias, Pattern correlation and Vector correlation is greater in 300 m model than in the 1 km model. However, the nesting results of using East Sea 3 km model showed that simulations of the 1 km model were better than 300 m model. The models better resolved distinct ridge/trough structures of isotherms in the vertical sections of water temperature when using the higher horizontal resolution. Furthermore, Karman vortex street was simulated in Ulleungdo-Dokdo 300 m model due to the terrain effect of th islands that was not shown in the Ulleungdo 1 km model.