Ocean and Polar Research

Vol. 42(3):179–194

KCI

[논문]자료동화 기법에 따른 황·동중국해 지역 해양순환모델 결과 비교

이준호

문재홍

최영진

The present study aims to evaluate the effects of satellite-based SST (OSTIA) assimilation on a
regional ocean circulation model for the Yellow and East China Seas (YECS), using three different
assimilation methods: the Ensemble Optimal Interpolation (EnOI), Ensemble Kalman Filter (EnKF), and
4-Dimensional Variational (4DVAR) techniques, which are widely used in the ocean modeling communities.
The model experiments show that an improved initial condition by assimilating the SST affects the seasonal
water temperature and water mass distributions of the YECS. In particular, the SST data assimilation
influences the temperature structures horizontally and vertically in winter, thereby improving the behavior of
the YS warm current water. This is due to the fact that during wintertime the water column is well mixed, which
is directly updated by the SST assimilation. The model comparisons indicate that the SST assimilation can
improve the model performance in resolving the subsurface structures in wintertime, but has a relatively small
impact in summertime due to the strong stratification. The differences among the different assimilation
experiments are obvious when the SST was sharply changed due to a typhoon passage. Overall, the EnKF and
4DVAR show better agreement with the observations than the EnOI. The relatively low performance of EnOI
under storm conditions may be related with a limitation of EnOI method whereby an analysis is obtained from
a number of climatological fields, and thus the typhoon-induced SST changes in short-time scales may not be
adequately reflected in the data assimilation.

2020-08-29

http://dx.doi.org/10.4217/OPR.2020.42.3.179