Effect of the sea surface heat flux on upper layer circulation of the East/Japan Sea
- 1Kongju National University, Atmospheric science, Korea, Republic of (kobl1201@gmail.com)
- 2Kongju National University, Atmospheric science, Korea, Republic of (hrshin@kongju.ac.kr)
- 3Ocean Circulation and Climate Research Center, Korea Institute of Ocean Science & Technology, Korea, Republic of (chkim@kiost.ac.kr)
- 4Research Institute for Applied Mechanics, Kyushu University, Japan (hirose@riam.kyushu-u.ac.jp)
- 5Kongju National University, Atmospheric science, Korea, Republic of (eunchul.chang@gmail.com)
The East/Japan Sea (hereafter the East Sea) is one of the semi-closed marginal seas surrounded by Korea, Russia, and Japan. The Tsushima Warm Current (TWC) that is one of the major upper layer circulations flows into the East Sea through the Korea/Tsushima Strait (KTS). This TWC mainly bifurcates into three main branches in the southern part of the East Sea: the Nearshore Branch (NB), East Korea Warm Current (EKWC), and the Offshore Branch (OB). The upper layer circulations are greatly influenced by various external forcings such as wind stress, bottom topography, volume transport flowing through the KTS, and thermal forcing. Among them, the thermal forcing impact on the upper layer circulation of the East Sea is not well known. In this study, a three-dimensional numerical ocean model (RIAMOM) of Kyushu University is employed to investigate the impact of surface heat flux on the upper layer circulation of the East Sea. Numerical results show that the branching of the TWC is simulated regardless of applying wind stress. However, the EKWC that is one of the TWC branches does not appear without surface heat flux. Most of the TWC flows along the Japanese coast in the form of the NB. Furthermore, since there is no thermal interaction with the atmosphere, the heat supplied through the KTS tends to accumulate in the upper layer, thereby forming a thick upper layer in the overall East Sea. As the upper layer thickness increases, the TWC is significantly influenced by bottom topography. Therefore, most of the TWC flows along the developed continental shelf off the Japanese coast. In contrast, without the continental shelf, the TWC flows only along the Korean coast as a western boundary current regardless of surface heat flux. This result suggests that the surface heat flux can play an important role in controlling the bottom topographic and planetary beta effects on the upper layer circulation in the branching of the TWC.
Keywords: Tsushima Warm Current, East Korea Warm Current, Surface heat flux, bottom topographic effect, planetary beta effect
Acknowledgment: This work was funded by the Korea Meteorological Administration Research and Development Program under Grant KMI2022-01210.
How to cite: Kim, D., Shin, H.-R., Kim, C.-H., Hirose, N., and Chang, E.-C.: Effect of the sea surface heat flux on upper layer circulation of the East/Japan Sea, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6255, https://doi.org/10.5194/egusphere-egu23-6255, 2023.
