Author(s): Chihiro Kashima; Yusuke Nakatani

Linked Author(s):

Keywords: Numerical simulation; SCHISM; The Seto Inland Sea; Kuroshio; Ocean boundary

Abstract: Understanding water exchanges with the open ocean is critical for understanding the water environment of coastal sea areas. The Seto Inland Sea (SIS), Japan's largest enclosed sea, is connected to the Pacific through two east-west channels. Water exchange with the open ocean plays a vital role in the water quality of SIS and is known to depend on the flow path of the Kuroshio. Therefore, accurately reflecting the open ocean's influence is essential. Although numerical simulations have been used to solve water-quality problems in SIS, there needs to be more research on the selection of ocean boundary conditions. This study focuses on water exchanges between the open ocean and SIS to investigate the effects of different ocean boundary conditions on water temperature and salinity. In order to achieve the research objective, numerical simulations were carried out by using the three-dimensional unstructured grid hydrodynamic model SCHISM. We used the two ocean data products as ocean boundary conditions, and the results of both cases were then compared. The simulation results showed that the ocean boundary conditions produce differences in the reproducibility of the Kuroshio current path. These differences alter the throughflow from the open ocean and have effects on the water temperature and salinity in the SIS. Furthermore, a significant difference in the cold-water creep at the bottom layer was observed near the continental shelf. This cold-water creep from the open ocean significantly affected the bottom water temperature in the eastern part of the SIS.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0785-cd

Year: 2023