2020 Volume 58 Issue 1-2 Pages 17-33
To examine seawater exchange in Matsushima Bay, we analyzed monthly tempera ture and salinity data, obtained by the Miyagi Prefecture, and temperature monitoring data provided by the Sena and Varns Corporation. The difference in surface temperature, between water inside and outside of the bay, is larger in early summer and late summer, and decreases in mid summer, indicating two peaks in the warming season. A temperature fluctuation with a several-day period was strongly correlated to the northwest-southeast wind component, which dominated from early summer to fall. The correlation indicates that the temperature decrease was induced about 2 days after southeastward wind events. In order to clarify these mechanisms, we employed the Regional Ocean Modeling system (ROMS) using observed atmospheric data. After reproducing the temperature variation from spring to fall. we found that over a several-day period, wind induced seawater exchange and variation in the temperature difference between water inside and outside of Matsushima Bay. Monitoring data and model results confirmed that an internal tide was generated in the bay during the formation of a thermocline that occurred after the southeastward wind. These results indicate that wind-induced seawater exchange occurs in Matsushima Bay.