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Intercomparison of sea level variation across the Tsushima Strait among tide gauge data, a coastal altimetry product and an ocean reanalysis FORA-WNP30

N. Hirose (JMA/MRI), N. Usui (JMA/MRI), T. Wakamatsu (JAMSTEC), Y. Tanaka (JAMSTEC), T. Toyoda (JMA/MRI), Y. Fujii (JMA/MRI), Y. Takatsuki (JMA/MRI), T. Kuragano (JMA/MRI), and M. Kamachi (JAMSTEC)

The surface circulation of the Japan Sea is affected by the variations of heat, salt, and moment through the straits connected to the adjacent sea. Warm saline water enters the Japan Sea through the Tsushima Strait (TSM) and flows mostly out through the Tsugaru and Soya Straits.
Recently, an ocean reanalysis FORA-WNP30 (Four-dimensional variational Ocean ReAnalysis for the Western North Pacific over 30 years) has been produced using a 4-dimensional variational ocean data assimilation system, MOVE-4DVAR with an eddy-resolving ocean general circulation model. We found that low-frequency variability of volume transport through the TSM is largely in phase with that of the upper ocean heat content in the Japan Sea on interannual to decadal time scales.
To evaluate the reproduction of volume transport through the TSM in FORA-WNP30, we compare the sea levels in FORA-WNP30 with independent data such as tide gauge data and altimetry data around coastal areas. Sea level variation in FORA-WNP30 is largely consistent with tide gauge data around the Japan coast. In addition, we plan to intercompare the sea levels across the TSM among tide gauge data, a coastal altimetry product and FORA-WNP30.