[A-CG36] Extratropical oceans and atmosphere

[ACG36-03] Intercomparison of eddy-resolving ocean reanalyses around Japan

*Nobumasa Komori¹, Norihiko Sugimoto¹, Kent Kumeta¹, Hiona Mori¹, Yoshiaki Miyamoto¹, Naoki Hirose² (1.Keio University, 2.Kyushu University)

Keywords:Ocean reanalyses, western North Pacific, Kuroshio, Oyashio, oceanic fronts, mesoscale eddies

Ocean reanalysis datasets, created by assimilating observational data into numerical models, are becoming indispensable for studying past ocean variability. Increased computational power now enables us to conduct ocean reanalyses with a horizontal resolution of less than ten kilometers. In recent years, some operational centers have developed such "eddy-resolving" ocean reanalyses for regional or (quasi-)global oceans spanning several decades.
In this study, we compare three eddy-resolving ocean reanalyses—FORA-WNP30 (Usui et al., 2017), GLORYS12V1 (Lellouche et al., 2021), and BRAN2020 (Chamberlain et al., 2021)—for the western North Pacific around Japan. This region is characterized by oceanic fronts associated with the Kuroshio/Kuroshio Extension and Oyashio currents and contains detached mesoscale eddies. Our findings indicate that large-scale fields in the open ocean are highly similar due to the assimilation of observational data. However, significant discrepancies exist in mesoscale structures and in marginal seas.