Fig. 3

Non-tidal variations in ocean bottom pressure (OBP). a A comparison under equivalent water thickness to OBP. The blue line denotes the OBP estimated by the ocean model used in this study, which was developed by the Japan Meteorological Agency (Usui et al. 2006). The OBP was estimated at a longitude of 146°E and a latitude of 39.2°N. The red and black lines represent in situ observations from the OBPR-B site and another ocean model, respectively (Fig. 3 in Matsumoto et al. 2006). For easier comparison, the other plots were removed from the original figure in Matsumoto et al. (2006). b The daily OBP calculated by the JMA ocean model at the sites marked H2–6 in Fig. 1b. The orange curve on H2 denotes a 5-year running average. The superimposed pink bars denote periods of large-scale meandering of the Kuroshio Current, as reported by the JMA. It can be observed that the OBPs along the coast in the Tokai district increase (decrease) with the initiation (end) of the events. c The same as (b), but the OBP values from 1980 to 2013 are plotted cyclically against months