Optimal Precursor Triggering Kuroshio Large Meander Decay Obtained in a Regional Ocean Model

Abstract

The Kuroshio is the well-known western boundary current formed by the North Equatorial Current (NEC) flowing northward. When the Kuroshio flows along the southern coast of Japan, its path exhibits three remarkable states (Kawabe, 1995;Taft, 1972): the typical large meander (tLM) path, the offshore nonlarge meander (oNLM) path and the nearshore nonlarge meander (nNLM) path, as shown in Figure 1. Usually, according to whether the LM occurs, these paths south of Japan are classified into two categories: the large meander (LM) path and the nonlarge meander (NLM) path. Long-term observation data indicate that Kuroshio path variations have significant interdecadal characteristics. Once the Kuroshio is in a certain path, it will persist from a year to a decade, but the transition between two paths occurs over several months (Kawabe, 1995). Kuroshio path variations impose important effects on climate, fisheries, and navigational safety in the North Pacific (Hayasaki et al., 2013;Nakamura et al., 2012;Xu et al., 2010). Therefore, it is important to explore its physical dynamics and accurately predict the Kuroshio path.