Low-frequency variations of the Eastern Subtropical Front in the North Pacific in an eddy-resolving ocean general circulation model: roles of central mode water in the formation and maintenance

Abstract

Temporal variations (1960–2005) of the Eastern Subtropical Front (ESTF) in the North Pacific are investigated using historical-run output data of the eddy-resolving Meteorological Research Institute Community Ocean Model, forced by atmospheric reanalysis dataset. Simulated ESTF is distributed in a region of zonal band of 24°N–30°N east of the International Date Line, and is located at the southern boundary of the central mode water (CMW) north of the front. The ESTF intensity clearly shows an interdecadal variation with a timescale of about 20 years. This variation is associated with that in the potential vorticity of CMW, which originates in the CMW formation region farther north about 3 years earlier due to changes in the surface wind forcing.