1999년 동태평양 적도해역 관측

Abstract

In November 1999 a hydrographic survey was carried out in a section from $5\\\\\\\\deg$N to $3\\\\\\\\deg$S in the eastern along $125\\\\\\\\deg$W. Velocity profiles showed four zonal and three meridional flow cores, indicating the equatorial zonal currents and the flow associated with the tropical instability waves. Water property sections showed that the warm and fresh surface water moving southward from the northern part formed a sharp thermal front at $2.1-2.2\\\\\\\\deg$N. The cold and saline water subducted beneath the front and continued to the north to $4.5\\\\\\\\deg$N, deepening to the thermocline depth. The speed of the saline water subduction reached up to 55 cm/s at 80 m depth at $3.2\\\\\\\\deg$N and the northward meridional flow at this location appeared down to 300 m depth below the thermocline. Dissolved oxygen (DO) data agreed well with the observations from T-S and velocity fields. This suggests that DO can be a good tracer to distinguish water masses in this complicated region. The features of Chlorophyll {\\\\\\\\it a} and other biochemical materials will be also presented.