Bottom water circulation in the western equatorial Pacific as inferred from carbon tetrachloride observations

Abstract

Hydrographic and tracer data from the western equatorial Pacific, collected during cruise 113 of R/V Sonne in October-November 1996, are discussed in the context of spreading of lower Circumpolar Deep Water (ICDW). The horizontal distribution of CCl 4 and other properties indicate a deep western boundary current north of the Caroline Seamounts. Elevated concentrations of CCl 4 at the bottom show that a small fraction of ICDW in this region is younger than about 70 years. This age is used to infer a minimum spreading rate of about 0.8 cm/s for the young components of this water mass. The current appears to bifurcate at about 143°E into topographically guided northward and westward currents.