Mean zonal currents below 1500 m near the equator, 159°W


  • Eric Firing


Recent current measurements have shown that the subthermocline equatorial circulation in the central Pacific is considerably more complicated than had been thought. Below 1500 m depth on 159°W there are three currents south of the equator that appear to be permanent. Eastward currents are found at 1700 m and 3100 m, and a westward current is found at 4000 m. The 1700-m current is at the southern edge of the 3°S to 3°N range of current measurements, so its meridional extent and its transport are unknown. The 3100-m and 4000-m currents have 16-month mean transports of about 6 − 7 × 106 m3 s−1. All three of these currents may be important components of the general circulation.