The RITS/CO2 1988 cruise began on 6 April (Day 97) aboard the NOAA ship Oceanographer. The ship sailed from Dutch Harbor to the south along 170° W to American Samoa, arriving on 5 May (Day 126).
Atmospheric f(CO2) was highest near to the north (357 µatm) and generally decreased to ~ 335 µatm to the south along this track. Seawater f(CO2) values were low out of Dutch Harbor, but rose to 384 µatm near 48° N and then dropped gradually to <300 µatm near 34° N. This undersaturation persisted as far south as 10° N. The surface waters across the equator from 10° N to 6° S were supersaturated by as much as 96 µatm relative to the atmosphere. Near 6° N the f(CO2) values dropped sharply to undersaturation which persisted into Samoa. The mean percent standard deviation of the standard gases in this leg was 0.60%.