The RITS/CO2 1987 cruise was a continuation of the TEW-3 cruise, beginning on 29 July (Day 210) from Kwajalein. The cruise track continued north along 165° E to 50° N and then east into Dutch Harbor, Alaska. After a brief stop in Dutch Harbor on Days 233/234, the ship continued east along 50° N and then into Seattle, Washington on 28 August (Day 240).
Atmospheric f(CO2) values were steady at 334 µatm out of Kwajalein, but ranged from 330 to 343 µatm along the cruise track. Surface seawater CO2 was supersaturated from Kwajalein north to 36° N. The f(CO2)sw dropped sharply to 264 µatm near 40° N and remained undersaturated until the ship diverted from its eastward track north into Dutch Harbor. After the ship returned to 50° N, f(CO2)sw returned to undersaturation. Values climbed to 375 µatm near 50° N, 152° W and then decreased to near- or undersaturation as the ship moved east and into Seattle. The mean percent standard deviation of the standard gases on this leg was 0.32%.