North Pacific Ocean CO₂ disequilibrium for spring through summer, 1985-1989

Extensive measurements of CO₂ fugacity in the North Pacific surface ocean and overlying atmosphere during the years 1985-1989 are synthesized and interpreted to yield a basin-wide estimate of ΔfCO₂. The observations, taken from February through early September, suggest that the subtropical and subarctic North Pacific is a small sink for atmospheric CO₂ (0.07 to 0.2 Gton C (half year)^-1 for the region north of 15°N). Objective analysis techniques are used to estimate uncertainty fields resulting from constructing basin-wide contours of oceanic fCO₂ on the basis of individual cruise transects. The uncertainties are significant and imply that future sampling programs need to recognize that estimating oceanic uptake of anthropogenic CO₂ from ship-transect observations of oceanic fCO₂ alone will require very extensive sampling.