VARIABILITY OF DELTA-PCO(2) IN THE SUB-ARCTIC NORTH PACIFIC - A COMPARISON OF RESULTS FROM 4 EXPEDITIONS

Time-space variability of surface seawater pCO(2) is examined over the region (150 degrees W-180 degrees, 46 degrees N-50 degrees N) of the subarctic North Pacific where large meridional gradients of temperatur e and nutrient concentrations exist. The data were collected during fo ur trans-Pacific expeditions in three different years (1985-1987), but within the same 30-day period of the year (August-September). Systema tic measurement differences between the four data sets are estimated a s <10 mu atm. The inter-expedition comparison suggests that surface se awater pCO(2) in the study area is quite variable, with mean differenc es of up to 25 mu atm and local differences up to 60 mu atm. Spatial a nd interannual variability of surface seawater pCO(2) were found to co ntribute significant uncertainty to estimates of the mean Delta pCO(2) for the study area. Fluxes were calculated using Delta pCO(2) values from the four expeditions combined with gas exchange coefficients calc ulated from four different wind fields giving a range of -0.94 to +4.1 mmol CO2 m(-2) d(-1). The range of fluxes from the study area is scal ed to a larger area of the North Pacific to address how this variabili ty can translate into uncertainties in basin-wide carbon air-sea excha nge fluxes.