Spatial and temporal variations in the sea surface pCO2 and air-sea CO2 flux in the equatorial Pacific: model sensitivity to gas exchange and biological formulations

X. J. Wang
2010 Biogeosciences Discussions  
The equatorial Pacific Ocean is responsible for the interannual variability of the global ocean-atmosphere CO 2 fluxes. However, most ocean carbon models significantly underestimate the interannual variability of the regional ocean-atmosphere CO 2 fluxes. A basin-scale ocean circulation-biogeochemistry model is employed to investigate the 5 uncertainties associated with the choice of gas exchange formulation, and to assess the implications of the choice of ecosystem model. Using four different,
more » ... ing four different, quadratic and cubic relationships of the gas transfer velocity with wind speed yields small differences in the integrated sea-to-air CO 2 flux (0.32 to 0.42 Pg C yr −1 ), but large differences in the averaged ∆pCO 2 (44 to 73 µatm) for the area of 150 • E-90 • W, 10 • N-10 • S. While the 10 choice of gas exchange formulation primarily influences the magnitudes, the choice of ecosystem model has a broader influence on the spatial and temporal variations in modeled carbon fields in the equatorial Pacific Ocean. Particularly, employing an ecosystem model without a dissolved organic pool overestimates the interannual variability in net community production, leading to under-estimated interannual variability 15 of the basin-scale sea-to-air CO 2 flux.
doi:10.5194/bgd-7-3879-2010 fatcat:kcxzrvijqfgptavnqbiebq5lmm