Evaluation of Southern Ocean O2/Ar-based Net Community Production (NCP) Measurements
Poster Number:
87
Presenter/Primary Author:
Scott Doney Sea-air biological O2 flux assessed from measurements of surface O2 supersaturation in excess of that of Ar is used commonly to constrain net community production (NCP) in the upper ocean mixed layer. We evaluate the magnitude of potential errors in the O2/Ar method for the Southern Ocean using numerical experiments with two ocean biogeochemistry general circulation models. We find that biological O2 flux gives an accurate picture of the regional-scale patterns and trends in NCP. However, on local scales, violations of assumptions lead to significant, non-uniform differences between model NCP and biological O2. Errors arise from: 1) misalignment of biological O2 flux & NCP in time and space; 2) vertical O2 fluxes of oxygen across the base of the mixed layer. Comparison of model biological O2 fluxes against available surface O2/Ar data for various Southern Ocean regions also indicates overall good model-data agreement on regional scales.
