Biases in the in situ measurement of particulate organic carbon and its effect on the calibration and validation of ocean color sensors.
As part of an ongoing effort to develop standardized protocols, we measured near-surface POC during the 2017 P06 GO-SHIP campaign across the South Pacific Gyre and into the Chilean Upwelling. In situ POC corrected for filter blank was almost always lower than ocean color derived values--satellite values had a ~43% bias above in situ. The implication, if proven generalizable, is that current POC algorithms based on non-corrected data might be overestimating this parameter. Furthermore, differences in the extent of the POC overestimate across ocean ecosystem trophic condition has serious ramifications for interpreting past and current measurements applied to derive C export. Results from this investigation will help improve estimates for POC from ocean color and their assimilation into models and CDRs.