A comparison of particulate organic carbon (POC) from in situ and satellite ocean color data off the coast of Antarctica

Particulate organic carbon (POC) is a critical sink for atmospheric carbon in the ocean. Learning about the fluxes of carbon in the ocean is important, but still not fully comprehended. Estimating POC from ocean color satellite data is a vital tool for understanding the carbon cycle. POC algorithms need to be validated as frequently as possible because they use proxies to estimate a globally dynamic and complex geophysical parameter. In this study, three different algorithms were compared to in situ POC measurements for samples collected near the Antarctic Peninsula. In situ POC concentrations ranged from 79.0 to 232.2 µg/L while satellite POC estimations ranged between 16.0 and 244.4 µg/L for the same dates and locations. The mean absolute percent differences for the three algorithms ranged between 16.4 and 67.1%. No significant difference exists between the three algorithms and the in situ data. These results support the validation of all three of these algorithms in this study, although Algorithm 1 (A1, Table 1, Stramski et al. 2008) estimated POC with the smallest uncertainty.Summary of the particulate organic carbon (POC) algorithms used. (The units of POC are μg*L^-1. The remote-sensing reflectance, Rrs(λ), has units of sr^-1.)