Evaluation of fluorometrically-derived chlorophyll <i>a</i> as a satellite ocean color validation product using statistical metrics

The fluorescence of chlorophyll <i>a</i> (Chl<i>a</i>) has long been considered a reliable estimate of phytoplankton biomass in aquatic environments. The in vitro fluorometric method for measuring Chl<i>a</i> is a simple, fast, and cost-effective way to estimate phytoplankton biomass. High performance liquid chromatography measurements (HPLC) of Chl<i>a</i> (HChl<i>a</i>) have been used historically for ocean color validation. The applicability of fluorometrically-derived Chl<i>a</i> (FChl<i>a</i>) to satellite ocean color validation has not been fully evaluated. To this end, we developed statistical metrics to evaluate the uncertainty of fluorometric measurements of Chl<i>a</i> by comparing them to coincident measurements made by HPLC. The distribution of uncertainties demonstrates occasional trends in the discrepancies between FChl<i>a</i> and HChl<i>a</i>, from which we developed a set of recommendations for future collection and validation efforts.