Comparison of in situ and remotely-sensed (SeaWiFS) chlorophyll-a in the Northwest Atlantic

Abstract

Field measurements of phytoplankton pigment (chlorophyll-a) from the Northwest Atlantic are compared with concurrent pigment concentrations derived from SeaWiFS data using NASA/SeaDAS algorithms known as Ocean Chlorophyll 2 (OC2) and OC4 (versions 4.1 and 4.3). The results showed broad agreement but estimates using the NASA algorithms tended to show uncertainties, with lower than in situ values at concentrations greater than 1 mg chl-a m⁻³. Regionally -, and seasonally-, adapted empirical corrections are developed in an attempt to reduce the bias. The magnitude of errors was quantified using linear regression. Further progress will require application of a theoretical regional ocean-colour model.