A novel method to estimate DOC concentrations from CDOM absorption coefficients in coastal waters

Abstract

[1] A novel method to accurately retrieve DOC concentrations (±4%) from CDOM absorption coefficients, ag(λ), at λ = 275 and 295 nm is presented. By using these two wavelengths, the method exploits useful information about the ratio of ag(λ) to [DOC] contained in the 275–295 nm spectral slope coefficient, S275−295. This approach was developed using data (n = 222) collected on a seasonal basis in surface waters of the Northern Gulf of Mexico. The approach is demonstrated to accurately and consistently estimate [DOC] for all seasons and for a broad [DOC] range of 63–611 μM. Application to coastal waters of the Beaufort Sea (n = 33) demonstrated that similar performance can be expected in other river-influenced ocean margins after parameterization using local data. Applicability to other marine environments remains to be tested but such assessment can be pursued immediately where appropriate data have already been collected.