INHERENT OPTICAL-PROPERTIES OF THE OCEAN - RETRIEVAL OF THE ABSORPTION-COEFFICIENT OF CHROMOPHORIC DISSOLVED ORGANIC-MATTER FROM FLUORESCENCE MEASUREMENTS

The quantitative relationship between the absorption and fluorescence emission of chromophoric (colored) dissolved organic matter (CDOM) has been determined along five cruise tracks in the western North Atlanti c Ocean, the Gulf of Mexico, and Monterey Bay, and includes Gulf Strea m, Loop Current, slope, shelf, and coastal waters. We present a protoc ol for the determination of CDOM fluorescence that will allow both int erlaboratory comparisons and the calibration of airborne fluorescence measurements. This protocol is based on the use of the water Raman sig nal as an internal radiometric standard and quinine sulfate as an exte rnal standard. This study demonstrates that when an appropriate and co nsistent procedure is used to standardize fluorescence measurements, t he fluorescence per unit absorption exhibits surprisingly little varia tion for diverse waters. The maximum variability observed between all sites was 36% and within the western North Atlantic the variability wa s only 12%. Algorithms are presented for retrieval of the absorption c oefficient of CDOM at 355 and 337 nm from shipboard or airborne measur ements of the water-Raman-normalized fluorescence emission resulting f rom 355- and 337-nm excitation.