MEASUREMENT OF THE SPECTRAL ABSORPTION-COEFFICIENT IN THE OCEAN WITH AN ISOTROPIC SOURCE

Closed-form equations that describe the vector irradiance from an isot ropic source embedded in the ocean are rigorously derived from the ste ady-state radiative transfer equation. The equations are exact for a h omogeneous medium and are believed to be an excellent approximation al ong the vertical axis for a plane-parallel ocean. The equations are so lved for the absorption coefficient as a function of distance from the source. For clear ocean water, it is shown that vector irradiance mea surements alone provide sufficient information for an accurate calcula tion of the absorption coefficient. Measurements in Pacific water of t he vector irradiance from an isotropic source are presented, and the a bsorption coefficient is computed. The estimated value of the absorpti on coefficient from a linear least-squares fit to the data has a stand ard error of approximately 1%.