A model that relates the coefficients of absorption (<i>a</i>) and backscattering (<i>b</i><sub><i>b</i></sub>) to diffuse attenuation (<i>K</i><sub><i>d</i></sub>), radiance reflectance (<i>R</i><sub><i>L</i></sub>), and the mean cosine for downward irradiance (μ<sub><i>d</i></sub>) is presented. Radiance transfer simulations are used to verify the physical validity of the model for a wide range of water column conditions. Analysis of these radiance transfer simulations suggests that absorption and backscattering can be estimated with average errors of 1% and 3%, respectively, if the value of μ<sub><i>d</i></sub> is known with depth. If the input data set is restricted to variables that can be derived from measurements of upward radiance (<i>L</i><sub><i>u</i></sub>) and downward irradiance (<i>E</i><sub><i>d</i></sub>), it is necessary to use approximate values of μ<sub><i>d</i></sub>. Examination of three different approximation schemes for μ<sub><i>d</i></sub> shows that the average error for estimating <i>a</i> and <i>b</i><sub><i>b</i></sub> increases to ~13%. We tested the model by using measurements of <i>L</i><sub><i>u</i></sub> and <i>E</i><sub><i>d</i></sub> collected from case II waters off the west coast of Scotland. The resulting estimates of <i>a</i> and <i>b</i><sub><i>b</i></sub> were compared with independent <i>in situ</i> measurements of these parameters. Average errors for the data set were of the order of 10% for both absorption and backscattering.
© 2003 Optical Society of America
David McKee, Alex Cunningham, and Susanne Craig, "Estimation of Absorption and Backscattering Coefficients from in Situ Radiometric Measurements: Theory and Validation in Case II Waters," Appl. Opt. 42, 2804-2810 (2003)