Abstract: Many in-situ data indicate that the vertical stratification of the inherent optical properties and optical active constitutes in euphoric depth is a common phenomenon in most ocean water. Most of satellite retrieval algorithms of the optical constitutes concentration are, however, based on the assumption of homogeneous ocean water, especially for empirical retrieval models, which are usually based on the statistical relation between the reflectance spectral of surface and the depth-averaged constitute concentration or that of a certain depth. Using the underwater optical radiative transfer model, the influences of vertically stratified concentration of chlorophyll and suspended sediment matter on the irradiance ratio at the depth of 0^- m are respectively analyzed. The two computation formulas of depth-weighted equivalent concentration of stratified water and their responding irradiance ratio at 0^- m depth are then compared. The results indicate that the primary error sources is the light penetration depth and the intensity of stratification: the deeper the penetration and the more distinct stratification, the greater the effect of stratified water on the value of irradiance ratio at 0^- m depth, as well as the error of depth-weighted equivalent concentration. Gordon’s computation results of equivalent concentration are more accurate, and the Zaneveld ’s results overestimate the equivalent concentration of stratified water.

Key words: stratified water bodies, Monte Carlo, weight function, depth-weighted equivalent concentration