Accuracy assessment of bio-optical model in turbid case II waters

Both radiative transfer model and bio-optical model can be used to simulate the remote sensing reflectance for waters.Generally,the radiative transfer model is of high accuracy,but it is too sophisticated to retrieve water quality parameters(WQPs).The bio-optical model is simple and easy to be implemented in retrieving WQPs,but its accuracy in simulating turbid case II waters is still unknown.In this study,the radiative transfer model(i.e.Hydrolight model) and bio-optical model(i.e.Lee model) were both used to generated a large number of spectra data with different combinations of WQPs.Using the spectra yielded by Hydrolight model as true value,we assessed the simulation accuracy of the Lee model in turbid case II waters.Results show that(1) except for the non-phytoplankton suspended substance dominated waters,results of Lee model can be acceptable with overall relative error less than 10%;(2) larger errors in Lee model occurred in the bands for Chl.a estimation than other bands;(3) simulation accuracy of remote sensing reflectance just below water surface is consistent with that just above surface.