Bio-Optical characteristic of Case-2 coastal water substances in Indonesia Coast

The results of our study in the bio-optical characteristic of mixed water substances or referred as water leaving radiance of chlorophyll-a in case-2 water. Apparent optical properties of chlorophyll-a (Chl-a) influence by others water constituents eq, particle backscattering, and yellow substances absorption coefficients. We studied varies Chl-a concentration from 0.001 µg/1-65.0 ug/l, mixed by suspended particle (SS) concentration from 0.01 mg/150.0 mg/l, and yellow substances absorption coefficients (ay) from 0.001 m-5.0 m. We used the simple radiative transfer equation in seawater method to simulate the Normalized water leaving radiance (NLw) of Chl-a. NLw of Chl-a with concentration less than 1 µg/l and less influence from other substances similar to NLw of pure sea water characteristic. This high reflected at blue band. Otherwise, Chl- a concentrations more than 1 µg/l, are similar to the absorption characteristic of Chl-a with fluorescence peak at 680 nm. The Cross characteristic (Hinge point) occurs at 530 nm. Higher SS concentration causes NLw characteristic of Chl-a change, where hinge point moves toward the longer wavelength. Higher yellow substance absorption coefficients cause NLw characteristic of Chl-a has strange behavior. To keep the NLw Chl-a characteristic, SS concentration should be no more than 1 mg/l, and ay coefficient no more than 0.01 m.