抄録
Estimation of the depth of sunlight penetration and upward irradiance from the depth in the ocean and the coastal water were made. Although chlorophyll-a contentc can be calculated by sea surface radiant spectrum, the effective depth of light Penetration is different by water quality itself. Optical information from secchi disk depth seemed to be very low. The 90 percent of surface upward irradiance come from the slightly shallower than the secchi disk depth and the 70 percent of it come from the half of scchi disk depth. So, the optical information depth has different value by
each areas and seasons.
