Inherent Optical Properties of the Irish Sea Determined from Underwater Irradiance Measurements

The results of four-channel irradiance meter measurements at 41 stations in the Irish Sea are presented. Diffuse attenuation (K) is least and reflection (R) is greatest in the green channel (550 nm). A very good relationship exists between the attenuation coefficient at this wavelength and the estimated photosynthetically active radiation (PAR) attenuation using all four channels:K(PAR)=0•01+1•11K(550) Absorption and scattering coefficients (aandb, respectively) have been derived from the observations using the results of a Monte Carlo model. Scattering coefficients are generally (but not invariably) larger than absorption coefficients in these waters (0•5