Measurements and Modeling of the Volume Scattering Function in the Coastal Northern Adriatic Sea.

Abstract

Measurements of the Volume Scattering Function (VSF) between 0.5° and 179° with an angular resolution of 0.3° were performed in the northern Adriatic Sea onboard an oceanographic platform at three different seasons, using the “Multi-spectral Volume Scattering Meter” (MVSM) instrument. Important differences were observed with respect to the commonly used Petzold’s functions. The comparison of the derived scattering, bp(L) and back-scattering, bbp(L) coefficients for particles with the measurements performed with the classical AC-9 and Hydroscat-6 showed agreement within 20%. The use of an empirical relationship for the derivation of bb(L) from β(ψ,L) at ψ=140° was validated for this coastal site although ψ=118° was confirmed to be the most appropriate angle. The low value of the factor used to convert β(ψ,L) into bb(L) within the Hydroscat-6 processing partially contributed to the underestimation of bb(L) with respect to the MVSM. Finally, the use of the Kopelevich model together with a measurement of bp(L) at L=555 nm allowed to reconstruct the VSF within about 35%.