Measurements of the Volume Scattering Function (VSF) were performed on water samples collected in the northern Adriatic Sea coastal area in the frame of the CoASTS time-series in the period 2004-06 using a prototype instrument (Lee and Lewis, 2003). The VSF was measured for angles going from 0.5 to 179° with a resolution of 0.3° at 443, 490, 510, 532, 555, 590 and 620 nm. Vertical profiles of absorption a, scattering b, and back-scattering bb (AC-9 and Hyd-6) were simultaneously performed. The values of bp and bbp for particles at 510 nm derived from the integration of the VSF varied between 0.2 and 1.7 m-1 for the first and between 0.004 and 0.045 m-1 for the latter whereas their ratio varied between 0.014 and 0.029. Significant differences were observed with respect to the Petzold functions. The Kopelevich model (1983) however, was shown to provide a good description (within 40%) of the measured VSF. The comparison of the derived bp and bbp with the same quantities measured with the AC-9 and Hyd-6 showed agreement within 20% and 25% for bp and bbp, respectively, with a general underestimation of bbp by the Hyd6. The use of the empirical relationship for the derivation of bb from a unique measurement of scattering at 140° as performed by the Hyd-6 was validated for this area although 117° was confirmed to be the most appropriate angle. Finally, the use of the Kopelevich model together with an AC-9 measurement of bp at 555 nm allows to reconstruct the VSF within about 35%.

BERTHON Jean-Francois;  LEE Michael;  SHYBANOV Evgeni;  ZIBORDI Giuseppe; 

2009-09-09

Office of Naval Research

JRC33615

https://publications.jrc.ec.europa.eu/repository/handle/JRC33615,