Design of a modern optical fibre spectral transmissometer and a scattering meter

Abstract

This paper describes an in situ new technology optical fibre-based system designed to yield simultaneous measurements of the spectral attenuation coefficient, c(λ), and the volume scattering function at 120◦ backwards on ocean waters, within the spectral range 400–800 nm. The volume scattering function at 120◦, β(120◦, λ), will be used to derive the backward scattering coefficient, bb(λ). Optical and mechanical designs are presented. The considerations leading to the design of the instrument, its capabilities and the unique features it incorporates are discussed. Methods for absolute calibration of the instrument are presented.