SOMSS - A new instrument for medium resolution spectral measurements of underwater optical properties using fibre optic sensors

摘要

The Southampton Oceanographic Multi-Spectral Sensor (SOMSS) is an instrument for the measurement of underwater spectral radiance, irradiance, transmittance and scattering. The instrument uses multimode, step index, optical fibres to transmit radiation collected by the optical sensor heads to a central instrument body. Spectral measurements are carried out using a spectrograph which images input fibres from the sensors onto a full frame, two-dimensional CCD camera. The CCD camera and the internal light sources for transmittance and scattering measurements are operated by a PC compatible controller and the system has been designed for unattended operation. The use of fibre optic connectors to couple the optical sensors to the instrument allows the instrument to be reconfigured to meet a number of measurement requirements. The main design objective has been to provide spectral data with spectral resolutions approaching those expected for the next generation of remote sensing platforms for ocean colour monitoring such as SeaWIFS and MERIS. Dependent upon sensor type, spectral resolutions from 2 to 8 nanometres have been achieved over a spectral range from 400 to 700 nanometres. This instrument has been developed under a joint project between the Optoelectronics Research Centre and the Department of Oceanography, both at Southampton University, as part of the NERC funded Sensor and Instrument Design for Autosub and LOIS (SIDAL) project.