An Optical Instrument For Monitoring Suspended Particulates In Ocean And Laboratory

An optical sensor and submersible electronics unit has been developed for measuring particle concentrations in the ocean, rivers and laboratory. Particles are detected with an integrating scatterometer which consists of a modulated infrared emitter and photovoltaic detector. The instrument has programmable sampling modes for multiple applications and incorporates CMOS integrated circuits for low power consumption. For shipboard surveys, the instrument can be interfaced with CTD profiling systems and operated in a continuous sampling mode on rechargeable NICAD batteries. The burst mode is switch selected to synchronize sampling with self-recording instrumentation for long-term deployments of the instrument. We have deployed these instruments with acoustic current meters in ice-infested waters to monitor sediment transport; they have also been used to map plumes of: waste drilling fluids, sewage effluents and dredge spoils.