Bio-Optical Sensors Onboard Autonomous Profiling Floats

Abstract

The perspective of an array of thousands of floats drifting in the world ocean offers the possibility to monitor global ocean currents via the distribution of oceanographic parameters like temperature and salinity (WOCE – ARGO programme). Deploying these floats with advanced bio-optical sensors for the detection of bio-geochemical parameters offers a potential for large scale assessment of the pelagic primary productivity and the bio-geochemical processes involved. Technical specifications to be met by these sensors will be: low power consumption, long-term stability and reliability, standardized interfaces and protocols together with an intelligent data handling. However, these requirements also demand sophisticated capabilities of the float as a platform. Enhanced interfaces, algorithmic power and memory including new telemetry and docking solutions are necessary to provide a flexible and yet reliable platform for bio-geochemical sensors onboard floats. Within this work an overview of bio-optical sensors, which were integrated in autonomous profiling systems, will be given. This introduction will be followed by first results from hyperspectral irradiance and radiance data from the Navigating European Marine Observer (NEMO) float which were obtain during a two-day lake experiment. Finally, future integrations of sensors and general requirements for floating profiling drifter in the context of coastal and open ocean observatories will be discussed.