A new type of directional wave module to extend UK Smart Buoy measurement capabilities

To address the growing need for high frequency real-time data for effective monitoring and assessment of nutrient inputs and ecosystem response, Smart Buoy has been developed in the United Kingdom (UK). A number of the buoys have been deployed by the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) in the southern North Sea. The buoy carries a unique instrument payload including in-situ nutrient analyzers, chemical sensors, and a plankton/water sampler along with an array of bio-optical sensors. To date, collected meteorological and physical oceanographic data have been limited to standard meteorological data, high precision salinity and temperature measurements, and suspended load data. Smart Buoy utilizes a 1.9 m outside diameter toroid hull with a structural frame that extends approximately 3 m above the water surface and somewhat over 1 m beneath the water surface depending on a buoy's configuration and sensor suite. An intelligent data acquisition and control unit employs distributed data acquisition techniques to acquire data from several linked autonomous sub-modules. Doing this makes the system robust and able to withstand even catastrophic failures of modules. Data telemetry is by radio or satellite. To fully characterize the physical environment that acts as a driver for the biological and chemical environment, a new Directional Wave Module (DWM) has been developed as a module for Smart Buoy. With DWMs, the buoys can also be better used for marine weather monitoring. The central controller design approach facilitates the optional addition of the DWM to particular buoys. The module has two small components, a self-contained underwater pressure housing with data acquisition and processing electronics as well as buoy motion sensors and a superstructure-mounted three axis magnetometer. So that the DWM can be used with differently configured buoys, data are processed optionally by either a wave particle following or a wave slope following approach. Data acquisition and analysis approaches follow state-of-the-art procedures. Real-time directional wave spectra, and resultant wave height, period, and direction parameters, are transferred to the Smart Buoy controller by serial interface for relay to shore. The controller, or optionally the DWM, also stores buoy motion time series data in high-capacity non-volatile memory for possible re-analyses for special applications. The DWM has been tested by wave simulations. Results from a major UK field inter-comparison will be available soon. The DWM is a new type of intelligent wave sensor that may be used with virtually any buoy hosting a main controller or buoy system that utilizes a serial input.