Meaning
Marine observation systems involve the placement of anchored instrumentation at specific offshore locations to record physical or chemical properties of the sea. Oceanographic moored deployments utilize a heavy base on the seafloor connected by a cable to a series of floats and sensors. These arrays allow for the continuous collection of data over months or years without the need for a manned vessel.
System Architecture
Buoyancy modules and high strength lines keep the instrumentation at precise depths within the water column. In oceanographic moored deployments, the tension on the cable must be calculated to withstand currents and surface waves. Acoustic release mechanisms allow the sensor package to be recovered by detaching it from the anchor upon a signal from the surface.
Each component must be treated to resist the corrosive effects of salt water and biological growth.
Field Operation
Vessel time for the installation and retrieval of these systems represents a large portion of a research or monitoring budget. Planning for oceanographic moored deployments requires a detailed survey of the seafloor to ensure the anchor sits on a stable surface. Coordination with local maritime authorities is necessary to prevent interference from fishing or shipping activities.
Successful recovery depends on the durability of the power supply and the integrity of the watertight housings.
Data Management
Loggers stored within the sensors record observations at fixed intervals for later analysis. Because oceanographic moored deployments often lack real time telemetry, the data is only accessible once the equipment is physically retrieved. This delayed arrival of information is a trade off for the high resolution and long duration of the records.
Modern arrays sometimes include satellite uplinks on the surface buoy to provide a steady stream of environmental updates.
