Atlantic Long-Term Oceanographic Mooring (ALTOMOOR)

Abstract

The Atlantic Long-Term Oceanogrphic Mooring (ALTOMOOR) has been maintained offshore Bermuda since 1993 as a testbed for the evaluation of new data telemetry technologies and new oceanographic instrumentation. It is currently a joint project between the Woods Hole Oceanographic Institution and the University of Southern California This report documents the WHOI contributions which have focused on the development of new data telemetry methods and new mooring technology. Details of the instrumentation evaluations will be published separately. A new inductively-coupled telemetry technology for ocean moorings has been developed and tested on ALTOMOOR. The inductive link uses standard, plastic-jacketed mooring wire as the transmission path for data generated at the individual instruments installed on the mooring. The signals are inductively linked to the mooring wire via toroids clamped around the wire, thus avoiding the need for multiconductor electromechanical cables terminated at each instrument. Seawater provides the electrical return path. The inductive modems send and receive data at 1200b/s. A controller in the surface buoy collects data from each of the subsurface instruments and forwards the data to shore by traditional satellite telemetry (Argos) and by short range radio using a nearby ship as a store and forward node. The buoy-to-ship link operates over about 2 km at 10kBytes/sec. When the ship docks, data are offloaded automatically to a computer on shore which can be accessed via the Internet.