Page 44: of Marine Technology Magazine (September 2016)

level are water quality sensors. On the seabed, about 100 m from the buoy, is a tripod. As well as water quality sensors, it carries a 600 kHz Teledyne RDI ADCP equipped with

NEMO waves for in-situ processing. The ADCP simultane- ously pro? les currents and processes directional wave spec- tra in-situ. Combining both currents and waves in a single compact package simpli? es operations. Using battery power allows the measurement of waves every two hours over a six-month deployment. Using a bottom-mounted ADCP for measuring waves, rather than a surface buoy, can have key advantages. It has been shown that ADCP wave mea- surements compare favorably with competing techniques.

Mounted on the bed, the equipment is safe from damage due to collisions by shipping. Also AIMS avoids frequent maintenance trips to remove fouling by tropical birds. Both had been problems while using wave buoys.

Communication Links

Access to the seabed ADCP’s data is achieved using acoustic telemetry through water to the surface buoy. The link is via a Teledyne Benthos ATM916 acoustic modem.

Every 30 minutes, the near-surface modem polls the tripod (Photo: Craig Steinberg)

The sea? oor tripod installed by y y y y y y y y y y

AIMS at the entrance to Port r r r r rt r r r r

Darwin. It carries a 600 kHz Tel l l l l le- e e e e e e e e dyne RDI ADCP equipped w w w w wit it it it it it i i i i h

NEMO waves, Teledyne Benth th h h h th h h hos

ATM916 acoustic modem, and a suite of water quality sen n n n n n n nsors.

The ADCP simultaneousl sl l sl l sl sl sly y y y y pro- ? les currents and proce e e e e e e ess s s s s s s es di- rectional wave spectra a a a a a a a i i i i i i i in-situ.

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