Acoustic Doppler current profiler

In recent years, more functionality has been added to ADCPs (notably wave and turbulence measurements) and systems can be found with 2,3,4,5 or even 9 beams.Depending on the nature of the deployment the instrument usually has the ability to be powered from shore, using the same umbilical cable for data communication.The method is in use by hydrographic survey organisations across the world and forms an important component in the stage-discharge curves used in many places to continuously monitor river discharge.In this case the velocity of the vehicle is combined with an initial position fix, compass or gyro heading, and data from the acceleration sensor.[5] ADCPs with pulse-to-pulse coherent processing can estimate the velocity with the precision required to resolve small scale motion.A typical approach is to fit the along beam velocity to the Kolmogorov structure configuration and thereby estimate the dissipation rate.The application of ADCPs to turbulence measurement is possible from stationary deployments but can also be done from moving underwater structures like gliders or from subsurface buoys.The two major advantages of ADCPs is the absence of moving parts that are subject to biofouling and the remote sensing aspect, where a single, stationary instrument can measure the current profile over ranges exceeding 1000 m. These features allow for long term measurements of the ocean currents over a significant portion of the water column.As any acoustical instrument, the ADCP contributes to noise pollution in the ocean which may interfere with cetacean navigation and echolocation.
ADCPs with three beams resolve the three components of velocity. (Models Aquadopp Profiler 1MHz and 0.6 MHz, Nortek)
Head of an ADCP with four transducers (Model WH-600, RD Instruments)
Underwater photo of an ADCP with five transducers (Model Signature1000, Nortek)
The AWAC (Acoustic Wave and Currents) is a type of ADCP specifically designed for surface wave height and direction.
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