Deployment

In order to collect useful measurements that actually resolve the turbulence statistics consistent with the application of the Kolmogorov hypotheses of isotropic turbulence, it is important to configure and deploy your instrument using best practices. In setting up your instrument, it is recommended that consider the following recommendations:

1. Environmental conditions
   • Ensure measurement velocity range is sufficient for anticipated background flow, tides, surface waves and internal waves
   • For pulse-pulse coherent measurements, minimise potential issues due to phase wrapping by setting the ambiguity velocity to be larger than the maximum flow speed that is expected
   • Ensure that spatial parameters (number of bins and bin size) are selected so that several bins [SHOULD WE QUANTIFY THIS] are within the expected inertial subrange that extends from the Kolmogorov scale [math]\displaystyle{ L_K }[/math] to the Ozmidov scale [math]\displaystyle{ L_o }[/math] [IS IT POSSIBLE TO LINK TO APPROPRIATE TABLE?]. Use anticipated stratification and turbulence levels to determine [math]\displaystyle{ L_K }[/math] and [math]\displaystyle{ L_o }[/math].
2. Velocity measurements
   • Record in Beam coordinates​
   1. Maximise velocity accuracy whilst minimising averaging (pings per ensemble)
   2. Select [math]\displaystyle{ \varepsilon }[/math] estimate observation period (period over which structure function is evaluated) consistent with fundamental requirement of stationary statistics
   3. Maximise the number of profiles (ensembles) per [math]\displaystyle{ \varepsilon }[/math] estimate observation period to improve statistics
   4. Instruments with an extra (vertical) beam typically allow a different configuration to the angled beams
3. Motion control​ during deployment
   1. Sufficient buoyancy on frame to hold position well, but not obstructing beam path ​
   2. Consider also nearby moorings and frames to reduce/avoid interference.
   3. If the mooring can move, collect depth (pressure sensor on ADCP or adjacent instrument) and orientation data (heading, pitch and roll) at the same frequency as the velocity profiles data. Consider high resolution add-on’s such as AHRS. ​
   4. Mooring design should consider impact of knock-down on location of observations in the water column
4. Power and Storage ​for self-contained deployments
   1. Planned deployment duration
   2. Manufacturer’s expected energy consumption versus battery capacity at expected temperature
   3. Manufacturer’s expected memory required per recorded profile (ensemble) versus available memory
   4. Extending interval between observation periods (burst mode) reduces duty cycle allowing longer duration deployment but with reduced temporal resolution of [math]\displaystyle{ \varepsilon }[/math] estimates

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1. ADCP Hardware
2. ADCP Environment

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