A fixed-thickness layer of the water column, often 0.25 to 2 m, for which an ADCP reports one velocity. The first bin starts beyond a blanking distance close to the transducer where ringing spoils the data, and bins near the surface or bottom can be contaminated by sidelobe reflections over roughly the last 6 percent of range for 20 degree beams. Choosing bin size trades vertical detail against noise.
Top two bins are junk from sidelobe off the surface, use bin 14 down for the near-surface current.
Also heard as
- depth cell
- cell
Related terms
ADCP
Acoustic Doppler current profiler: an instrument that measures current speed and direction at many depths at once.
Current ellipse
The ellipse traced by the tip of a tidal current vector over one cycle, showing direction and speed at each stage.
Tidal current
The horizontal flow of water that accompanies the rise and fall of the tide.