PHYSICAL
ADCP
Between each chosen station, an on-board ADCP (Acoustic Doppler Current Profiler)
was used to give magnitude and direction measurements of flow velocity; it can also
give an indication of the backscatter in the water column. These can be pieced together
to give a clear view of the water stretching out from Plymouth, and potentially combine
with temperature readings from the CTD to give an indication of a possible tidal-mixing
front. In general, the flow velocity increases as you head away from the mouth of
the estuary seen by the negligible velocities in figure ?. This then steadily increases
in the next figure shown by the shifting of colour towards the red end of the spectrum
(seen on the scale bar). After plateauing around 0.2m/s for a large period of time,
the flow velocity suddenly increases to 0.45m/s on the transect between station 4
and the first location of station 5 (figure ?). This point is just north of Eddystone
lighthouse and so the area of increased velocity is actually an eddy created by the
diffraction of water around Eddystone and subsequent turbulence. Past this point
and towards the last station (figure ?), the velocity remains relatively high at
around 0.2m/s, but does still contain patches of higher velocity which could be elements
of eddies formed previously which have started to dissipate away.
