|Finally, we look
at tides as another source of high-frequency variability in the ADCP
data. For the WAP region, the
strongest predicted tidal currents are diurnal topographic vorticity waves
along the shelf break. Part of our task is to improve the tidal models of
this region, but we need the revised bathymetry and data from the moorings
before we can do this.
|This plot shows
the RMS diurnal-band velocity for WHOI surface drifter #4. Dick Limeburner provided these data. The left hand panel codes this value by
size of the dot, and gives a value once per day. It only shows points where there are enough
ARGOS position data to do a good fit. The upper right panel shows U and V
components for the buoy motion. You
can see that peak currents are about 15 cm/s.
The lower right panel shows water depth under the buoy track,
interpolated from our tide model grid (CATS01.02).
|The main point
of this figure is to show that there are strong currents associated with
tides in some regions. So, if we want
to use the ADCP data to look at mean circulation over the WAP region, we need
to think about possibly large signals from near-inertial oscillations and