Abstract:
We present velocity observations from a shipboard acoustic Doppler current profiler (ADCP) on
R/V Wecoma during cruise W0108a (6-25 August 2001). The cruise was a component (Survey
II) of the Coastal Ocean Advances in Shelf Transport (COAST) experiment. The ADCP was an
RD Instruments hull-mounted 153-kHz narrowband unit. Data were collected nearly continuously
using an ensemble averaging interval of 1 min and a vertical bin length of 8 m. This implies
an inherent short-term random uncertainty of 2 cm/s for each data point; this uncertainty is
reduced with additional space or time averaging. To reference the velocities to earth coordinates,
we used GPS navigation in combination with the ship's gyrocompass and a GPS attitude
system. Our processing methods are generally standard ones, primarily making using of the
CODAS software package as described at http://ilikai.soest.hawaii.edu/sadcp. Overall ADCP
data quality for the cruise was excellent. To produce the vector maps here, we applied 5 km spatial
averaging. For the sections, we contoured using a two-pass Barnes method with horizontal
(vertical) smoothing of 5 km (24 m) and 2.5 km (12 m) for the first and second passes. An online
version of this report is available at http://damp.coas.oregonstate.edu/coast/adcp. In addition,
the complete data set and all processing details are available from the NODC Joint Archive
for Shipboard ADCP: http://ilikai.soest.hawaii.edu/sadcp. A cruise narrative is included in the
companion Seasoar data report at http://damp.coas.oregonstate.edu/coast/seasoar. This work
was funded by National Science Foundation grant OCE-9907854.
