Aanderaa DCM 12 Doppler current meter performance characteristics

Field test were performed on a new Aanderaa DCM 12 Doppler current meter by comparing its performance with an RD Instruments 1200 kHz acoustic Doppler current profiler (ADCP). Aanderaa instruments provided the DCM 12 and furnished support to assure that the DCM 12 was deployed and operated properly. The comparison site selected was the Old Port Tampa ADCP station of the Tampa Bay Physical Oceanographic Real Time System (PORTS), Tampa Bay, Florida. This site has been occupied by a bottom mounted 1200 kHz ADCP for over 3 years and the flow regime is well defined and homogeneous. The ADCP is located in 12 meters of water sad provides current profile data in real time every 6 minutes. The DCM 12 was placed on the bottom within 50 meters of the ADCP and internally recorded data over a 2 hour period during a peak ebb current of approximately 60 cm/s. A second test was conducted over a 6 hour period from a flood current of 30 cm/s to a peak ebb current or 70 cm/s. Data indicate relatively good agreement In speed over a 2 hour averaging interval. Individual 6 minute ensemble comparisons show considerable noise in the DCM 12 data. Test results also indicate acoustic beam side lobe effects on both systems in the near surface layer.