1. UNDERWATER CURRENTS OF THE COAST OF SAN DIEGO, CA
by David Colbert
Special thanks to
Professor Curtis Collins
and the crew of
RV New Horizon

2. OUTLINE Abstract Platform Collection Device Data Collected
Description
Date
Ships Company
Collection Device
Data Collected
Observations
Conclusions
Questions

3. ABSTRACT
The purpose of this research project is to determine the undersea currents of the San Nicholas Basin southwest of Santa Catalina Island and San Clemente Island. This study was conducted from the RV New Horizon using a hull mounted RDI Broadband ADCP.

4. RV NEW HORIZON
170-foot oceanographic research vessel owned by UCSD and run by Scripps Institution of Oceanography. For the NPS, Operational Oceanography and Meteorology cruise summer 2009, there were:
12 crew
8 Oceanographer/Meteorologist
8 Students.
The ship departed Scripps
Pier San Diego, CA
24, July
and returned
28, July 2009
All crew, Oceanographers,
students, and most
Meteorologists returned.

5. RDI BROADBAND ADCP
The ADCP (Acoustic Doppler Current Profiler) uses the Doppler shift to measure current speed and direction. It does this by sending a burst of sound into the water column then measuring the echo of suspended particles carried by the currents as they pass multiple receptor cells. Echoes that are retrieved later are given as deeper recordings.
The ADCP Operation:
Frequency (kHz)
Wavelength 20mm
Transducer diameter 280mm
Beam width at -3dB degrees
Avg. Side lobe level 36dB

6. COLLECTED DATA SST compared to ADCP:
ADCP appears slightly behind the SST
data. This indicates that the ADCP is
off the time sink.

7. LOCAL SURFACE CURRENTS
Circulation Patterns in the Southern California Bight

8. Average 50-100 m depth currents collected by the onboard ADCP
COLLECTED DATA
Average m depth currents collected by the onboard ADCP
Santa Catalina
San Nicholas
San
Diego
San Clemente
San Nicholas Basin

9. OBSERVATION Average 50-100 m Currents Predominant Current
found in the Basin
San Nicholas Basin

10. CONCLUSION
Data collected using the RDI Broadband ADCP, indicates a strong current exists at a depth of m below the surface in the San Nicholas Basin.
Current flows to the north-northwest.
Peak flow occurs southwest of San Clemente Island along the northeast side of the San Nicholas Basin, at roughly 40 cm/sec.

11. QUESTIONS ?