1. Moorings and Current Meters Ellen Martinsek EPS 131 December 14, 2005

2. Outline Moorings –Purpose –Deployment & Recovery –Specific Projects Current Meters –Different Methods of Measuring Current –Acoustic Doppler Measurements –Applications

3. Moorings Connection between water surface and instrumentation in the ocean below the surface

4. Deployment & Recovery Difficult since the mooring cable breaks if moved too quickly Need to keep instruments and data safe

5. Back to WHOI Sub-Surface Mooring Operations Group: over 90% instrument and data recovery

6. North Pole Environmental Observatory Retrieving a mooring that has been collecting oceanographic data from the Arctic Ocean for a year at the NSF’s North Pole Environmental Observatory Photo Credit: Peter West/National Science Foundation First year-round mooring at the North Pole retrieved in April 2002 Purpose: to see how the Arctic Ocean influences global climate

7. Monterey Ocean Observing System (MOOS) test mooring

8. MOOS test mooring instruments “S” bend float Power source (on float) Biggest engineering problem: creating a cable that can stay intact! 11 days after the first deployment (December 3, 2002) the cable snapped  had to redesign it before finally redeploying on April 23, 2004.

9. Measuring Current … Mechanical current meters Electromagnetic current meters Acoustic Travel Time current meters Acoustic Doppler measurements

10. Why sound is good to use The Doppler Effect Back Scatter Sonar – How It Works

11. Acoustic Doppler Current Profiler (ADCP) RDCP 600 (by Aanderaa) – 600kHz self-recording Doppler Current Profiler Constant frequency pings transmitted Ricochet off suspended particles and reflect back Calculate speed of particle and surrounding water using Doppler shift

12. Applications of Current Profiling Climatic Research Ports and Harbors Fish Farming Pollution Control

13. Summary Moorings serve as a connection between the water surface (which itself is connected via satellite to labs onshore) and instruments in the ocean An important example of such instrumentation is the current profiler; in particular, the ADCP

14. References http://www.pmel.noaa.gov/vents/nemo1999/logbook/cal062399/ http://www.mbari.org/news/homepage/2004/moosII.html http://www.whoi.edu/institutes/occi/currenttopics/ct_oms_stationw.ht mlhttp://www.whoi.edu/institutes/occi/currenttopics/ct_oms_stationw.ht ml http://www.washington.edu/newsroom/news/2002archive/05- 02archive/npfactsheet.htmlhttp://www.washington.edu/newsroom/news/2002archive/05- 02archive/npfactsheet.html http://www.antarctica.ac.uk/BAS_Science/programmes2000- 2005/DYNAMOE/Moorings/index.htmlhttp://www.antarctica.ac.uk/BAS_Science/programmes2000- 2005/DYNAMOE/Moorings/index.html http://walrus.wr.usgs.gov/mcgaw/depmoor.html http://pulson.seos.uvic.ca/lecture.html http://www.soc.soton.ac.uk/OED/gxg/Single_Point_CMs.pdf http://www.aanderaa.com/docs/RDCP_600_D343.pdf http://www.nsf.gov/od/lpa/news/03/ma0329.htm