1. Turbidity in Monterey Bay: Operational Oceanography Winter 2009 Project
Rip Coke
16MAR09

2. Outline Motivation MIW Threat Area Equipment Data Set
Analysis and Calculations
Conclusions
References

3. Driving Force MIW Thesis
Importance of turbidity in detection and classification operations
Dive Operations
RMV Maneuvering
MP Placement

4. Adapted by Nicky Wheatley from NRC: Oceanography for Mine Warfare
MIW Threat
Various degrees of mine threats (depth depending)
0-25m is a critical zone
Surf Zone
0 – 3m
Obstacles
Anti Invasion
Bottom
Moored
Drifting
Shallow Water
12 – 60m
Moored (Rising)
Very Shallow Water
3 – 12m
Deep Water > 60m
Adapted by Nicky Wheatley from NRC: Oceanography for Mine Warfare

5. Acoustic Doppler Current Profiler (ADCP)
Primary tool for measuring the sub-surface current:
- Low frequency – penetrates further down into the water column
- Uses Doppler shift to determine speed and direction of scattering particles in the water column

6. MBARI Vertical Profiler (MVP)
The MBARI Vertical Profiler combines the high-resolution data of a profiler with the long-term capability of a mooring for monitoring variations at the upwelling fronts
Profiler was designed to sit at the bottom of the mooring tether and ascend, sampling a vertical profile every hour

7. Data Set and Collection Location
ADCP (13SEP-27SEP)
Time
Pressure
Depth (3m-26m)
U Velocity
V Velocity
MVP (31AUG-27SEP)
Depth (0-15m)
Temperature
Salinity
Chlorophyll
Optical Backscatter
ADCP
MVP

8. Temperature and Salinity Profiles

9. Chlorophyll and Optical Backscatter

10. U and V Velocity

11. Rotated ADCP Velocity Data
Non Rotated
Rotated (15o)

12. East/West Velocity (Along Shore)

13. North/South Velocity (Cross Shore)

14. Empirical Orthogonal Function (EOF)
EOF analysis is a decomposition of a signal or data set in terms of orthogonal basis functions which are determined from the data
EOF method finds both time series and spatial patterns
The basis functions are chosen to be different from each other accounting for as much variance as possible.

19. East
West

20. East
West

21. North
South

22. North
South

23. Calculations Richardson Number
A dimensionless number expressing the ratio of the removal of energy by buoyancy forces to its production by the shear in a flow.
overall parameter describing a whole flow as opposed to the gradient and flux
The critical Richardson number: Rc = 0.25
Ri < Rc = Unstable
Ri > Rc = Stable
Brunt-Vaisala Frequency
ρ is the potential density and depends on both temperature and salinity

24. Density Profile

25. Velocity Profile

26. Temporal Smoothing

28. Richardson Number (Not Log)

29. Richardson Number (Log)

30. Met Check Date Wind m/s Wave Ht m 15SEP 005/4 999 16SEP 338/6.3 1.21
19SEP /8 (gst 11)
20SEP /3
21SEP /4
Wave Ht m
999
1.21
2.05
2.57
3.07
2.07
2.04
Info provided by NOAA buoy SEPT 1200

31. Graph provided by John Ryan

32. Graph provided by John Ryan

33. Conclusions Limited scope data
Depths not compatible and restrictive of bottom interpretation for turbidity and sediment movement
Sampling rates varied but could be overcome by data massaging
Data compatible for buoyancy, shear and Richardson Number calculations
Instabilities exist where upwelling is present
Instability (upwelling) consist with measured increase in surface winds and wave height

34. Questions?

35. References Prof Collins Dr John Ryan, MBARI Wikipedia
NOAA Marine Environmental Buoy Database
Tarry Rago
Tetyana Margolina