1. LT John Marburger OC 3570 March 17, 2004
An Investigation Into Spatial Variation of the Deep Sound Channel Off the Central California Coast
LT John Marburger
OC 3570
March 17, 2004

2. Overview
Background/Project Goals
Data
Methods
Results
Conclusions

3. Background/Goals
METOC focus is shifting to near shore/littoral environment
Data readily available
Some initial prior research performed
Project has Navy relevance
Characterization of spatial and temporal variation of sound velocity provides a stable foundation to build on information superiority.

4. Data
Lots of CTD data!!
Positional data

5. Line 67

6. Data Analysis Methods Convert CTD data
Conductivity to Salinity
Pressure into depth
MATLAB code did above conversions and simultaneously made a SVP for each station within a given data set

7. Data Analysis Methods
SVP axis truncated to focus in on Deep sound channel axis ( meters)
Scaling factor for waterfall plots

8. Data Analysis Methods SVP’s contained high frequency noise
Butterworth filter
Filtering coefficients will vary.
Sound reacts to variations based on its frequency
Done by inspection

9. Data Analysis Methods
Sound speed minimum gathered for each SVP.

10. Data Analysis Methods
Each sound speed minimum was plotted versus longitude.
Longitude
was binned
and averaged

11. Results

12. Results
Monthly analysis performed
El Nino year analysis performed

13. February trend

14. July trend

15. El Nino trend

16. Conclusions
A statistically significant shoaling of the deep sound channel is observed along Line 67.
Monthly/seasonal investigations yielded limited results due to limited data
The anomalous El Nino year produced little change in deep sound channel axis depth compared to the ensemble

17. Further study Dynamics of the trend?
Davidson/California currents?
Does the trend persist north and south?