1. OPERATIONAL OCEANOGRAPHY
How Wave Spectra vary over time at two locations in response to wind forcing
LT Carlos Fernandes

2. Outliner: 1. Proposal 2. Data and Methods
3. CDIP – Coastal Data Information
Program
4. Bulk Parameters
5. Spectra Analysis
6. Conclusions

3. Proposal: 1. Compare wave data between:
a) National Data Buoy Center
b) NPS Datawell Waverider buoy
c) Ship observations by students
d) Wind data from 46042
e) Wind data from Monterey Bay Aquarium
f) CDIP model for wave forecast

4. Data and Methods: 1. Ship track 2. NDBC buoy – 46042 depth: 2000m
3. NPS Waverider
depth: 100m
6. WINDS from M.B.Aquarium
4. Ship observations
5. CDIP – Model predictions

5. Data and Methods: 1920m depth Anemometer Barometer Temperature
Directional
100m depth
Temperature
Directional
Dist: 42 Km
Az= 098

6. CDIP:
The Coastal Data Information Program (CDIP) is an extensive network for monitoring
waves along the coastlines of the United States, with a strong emphasis on Pacific coast
Initiated in 1975
Operated by the Ocean Engineering Research Group (OERG) at Scripps Institution
of Oceanography (SIO).
CDIP began to collect directional wave data using arrays of underwater
pressure sensors
Non-directional buoys came into use collecting data further offshore
In the 1990s CDIP first began to use directional buoys
The program started to make its data available in real-time over the internet

7. CDIP: CDIP models: 1. Forecast Models 2. Nowcast Models
a) Regional Models
- Refraction-diffraction model
b) Local Models
c) Sea and Swell Models
Regional models
Wave height maps generated from offshore buoy readings.
The maps only include swell with a period of 8 seconds or greater.
local wind seas are not modeled.

8. Bulk Parameters (Waves):
Green – days where the ship were close to buoy
Blue – days where the ship were close to NPS buoy

9. Bulk Parameters (Wind):

10. Spectra Analysis (NDBC):

11. Spectra Analysis (NPS):

12. Spectra Analysis (CDIP):

13. Spectra Analysis:

14. Spectra Analysis:

15. Spectra Analysis:

16. Comparison with CDIP

17. Conclusions Primary Swell around 10s from WNW – more energetic
Secondary Swell between 15 and 20s from SSW
less energetic
Sea breeze - ±24H period – always present
How important is a spectral analysis.
Having waves from different directions
Having waves with different periods
Important for planning missions
What weapons?
What platform?

18. Conclusions Overall, good agreement between CDIP and measurements
Comparison between and NPS buoys showed that
there is a significant refraction in the area (not new) as a
significant energy dissipation
Comparisons showed that CDIP over predicts peaks energy
although at the right time
Ship observations: Could be better!

19. References “A Comparison of two spectral wave models in the Southern
California Bight”, O’Reilly and Guza, Coastal Eng., 1993,
v19, p