Introduction to the CDIP Monitoring and Prediction (MOP) System

The Coastal Data Information Program (CDIP) is a research group at Scripps Institution of Oceanography that monitors coastal waves and nearshore sand levels on regional scales. The mission of the program is to improve our basic understanding of, and ability to predict, coastal waves and shoreline change.

In California, CDIP maintains a network of optimally-placed, directional wave buoys from San Diego to Eureka. The buoy measurements are used to initialize a high spatial resolution (100m x 100m) linear spectral wave propagation model, which accounts for island blocking, refraction and shoaling. The resulting hourly hindcasts and nowcasts of CA coastal wave conditions have a level of accuracy that is not possible with more traditional wind-wave generation models that are initialized with modeled wind fields.

CDIP provides public access to its monitoring-based wave predictions via the CDIP MOnitoring and Prediction (MOP) System. Three types of wave research products are available:

  • MOP Regional Swell Predictions (waves with periods 8 seconds and longer), which cover the the outer waters of the continental shelf and the Southern California Bight.

  • MOP Inner Waters Sea & Swell Predictions (wave periods from 2-30 seconds) which cover the waters within ~10 kilometers (6 miles) of the mainland coast. This information is primarily used to support marine safety around harbors and along popular boating routes.

  • MOP Alongshore Sea & Swell Predictions (wave periods from 2-30 seconds) in 10m (33ft) water depth with ~100m alongshore spacing in Southern California, and 15m (50ft) water depth with ~200m alongshore spacing north of Point Conception.

  • The alongshore wave predictions are being used in combination with sand level measurements in San Diego County to develop more robust data-adaptive methods for real-time hazard mitigation, regional sediment management (RSM), and long-range shoreline change predictions.

    The alongshore MOPs are identified by CA county and numbered from south (downcoast) to north (upcoast). To access model predictions please contact CDIP,

    MOP System Approach

  • Linear Model: each frequency modeled independently.
  • Use offshore buoys to predict swell (f=0.04-0.09Hz).
  • Use local buoys to predict seas (f=0.09-0.25Hz).
  • Weight buoy directional spectra by distance from prediction site.

  • MOP System Modeling Steps

    For Each Wave Frequency Band:

  • Define 100% open direction range for each offshore buoy location [ Swell/Offshore Buoys Only].
  • Smooth buoy data over 3-hour window.
  • Estimate directional spectra (MEM).
  • Lag time series of deep water directional spectra to the prediction site for 100% open direction range using group velocity (assume deep water everywhere and no islands at this stage).
  • Combine lagged directional spectra & weight by distance between buoy and prediction site.
  • Transform weighted & lagged deep water directional spectra to sheltered wave energy and directional moments (spectral refraction transformation coefficients).

  • References

    The California coastal wave monitoring and prediction system W. C. O'Reilly et al.
    Coastal Eng., v116, Oct. 2016, pp118-132.

    Wave Monitoring in The Southern California Bight. W. C. O'Reilly, R. J. Seymour, R. T. Guza, D. Castel,
    Ocean Wave Measurement and Analysis, Proc. 2nd Int. Symp., July 25-28, 1993, pp448-457.

    Comparison of Two Spectral Wave Models in the Southern California Bight. W. C. O'Reilly and R. T. Guza,
    Coastal Eng., v19, pp263-282, 1993.