Accession Number : ADA113385

Title :   Wave Directional Characteristics on a Partially Sheltered Coast.

Descriptive Note : Doctoral thesis,


Personal Author(s) : Pawka,Steven Sitter

PDF Url : ADA113385

Report Date : Jan 1982

Pagination or Media Count : 279

Abstract : The sheltering effects of the Channel Islands on the wind generated surface gravity wave field at the Southern California coastline are studied with an extensive field experiment. Emphasis is placed on wave directional measurements sampled at Torrey Pines Beach with a linear array of pressure sensors. A linear model was implemented for the evaluation of wave transformations around the islands due to refraction over the shoals in the island region and blocking due to the island cross-sections. This model shows a strong influence of refraction on waves with frequencies less than 0.10 Hz. Only limited confirmation of the model in the frequency range 0.08-0.11 Hz is obtained due to the variable quality of the deep ocean estimates of wave directionality. Several estimation techniques were compared for their performance in directional spectrum analysis. Two methods developed here show significant improvement over the Maximum Likelihood Estimator in defining spectral gaps and in the partition of energy among spectral peaks. The estimation problem of extracting accurate estimates of the onshore flux of longshore directed momentum, Syx, from linear array data is addressed. A window shaping technique is developed and compared to the integration of the directional spectrum estimates. Using field data, the linear array methods are compared with a biaxial current meter and a 'slope' array.

Descriptors :   *Ocean waves, Directional, North Pacific Ocean, California, Coastal regions, Santa Barbara Islands, Wave propagation, Refraction, Frequency, Spectra, Statistical analysis, Theses

Subject Categories : Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE