Hindcasting Swell from the Southern Ocean Along the U.S. Pacific Coast.

• Main Authors: Hubertz, J. M., Payne, J. B., Farrar, P. D.
• Other Authors: ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
• Format: Text
• Language: English
• Published: 1995
• Subjects: Physical and Dynamic Oceanography; *FORECASTING; *SEA STATES; WIND; SEASONAL VARIATIONS; CALIFORNIA; PACIFIC OCEAN; HINDCASTING; WISWAVE 2.0 COMPUTER PROGRAM; Pacific; Southern Ocean
• Online Access: http://www.dtic.mil/docs/citations/ADA294220; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA294220

It is well documented that ocean swell arrives at the U.S. Pacific coast especially southern California, from the Southern Ocean during the Northern Hemisphere summer. This swell can have a major impact on sand transport in the littoral zone as it shoals and breaks on the beach. Hindcast wave information for this region does not contain this component of the wave climate. This report describes a method by which this swell can be included in future wave hindcasts. Buoy wave measurements are analyzed to identify and characterize swell from the Southern Hemisphere. The Wave Information Study wave model WISWAVE 2.0 is used to hindcast swell from a hypothetical storm in the Southern Hemisphere as well as actual storms during the summers of 1988 and 1989. Hindcast results are compared to theory and measurements. Swell heights calculated by the model tend to be higher than those determined from measurements. Differences are attributed to loss of swell energy during propagation through the south Pacific islands not represented in the model and possibly to inaccurate wind speeds and directions over the Southern Ocean. Despite differences, the approach is considered practical if model results are calibrated to measurements.