Determination of the deep water arrival direction of ocean swell at a coastal station

Abstract

Three previously unpublished methods for empirically determining deep-water swell direction were examined in this work: triangulation using two widely separated wave sensors, intersection using weather maps and a single wave sensor, and swell point-source estimation from weather maps. The primary objective of each method was to identify a single point source of the swell train produced in an approaching cyclonic storm. Method (1) was not adequately tested, but results as applied to swell from one storm were favorable. Methods (2) and (3), applied to five selected North Pacific storms, gave close agreement on the swell origin time (15 minutes to 6 hours) and source point location (27 to 362 nautical miles), and on swell arrival direction at Monterey, California (0.1 to 5.3 degrees). Methods (1) and (2) give deep-water directions for swell trains that have already arrived, while Method (3) is a prediction method