Abstract: Abstract Field observations reveal that waves propagating onto a beach from deeper water have a grouped structure. Associated with this pattern of alternating high and low waves is a long wave forced by radiation stress variations due to the changing short wave height. As the wave groups propagate onshore, the relationship between the variation in the short wave height and the long wave motion is complicated by breaking of the short waves, reflection of the long wave and the generation of a free long wave by time variation of the breakpoint pos...
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