Wave breaking in developing and mature seas

In response to the growing need for robust validation data for Phillips (1985) breaking wave spectral framework, we contribute new field results observed from R/P FLIP for the breaking crest length distributions, Λ, during two different wind‐wave conditions, and breaking strength during one wind‐wave condition. The first experiment in Santa Barbara Channel had developing seas and the second experiment in the central Pacific Ocean south of Hawaii had mature seas. These are among the first experiments to use dissipation rate measurements probing up into the breaking crest together with simultaneous measurements of breaking crest length distributions. We directly measured the effective breaking strength parameter to be 4.2(±1.8)×10−5 in mature seas with wave age, cp/u*, of 40–47. We also found that the velocity scale of the breaking dissipation rate peak decreases with increasing wave age. Further, the breaking crest length spectrum falls off slower than the c−6 behavior predicted by Phillips (1985). The integrated dissipation rate was consistently higher for mature seas compared to developing seas due to higher energy and momentum fluxes from the wind. Key Points Velocity scale of breaking dissipation peak decreases with increasing wave age Breaking spectrum falls off slower than predicted by Phillips (1985) framework Breaking strength of 4.2 (+/− 1.8) x 10−5 for mature seas was directly measured