On the Formation of Whitecaps by a Threshold Mechanism. Part III: Field Experiment and Comparison with Theory

Abstract This paper is the third in a series of papers which seek to evaluate the hypothesis that deep water whitecapping is predictable in terms of a threshold mechanism involving the vertical acceleration. Parts I and II of the series have developed the descriptive framework for the investigation and examined several geometro-statistical predictions of the threshold model, the first by direct integration of the joint probability densities for the vertical acceleration, the second by Monte Carlo simulation of the vertical acceleration field. In Part III we describe a field experiment designed to study the statistical geometry of the whitecap field and to test the theoretical predictions of Parts I and II. This experiment, conducted at an experimental site in the Bight of Abaco, Bahamas, combines a series of photographs of whitecap events with simultaneous array measurements of waves. The photographs were taken from above the water surface and cover an area nominally 10 m on a side. A total of 2292 whitec...