Whitecap Coverage Dependence on Wind and Wave Statistics as Observed during SO GasEx and HiWinGS ...

• Main Authors: Brumer, Sophia Eleonora, Zappa, Christopher J., Brooks, Ian M., Tamura, Hitoshi, Brown, Scott, Blomquist, Byron W., Fairall, Christopher W., Cifuentes-Lorenzen, Alejandro
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Columbia University 2017
• Subjects: Oceanography; FOS: Earth and related environmental sciences; Ocean-atmosphere interaction; Ocean waves; Ocean waves > Mathematical models; Southern Ocean
• Online Access: https://dx.doi.org/10.7916/d88k8kxj; https://academiccommons.columbia.edu/doi/10.7916/D88K8KXJ

Concurrent wavefield and turbulent flux measurements acquired during the Southern Ocean (SO) Gas Exchange (GasEx) and the High Wind Speed Gas Exchange Study (HiWinGS) projects permit evaluation of the dependence of the whitecap coverage W on wind speed, wave age, wave steepness, mean square slope, and wind-wave and breaking Reynolds numbers. The W was determined from over 600 high-frequency visible imagery recordings of 20 min each. Wave statistics were computed from in situ and remotely sensed data as well as from a WAVEWATCH III hindcast. The first shipborne estimates of W under sustained 10-m neutral wind speeds U10N of 25 m s−1 were obtained during HiWinGS. These measurements suggest that W levels off at high wind speed, not exceeding 10% when averaged over 20 min. Combining wind speed and wave height in the form of the wind-wave Reynolds number resulted in closely agreeing models for both datasets, individually and combined. These are also in good agreement with two previous studies. When expressing W ...