Impacts of Ocean Waves on the Atmospheric Surface Layer: Simulations and Observations

Abstract

Standard Form 298 (Rev. 8/98) REPORT DOCUMENTATION PAGEPrescribed by ANSI Std. Z39.18 Form Approved OMB No. 0704-0188The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 3. DATES COVERED (From -To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER This this award investigated surface boundary layers and air-sea interaction with theoretical and numerical research. Our long term scientific objective was to explore the nature of intermittency, coherent structures, and turbulent fluxes and their coupling in the surface layers of the marine atmospheric and oceanic planetary boundary layers (PBL). Efforts were focused on the effects of surface gravity waves on the near-surface dynamics, surface fluxes, and coupling between the atmospheric and oceanic PBLs. The final results of this work are provided in 2 journal articles and a reviewed meeting paper. AUTHOR(S) PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S)12Peter Sullivan Abstract. Gravity waves on the sea surface reflect coupling between the atmosphere and ocean. They play important dynamical roles in the transfer of momentum, heat, and scalars, but how they interact with background oceanic (and atmospheric) turbulence is still not well understood. This is especially true under high winds where waves foster Langmuir circulations but also break intermittently.Results from high-resolution large eddy simulations (LESs) that include stochastic breaking waves and the Craik-Leibovich "vortex force" are analyzed. Under certain sea states turbulence (anisotropic seed vorticity) generated by breaking waves initiates Craik-Leibovich instabilities that lead to coherent structures, viz., Langmuir cells and intermittent downwelling jets both of which impact ocean mixing. We suggest a mechanism as to how breaking waves couple with the vortex force that leads to the formation of these flow structures. IntroductionGravity waves at the sea s...