CAREER: Langmuir Circulation--Internal Wave Interactions

University Of New Hampshire, Durham NH

Investigators

Abstract

0348981 This CAREER project is an integrated program of research and education that will improve our understanding of the oceanic mixed layer, attract students to technical disciplines, and equip such students with critical thinking strategies. The intellectual merit of the research program derives from the formulation and first-principles analysis of simplified ocean models to investigate the role of Langmuir circulation-internal wave interactions in mixed layer-pycnocline coupling. Langmuir circulation is a convective motion, consisting of a system of counter-rotating, roughly wind-aligned vortices, that dominates the observed kinematics of the upper ocean. Recent theoretical, computational and observational evidence suggests that the largest vortices, which rapidly re-distribute mass, momentum and energy throughout the mixed layer, may interact with internal gravity waves propagating in the pycnocline. The remarkable observations of Farmer motivate the process studies and provide high-quality data for model comparisons. A complement of primary and secondary stability studies, asymptotic analyses and two-dimensional numerical simulations will be used to establish whether Langmuir circulation-internal wave coupling can alter mixing and transport within and beneath the surface layer, e.g. by modifying the growth rate or stability of the vortex system, or by increasing small-scale internal-wave activity within the pycnocline. These theoretical studies should provide a useful foundation for future large-eddy simulations and observations of mixed-layer-pycnocline coupling under realistic oceanic conditions. The objectives of the educational program are to provide training for high school science teachers, to encourage students to pursue technical careers and to better enable these students to think critically about fundamental technical concepts by promoting active, integrative learning. These goals will be achieved through an approach largely centered around the theme of Fluid Waves in Technology & the Environment. A host of opportunities will be created for high school, undergraduate and graduate students to participate in project-based learning experiences, including: research in theoretical oceanography, construction and use of hands-on wave demonstrations, and development of analytical-numerical models of nonlinear wave propagation in the versatile computing environment MATLAB. Additional pedagogical reforms, including the use of regular concept quizzes and writing assignments, will be implemented in the thermal-fluids courses taught by the principal investigator. The broader impacts of this CAREER development plan include its potential: to improve mixed-layer parameterizations used in numerical modeling of weather, climate, biological processes and pollutant dispersal; to foster networks among theoretical, computational and observational oceanographers; to provide training for undergraduate and graduate students in theoretical oceanography; to provide authentic science experiences for high school students through teacher training; to incorporate improvements in pedagogy into the classroom; and to provide a firm foundation for the principal investigator to make a lifetime of integrated contributions to teaching and research.