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Caitlin Whalen

Senior Oceanographer

Affiliate Assistant Professor, Oceanography

Email

cwhalen@apl.uw.edu

Phone

206-897-1739

Research Interests

Small-scale oceanic processes as viewed from global and regional scales including diapycnal mixing, internal waves, submesoscale dynamics, air–sea interactions, and mesoscale–internal wave interactions

Education

B.A. Physics, Reed College, 2008

Ph.D. Physical Oceanography, University of California at San Diego, 2015

Publications

2000-present and while at APL-UW

Direct observations of near-inertial wave ζ-refraction in a dipole vortex

Thomas, L.N., L. Rainville, O. Asselin, W.R. Young, J. Girton, C.B. Whalen, L. Centurioni, and V. Hormann, "Direct observations of near-inertial wave ζ-refraction in a dipole vortex," Geophys. Res. Lett., 47, doi:10.1029/2020GL090375, 2020.

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16 Nov 2020

Generated at large horizontal scales by winds, near‐inertial waves (NIWs) are inefficient at radiating energy without a shift to smaller wavelengths. The lateral scales of NIWs can be reduced by gradients in the Coriolis parameter (β‐refraction) or in the vertical vorticity (ζ‐refraction) or by strain. Here we present ship‐based surveys of NIWs in a dipole vortex in the Iceland Basin that show, for the first time, direct evidence of ζ‐refraction. Differences in NIW phase across the dipole were observed to grow in time, generating a lateral wavelength that shrank at a rate consistent with ζ‐refraction, reaching ~40 km in 1.5 days. Two days later, a NIW beam with an ~13 km horizontal and ~200 m vertical wavelength was detected at depth radiating energy downward and toward the dipole's anticyclone. Strain, while significant in strength in the dipole, had little direct effect on the NIWs.

Internal wave-driven mixing: Governing processes and consequences for climate

Whalen, C.B., C. de Lavergne, A.C. Naveira Garabato, J.M. Klymak, J.A. MacKinnon, and K.L. Sheen, "Internal wave-driven mixing: Governing processes and consequences for climate," Nat. Rev. Earth Environ., 1, 606-621, doi:10.1038/s43017-020-0097-z, 2020.

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13 Oct 2020

Turbulent mixing from breaking oceanic internal waves drives a vertical transport of water, heat and other climatically important tracers in the ocean, thereby playing an important role in shaping the circulation and distributions of heat and carbon within the climate system. However, linking internal wave-driven mixing to its impacts on climate poses a formidable challenge, since it requires understanding of the complex life cycle of internal waves — including generation, propagation and breaking into turbulence — and knowledge of the spatio-temporal variability of these processes in the diverse, rapidly evolving oceanic environment. In this Review, we trace the energy pathways from tides, winds and geostrophic currents to internal wave mixing, connecting this mixing with the global climate system. Additionally, we discuss avenues for future work, including understanding energy transfer processes within the internal wave field, how internal waves can be modified by background currents and how internal wave mixing is integrated within the global climate system.

A parameterization of local and remote tidal mixing

de Lavergne, C., and 9 others including C.B. Whalen, "A parameterization of local and remote tidal mixing," J. Adv. Model. Earth Syst., 12, e2020MS002065, doi:10.1029/2020MS002065, 2020.

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1 May 2020

Vertical mixing is often regarded as the Achilles' heel of ocean models. In particular, few models include a comprehensive and energy‐constrained parameterization of mixing by internal ocean tides. Here, we present an energy‐conserving mixing scheme which accounts for the local breaking of high‐mode internal tides and the distant dissipation of low‐mode internal tides. The scheme relies on four static two‐dimensional maps of internal tide dissipation, constructed using mode‐by‐mode Lagrangian tracking of energy beams from sources to sinks. Each map is associated with a distinct dissipative process and a corresponding vertical structure. Applied to an observational climatology of stratification, the scheme produces a global three‐dimensional map of dissipation which compares well with available microstructure observations and with upper‐ocean finestructure mixing estimates. This relative agreement, both in magnitude and spatial structure across ocean basins, suggests that internal tides underpin most of observed dissipation in the ocean interior at the global scale. The proposed parameterization is therefore expected to improve understanding, mapping, and modeling of ocean mixing.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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