### Abstract

Internal gravity waves that are generated in the open ocean have a universal frequency spectrum, called Garrett–Munk spectrum. By initializing internal waves that satisfy the Garrett–Munk spectrum in a non-hydrostatic numerical model, we investigate the material dispersion produced by these internal waves. Three numerical experiments are designed: Exp.-1 uses a linearly stratified fluid, Exp.-2 has an upper mixed layer, and Exp.-3 incorporates a circular front into the upper mixed layer. Resorting to neutrally buoyant particles, we investigate the dispersion in terms of metrics of the relative dispersion and finite-scale Lyapunov exponent (FSLE). Exp.-1 shows that the dispersion regime produced by these internal waves is between ballistic and diffusive based on relative dispersion, and is however ballistic according to FSLE. The maximum FSLE at scales of 100 m is about 5 day(Formula presented.), which is comparable to that calculated using ocean drifters. Exp.-2 demonstrates that internal waves can generate flows and material dispersion in an upper mixed layer. However, when mixed layer eddies are present, as in Exp.-3, the dispersion in the mixed layer is controlled by the eddies. In addition, we show that inertial oscillations do not affect the relative dispersion, but impact FSLE at scales of inertial oscillations.

Original language | English (US) |
---|---|

Pages (from-to) | 1-23 |

Number of pages | 23 |

Journal | Environmental Fluid Mechanics |

DOIs | |

State | Accepted/In press - Nov 16 2016 |

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### Keywords

- Finite-scale Lyapunov exponent (FSLE)
- Garrett–Munk spectrum
- Inertial oscillation
- Relative dispersion

### ASJC Scopus subject areas

- Environmental Chemistry
- Water Science and Technology

### Cite this

*Environmental Fluid Mechanics*, 1-23. https://doi.org/10.1007/s10652-016-9491-y

**Material dispersion by oceanic internal waves.** / Wang, Peng; Ozgokmen, Tamay M; Haza, Angelique C.

Research output: Contribution to journal › Article

*Environmental Fluid Mechanics*, pp. 1-23. https://doi.org/10.1007/s10652-016-9491-y

}

TY - JOUR

T1 - Material dispersion by oceanic internal waves

AU - Wang, Peng

AU - Ozgokmen, Tamay M

AU - Haza, Angelique C.

PY - 2016/11/16

Y1 - 2016/11/16

N2 - Internal gravity waves that are generated in the open ocean have a universal frequency spectrum, called Garrett–Munk spectrum. By initializing internal waves that satisfy the Garrett–Munk spectrum in a non-hydrostatic numerical model, we investigate the material dispersion produced by these internal waves. Three numerical experiments are designed: Exp.-1 uses a linearly stratified fluid, Exp.-2 has an upper mixed layer, and Exp.-3 incorporates a circular front into the upper mixed layer. Resorting to neutrally buoyant particles, we investigate the dispersion in terms of metrics of the relative dispersion and finite-scale Lyapunov exponent (FSLE). Exp.-1 shows that the dispersion regime produced by these internal waves is between ballistic and diffusive based on relative dispersion, and is however ballistic according to FSLE. The maximum FSLE at scales of 100 m is about 5 day(Formula presented.), which is comparable to that calculated using ocean drifters. Exp.-2 demonstrates that internal waves can generate flows and material dispersion in an upper mixed layer. However, when mixed layer eddies are present, as in Exp.-3, the dispersion in the mixed layer is controlled by the eddies. In addition, we show that inertial oscillations do not affect the relative dispersion, but impact FSLE at scales of inertial oscillations.

AB - Internal gravity waves that are generated in the open ocean have a universal frequency spectrum, called Garrett–Munk spectrum. By initializing internal waves that satisfy the Garrett–Munk spectrum in a non-hydrostatic numerical model, we investigate the material dispersion produced by these internal waves. Three numerical experiments are designed: Exp.-1 uses a linearly stratified fluid, Exp.-2 has an upper mixed layer, and Exp.-3 incorporates a circular front into the upper mixed layer. Resorting to neutrally buoyant particles, we investigate the dispersion in terms of metrics of the relative dispersion and finite-scale Lyapunov exponent (FSLE). Exp.-1 shows that the dispersion regime produced by these internal waves is between ballistic and diffusive based on relative dispersion, and is however ballistic according to FSLE. The maximum FSLE at scales of 100 m is about 5 day(Formula presented.), which is comparable to that calculated using ocean drifters. Exp.-2 demonstrates that internal waves can generate flows and material dispersion in an upper mixed layer. However, when mixed layer eddies are present, as in Exp.-3, the dispersion in the mixed layer is controlled by the eddies. In addition, we show that inertial oscillations do not affect the relative dispersion, but impact FSLE at scales of inertial oscillations.

KW - Finite-scale Lyapunov exponent (FSLE)

KW - Garrett–Munk spectrum

KW - Inertial oscillation

KW - Relative dispersion

UR - http://www.scopus.com/inward/record.url?scp=84995489571&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84995489571&partnerID=8YFLogxK

U2 - 10.1007/s10652-016-9491-y

DO - 10.1007/s10652-016-9491-y

M3 - Article

AN - SCOPUS:84995489571

SP - 1

EP - 23

JO - Environmental Fluid Mechanics

JF - Environmental Fluid Mechanics

SN - 1567-7419

ER -