### Abstract

A 38 kHz vessel-mounted acoustic Doppler current profiler is used to explore in detail the dynamics of an anticyclonic and a cyclonic eddy during two transits of the cruise vessel Explorer of the Seas from the Caribbean to New Jersey in July 2007. The radial scale of the two eddies is similar, but whereas the cyclone is strongly surface intensified, the anticyclone has its maximum expression with near-solid body rotation between 200 and 800 m depth. The anticyclone has a minimum in relative vorticity very close to-f at 800 m depth and the cyclone has a maximum of about +1.6 f close to the surface where f is the local Coriolis parameter. By integrating the momentum equation the geopotential anomaly field and hence the potential energy of the eddies can be determined quite accurately, which means that the kinetic and potential energy of the eddies can be determined purely through acoustic remote sensing. Given a density profile just outside the eddy one can integrate the gradient wind equation to obtain an estimate of the density and hence potential vorticity fields through the two eddies. The acoustic backscatter patterns in the eddies are quite distinct from the surrounding waters. The backscatter intensity of the main scattering layer at ∼600 m depth decreases by ∼10 dB in the core of both eddies. In the cyclonic eddy three identifiable scattering layers in the main thermocline show a strong tendency for the scattering layer to track the shoaling density structure toward the center of the eddy.

Original language | English |
---|---|

Article number | C12017 |

Journal | Journal of Geophysical Research: Oceans |

Volume | 116 |

Issue number | 12 |

DOIs | |

State | Published - Jan 1 2011 |

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### ASJC Scopus subject areas

- Geochemistry and Petrology
- Geophysics
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
- Oceanography

### Cite this

*Journal of Geophysical Research: Oceans*,

*116*(12), [C12017]. https://doi.org/10.1029/2011JC007307

**A tale of two eddies : Diagnosing coherent eddies through acoustic remote sensing.** / Rossby, T.; Flagg, C.; Ortner, P.; Hu, C.

Research output: Contribution to journal › Article

*Journal of Geophysical Research: Oceans*, vol. 116, no. 12, C12017. https://doi.org/10.1029/2011JC007307

}

TY - JOUR

T1 - A tale of two eddies

T2 - Diagnosing coherent eddies through acoustic remote sensing

AU - Rossby, T.

AU - Flagg, C.

AU - Ortner, P.

AU - Hu, C.

PY - 2011/1/1

Y1 - 2011/1/1

N2 - A 38 kHz vessel-mounted acoustic Doppler current profiler is used to explore in detail the dynamics of an anticyclonic and a cyclonic eddy during two transits of the cruise vessel Explorer of the Seas from the Caribbean to New Jersey in July 2007. The radial scale of the two eddies is similar, but whereas the cyclone is strongly surface intensified, the anticyclone has its maximum expression with near-solid body rotation between 200 and 800 m depth. The anticyclone has a minimum in relative vorticity very close to-f at 800 m depth and the cyclone has a maximum of about +1.6 f close to the surface where f is the local Coriolis parameter. By integrating the momentum equation the geopotential anomaly field and hence the potential energy of the eddies can be determined quite accurately, which means that the kinetic and potential energy of the eddies can be determined purely through acoustic remote sensing. Given a density profile just outside the eddy one can integrate the gradient wind equation to obtain an estimate of the density and hence potential vorticity fields through the two eddies. The acoustic backscatter patterns in the eddies are quite distinct from the surrounding waters. The backscatter intensity of the main scattering layer at ∼600 m depth decreases by ∼10 dB in the core of both eddies. In the cyclonic eddy three identifiable scattering layers in the main thermocline show a strong tendency for the scattering layer to track the shoaling density structure toward the center of the eddy.

AB - A 38 kHz vessel-mounted acoustic Doppler current profiler is used to explore in detail the dynamics of an anticyclonic and a cyclonic eddy during two transits of the cruise vessel Explorer of the Seas from the Caribbean to New Jersey in July 2007. The radial scale of the two eddies is similar, but whereas the cyclone is strongly surface intensified, the anticyclone has its maximum expression with near-solid body rotation between 200 and 800 m depth. The anticyclone has a minimum in relative vorticity very close to-f at 800 m depth and the cyclone has a maximum of about +1.6 f close to the surface where f is the local Coriolis parameter. By integrating the momentum equation the geopotential anomaly field and hence the potential energy of the eddies can be determined quite accurately, which means that the kinetic and potential energy of the eddies can be determined purely through acoustic remote sensing. Given a density profile just outside the eddy one can integrate the gradient wind equation to obtain an estimate of the density and hence potential vorticity fields through the two eddies. The acoustic backscatter patterns in the eddies are quite distinct from the surrounding waters. The backscatter intensity of the main scattering layer at ∼600 m depth decreases by ∼10 dB in the core of both eddies. In the cyclonic eddy three identifiable scattering layers in the main thermocline show a strong tendency for the scattering layer to track the shoaling density structure toward the center of the eddy.

UR - http://www.scopus.com/inward/record.url?scp=84055221838&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84055221838&partnerID=8YFLogxK

U2 - 10.1029/2011JC007307

DO - 10.1029/2011JC007307

M3 - Article

VL - 116

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 2169-9275

IS - 12

M1 - C12017

ER -