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AGU: Journal of Geophysical Research, Oceans

 

Keywords

  • Yucatan Channel
  • EOFs
  • frontal meanders

Index Terms

  • Oceanography: Physical: Western boundary currents
  • Oceanography: General: Continental shelf processes
  • Oceanography: General: Numerical modeling
Abstract
Cited By (2)
 

Abstract

Modeled and observed empirical orthogonal functions of currents in the Yucatan Channel, Gulf of Mexico

Lie-Yauw Oey

Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, New Jersey, USA

Tal Ezer

Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, New Jersey, USA

Wilton Sturges

Department of Oceanography, Florida State University, Tallahassee, Florida, USA

Candela et al. [2003] have reported empirical orthogonal function (EOF) analyses based on 23-month current-meter and acoustic Doppler current profiler measurements in the Yucatan Channel. Those authors noted the difference between EOFs obtained from observations and their z-level models and EOFs calculated by Ezer et al. [2003] from the results of a terrain-following model. Here a new analysis is reported that explains this difference, and that also suggests the importance of shelf-edge meander mode of the core Loop Current in the channel. We show that the terrain-following model gives EOFs with characteristics similar to those observed when data from the upper slope and shelf in the western portion of the model channel are omitted. Modes 1 and 2 have tripole and dipole structures with energies (35%, 26%), respectively, of total energy, and correlate with “slow” vacillation of the core-current for periods >50 days. Exclusion of upper-slope and shelf data eliminates a short-period and energetic component inherent in Ezer et al.'s original mode 1 EOF. This mode correlates with frontal meanders of the core current over the shelf edge in the western portion of the channel. The short-period mode may be missing or underestimated in observational and z-level models' analyses, since there were only a few moorings over the upper slope and shelf, and z-level models have step-like topography with generally lower resolution in shallower seas.

Received 24 February 2004; accepted 23 June 2004; published 14 August 2004.

Citation: Oey, L.-Y., T. Ezer, and W. Sturges (2004), Modeled and observed empirical orthogonal functions of currents in the Yucatan Channel, Gulf of Mexico, J. Geophys. Res., 109, C08011, doi:10.1029/2004JC002345.

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