Surface drifter pair spreading in the North Atlantic

Lumpkin, Rick; Elipot, Shane. 2010 Surface drifter pair spreading in the North Atlantic. Journal of Geophysical Research, 115, C12017. 20, pp. https://doi.org/10.1029/2010JC006338

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Abstract/Summary

This study examines spreading of surface drifter pairs deployed as part of the CLIVAR Mode Water Dynamic Experiment (CLIMODE) project in the Gulf Stream region. The spreading is resolved at hourly resolution and quantified by relative dispersion and finite-scale Lyapunov exponents. At scales from 1-3 km to 300-500 km, the dispersion follows Richardson's law, indicating stirring by eddies comparable in scale to the pair separation distance. At larger scales, the spreading becomes a random walk described by a constant diffusivity. The behavior from 1-3 km to the local deformation radius is inconsistent with the enstrophy cascade of 2-D quasigeostrophic turbulence. To test various hypotheses for this result, drifter pair spreading is examined for pairs that were not launched together, pairs deployed in the eastern subtropical North Atlantic, and CLIMODE pairs subsampled to daily temporal resolution. Our results indicate the presence of significant energy at the submesoscale in the Gulf Stream region which flattens the wave number spectrum and dominates surface stirring at this scale range. Results in the less energetic subtropical eastern Atlantic are more equivocal

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1029/2010JC006338
Programmes:	Oceans 2025 > Climate, ocean circulation and sea level
ISSN:	0148-0227
Additional Information. Not used in RCUK Gateway to Research.:	An edited version of this paper was published by AGU. Published 2010. Not subject to US Copyright Lumpkin, Rick Elipot, Shane National Science Foundation ; Environment and Climate EU ENACT project [EVK2-CT2001-00117]; CNES ; NASA ; AMSR-E Science Team Dave Fratantoni and John Lund deployed many of the CLIMODE drifters described in this paper, and numerous individuals and organizations are responsible for the historical deployments. The authors had valuable discussions with numerous colleagues; interactions with Angelique Haza, Tamay Ozgkmen, Shafer Smith, Joe LaCasce, Patrice Klein, John Toole, Kevin Speer, Carter Ohlmann, Javier Beron-Vera, Bill Dewer, and John Marshall were particularly enlightening. Mayra Pazos, Erik Vades, and Jessica Redman prepared the quality-controlled drifter data for this study. Shaun Dolk and Craig Engler managed worldwide drifter deployments and orchestrated the ADB drifter clusters. This work was supported by the National Science Foundation as part of the CLIMODE project. Additional support was provided by NOAA's Office of Climate Observations and the Atlantic Oceanographic and Meteorological Laboratory. The AVISO product was produced by the CLS Space Oceanography Division as part of the Environment and Climate EU ENACT project (EVK2-CT2001-00117) and with support from CNES. Microwave SST data are produced by Remote Sensing Systems and sponsored by the NASA Earth Science REASON DISCOVER Project and the AMSR-E Science Team. Data are available at http://www.remss.com. Amer geophysical union Washington
Additional Keywords:	ATMOSPHERIC ENERGY SPECTRUM; CONSTANT LEVEL BALLOONS; DISPERSION; 2-DIMENSIONAL TURBULENCE; GEOSTROPHIC TURBULENCE; UPPER OCEAN; DIFFUSION; DYNAMICS CIRCULATION
Date made live:	24 Feb 2011 16:30 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/13623

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