Publication Date:
2015-10-02
Description:
The Southern Ocean plays a critical role in global climate, yet the mixing properties of the circulation in this part of the ocean remain poorly understood. Here, dispersion in the vicinity of the Southern Antarctic Circumpolar Current Front, one of the branches of the Antarctic Circumpolar Current, is studied using ten pairs of surface drifters deployed systematically across the frontal jet and its flanks. Drifter pairs were deployed with an initial separation of 13m and report their position every hour. The separation of the pairs over seven months, in terms of their Finite Scale Lyaponuv Exponents (FSLE), dispersion, and diffusivity, is characterized and related to expected behavior from Quasi-geostrophic (QG) and Surface Quasi-geostrophic (SQG) theories. The FSLE analysis reveals two submesoscale regimes, with SQG-like behavior at scales below 3.2km and mixed QG/SQG behavior at scales between 3.2km and 73km. The dispersion analysis, however, suggests QG-like behavior for the smallest scales. Both dispersion and diffusivity appear isotropic for scales up to 500km. Finally, there is no clear indication of a cross-jet variation of drifter dispersion. This article is protected by copyright. All rights reserved.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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