Eddy-induced cross-shelf export of high Chl-a coastal waters in the SE Bay of Biscay

REMOTE SENSING OF ENVIRONMENT

卷:205

Article

Rubio, Anna¹  Caballero, Ainhoa¹  Orfila, Alejandro²  Hernandez-Carrasco, Ismael³  Ferrer, Luis¹  Gonzalez, Manuel¹  Solabarrieta, Lohitzune⁴  Mader, Julien¹ 

[1] AZTI Marine Res, Portualdea Z-G, Pasaia 20110, Spain

[2] IMEDEA CSIC UIB, Marine Technol & Operat Oceanog Dept, Esporles, Spain

[3] SOCIB Balearic Isl Coastal Observing Syst, Parc Bit,Edificio Naorte,2nd Floor, Palma De Mallorca 07121, Spain

[4] King Abdullah Univ Sci & Technol KAUST, Red Sea Res Ctr RSRC, Biol & Environm Sci & Engn Div BESE, Thuwal 239556900, Saudi Arabia

关键词: Ocean mesoscale eddies;    Cross-shelf transport;    FSLE;    Remote sensing;    High-Frequency Radar;    Lagrangian Coherent Structures;    Lagrangian connectivity maps;   

DOI  :  10.1016/j.rse.2017.10.037

来源: Elsevier

【 摘 要 】

Different remote sensing data were combined to characterise a winter anticyclonic eddy in the southeastern Bay of Biscay and to infer its effects on cross-shelf exchanges, in a period when typical along shelf-slope currents depict a cyclonic pattern. While the joint analysis of available satellite data (infrared, visible and altimetry) permitted the characterisation and tracking of the anticyclone properties and path, data from a coastal high-frequency radar system enabled a quantitative analysis of the surface cross-shelf transports associated with this anticyclone. The warm core anticyclone had a diameter of around 50 km, maximum azimuthal velocities near 50 cm s(-1) and a relative vorticity of up to -0.45f. The eddy generation occurred after the relaxation of a cyclonic wind-driven current regime over the shelf-slope; then, the eddy remained stationary for several weeks until it started to drift northwards along the shelf break. The surface signature of this eddy was observed by means of high-frequency radar data for 20 consecutive days, providing a unique opportunity to characterise and quantify, from a Lagrangian perspective, the associated transport and its effect on the Chl-a surface distribution. We observed the presence of mesoscale structures with similar characteristics in the area during different winters within the period 2011-2014. Our results suggest that the eddy-induced recurrent cross-shelf export is an effective mechanism for the expansion of coastal productive waters into the adjacent oligotrophic ocean basin.

【 授权许可】

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