Intrathermocline eddies in the coastal transition zone off central Chile (31-41°S)

• DOI: 10.1002/jgrc.20337
• Publication Date: 2013-08-08T15:30:04Z
• Authors: Samuel Hormazabal; Vincent Combes; Carmen E. Morales; Marco A. Correa-R...; Emmanuel Di Lorenzo; Sergio Nuñez
• Keywords: Eddy

[1] The three-dimensional structure and the origin of mesoscale anticyclonic intrathermocline eddies (ITEs) in coastal transition zone (CTZ) off central Chile (31–41°S) were analyzed through combination data from oceanographic cruises satellite altimetry, application an eddy-resolving primitive equation ocean model coupled with a numerical experiment using passive tracer. In this region, ITEs are represented by subsurface lenses (∼100 km diameter; 500 m thickness or vertical extension) nearly homogeneous salinity (>34.5) oxygen-deficient (<1.0 mL L−1) waters, properties which linked to equatorial water mass (ESSW) transported poleward Peru-Chile undercurrent (PCUC) band. At least five seven observed simultaneously area between 31° 38°S during winter 1997 2009. Satellite indicated that identified situ moved westward, each at mean speed ∼2 d−1 total volume ∼1 × 106 m3 s−1 (=1 Sv); lifespan ITE ranged few months 1 year. Model results indicate become detached PCUC under summer upwelling conditions zone.