Multiple thermal fronts near the Patagonian shelf break

BÁRBARA C. FRANCO; ALBERTO R. PIOLA; ANDRÉS L. RIVAS; ANA BALDONI; JUAN P. PISONI

GEOPHYSICAL RESEARCH LETTERS

American Geophysical Union

Lugar: Washington D.C.; Año: 2008 vol. 35 p. 1 - 6

0094-8276

Eighteen year (1985–2002) sea surface temperature(SST) data are used to study the intraseasonal variability ofthe Patagonian shelf break front (SBF) in the SW SouthAtlantic Ocean between 39º and 44ºS. The cross-shelf breakSST gradients reveal distinct, previously undocumentedthermal fronts located both, offshore and inshore of theSBF. Throughout the year the main SBF, identified as aband of negative SST gradient maxima (relatively strongoffshore temperature decrease), forms a persistent featurelocated closed to the 200 m isobath, while two distinctnegative gradient maxima are located inshore and offshoreof this location. Daily SST images reveal the presence ofthree branches of cold waters whose edges delineate theabove mentioned fronts. The two offshore branches closelyfollow lines of constant potential vorticity (f/h) and appearto be associated with the Malvinas Current, while a thirdbranch, located further onshore, is not steered by the bottomtopography. South of 40ºS the onshore branch forms a quasipermanent front parallel to the SBF.