Properties and mass transport differences across the Falkland Plateau between 1999 and 2010

Abstract. Decadal differences in the Falkland Plateau are studied from full-depth hydrographic data collected during the ALBATROSS (April 1999) and MOC2-Austral (February 2010) cruises. Differences in the upper 100 dbar are due to changes in the seasonal thermocline, as the ALBATROSS cruise took place in the austral fall while the MOC-Austral in summer. The intermediate water masses seem to be very sensible to the wind conditions existing on their formation area, showing cooling and freshening for the decade as consequence of a higher Antarctic Intermediate Water (AAIW) contribution and of a decrease of the Subantarctic Mode Water (SAMW) stratum. The deeper layers do not exhibit any significant change in the water masses properties. The Subantarctic Front (SAF) in 1999 is observed at 52.2–54.8° W with a relative mass transport of 32.6 Sv. In contrast, the SAF gets wider in 2010, stretching from 51.1° W to 57.2° W (the Falkland Islands), and weakening to 17.9 Sv. Changes in the SAF are mainly affecting the northward flow of Subantarctic Surface Water (SASW), SAMW and AAIW/ Antarctic Surface Water (AASW). The Polar Front (PF) carries 24.9 Sv in 1999 (49.8–44.4° W), while in 2010 (49.9–49.2° W) it narrows and strengthens to 37.3 Sv.