Abstract
Abstract. Decadal differences in the Falkland Plateau are studied from the two full-depth hydrographic data collected during the ALBATROSS (April 1999) and MOC-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 and the MOC-Austral cruise in summer. The intermediate water masses seem to be very sensitive to the wind conditions existing in their formation area, showing cooling and freshening for the decade as a consequence of a higher Antarctic Intermediate Water (AAIW) contribution and of a decrease in the Subantarctic Mode Water (SAMW) stratum. The deeper layers do not exhibit any significant change in the water mass 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 to 57.2° W (the Falkland Islands), and weakening to 17.9 Sv. Changes in the SAF can be linked with the westerly winds and mainly affect 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.
Highlights
The Antarctic Circumpolar Current (ACC) flows eastwards around the Antarctic continent, transporting roughly between 100 and 173 Sv (1 Sv = 106 m3 s−1 ≈ 109 kg s−1; hereafter Sv will be the unit used) (Orsi et al, 1995; Cunningham et al, 2003; Donohue et al, 2016)
Several studies have later examined the path of the Polar Front (PF) around the Maurice Ewing Bank (Trathan et al, 2000) and its branching around 49–50◦ W
The Antarctic Intermediate Water (AAIW) + Antarctic Surface Water (AASW) stratum of the MOC-Austral cruise presents a minimum that consists of temperatures below 1.2 ◦C and salinities around 34
Summary
Peterson and Whitworth III (1989) suggested that the Subantarctic Front (SAF) and the Polar Front (PF), where the major velocity bands of the ACC occur, turn northwestward across the Falkland Plateau to the west of the Maurice Ewing Bank, along the Patagonian continental slope This was supported by Peterson (1992), who estimated the large contribution of the ACC to the Falkland Current (60– 70 Sv), revealing the importance of the overflow of southern waters to the South Atlantic boundary circulation. This section was compared with hydrographic cruises carried out north and south of the Falkland Plateau to achieve a better knowledge of this area (Arhan et al, 2002; Smith et al, 2010). Changes in water masses are decomposed into changes in the θ/S isobaric surfaces and results from the Bindoff and McDougall (1994) model
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
