Direct Measurements of the Malvinas Current Velocity Structure

Abstract

The cold Malvinas Current (MC) is one of the main circulation patterns in the southwestern South Atlantic Ocean (Peterson & Whitworth III, 1989). This current originates as a branch of the Antarctic Circumpolar Current (ACC) (Provost et al., 1996), rounds east of the Falklands/Malvinas Islands, and flows northward along the continental slope of South America (Figure 1) (Willson & Rees, 2000). The MC follows the Subantarctic Front (SAF), one of three main fronts of the ACC in the Drake Passage (Barre et al., 2011;Sokolov & Rintoul, 2009). It is generally accepted that the MC starts near the Burdwood Bank at around 55°S; upstream from the sharp northward turn of the SAF, the flow is referred to as the northern branch of the ACC (Artana et al., 2016). At approximately 38°S, the MC meets with the Brazil Current, generating a thermohaline front known as the Brazil Malvinas Confluence zone (Brennecke, 1921;Deacon, 1937). Further downstream, both currents retroflect and instabilities generate prominent mesoscale structures (Chelton et al., 1990;Zyrjanov & Severov, 1979). On average, the front intersects the

Climate Change Impacts on the Patagonian Shelf Break Front

“…Since the latitude of northernmost MC penetration is also associated with a sharp increase in SST, we compared the gADT derived location of the MC with the location of the maximum along‐slope SST gradient (gradySST). To calculate gradySST, we averaged the SST between the 300 and 1800 m isobaths, where the core of MC is located (Frey et al., 2021). We applied a 1‐degree x 1‐degree low‐pass filter to the SST data to eliminate noise and calculated the along‐slope gradient of SST.…”

Revisiting the Malvinas Current Upper Circulation and Water Masses Using a High‐Resolution Ocean Reanalysis

“…The MC is an equivalent‐barotropic current that flows along the Patagonian continental slope with surface velocities of the order of 60 cm/s (Figure 1b). Observations suggest that the MC is organized in two narrow jets at 45°S (Frey et al., 2021; Piola et al., 2013). Poli et al.…”

“…The MC is an equivalent-barotropic current that flows along the Patagonian continental slope with surface velocities of the order of 60 cm/s (Figure 1b). Observations suggest that the MC is organized in two narrow jets at 45°S (Frey et al, 2021;Piola et al, 2013). Poli et al (2020) showed that shelf break trapped waves modulate the intensity of the inner jet -SAF-N branch-while slow waves propagating from the Malvinas Escarpment and the Drake Passage modify velocities in the main jet-SAF-M branch-(Figure 2a).…”

Seamless Integration of the Coastal Ocean in Global Marine Carbon Cycle Modeling

“…Liu et al, 2019;Pätsch et al, 2017). The transport rates of boundary and slope currents, for instance, are underestimated in our low-res runs but become more energetic in the high-res simulation, for example, with increases of the Malvinas Current along the PS by 20% (high-res mean 20.7 Sv at 45°S, literature 20-25 Sv by Frey et al [2021]), the NWES slope current by 35% (high-res mean 2.4 Sv at 58°N, literature 1-4 Sv by Marsh et al [2017] and Clark et al [2021]), and shelf break upwelling velocities by a factor of 4. On the shelves, the general patterns of the circulation and seasonal stratification are comparatively similar in both configurations (Figure A4), though become more structured and confined in high-res.…”

“…The transport rates of boundary and slope currents, for instance, are underestimated in our low‐res runs but become more energetic in the high‐res simulation, for example, with increases of the Malvinas Current along the PS by 20% (high‐res mean 20.7 Sv at 45°S, literature 20–25 Sv by Frey et al. [2021]), the NWES slope current by 35% (high‐res mean 2.4 Sv at 58°N, literature 1–4 Sv by Marsh et al. [2017] and Clark et al.…”