The Malvinas Current (MC), a major western boundary current of the South Atlantic Ocean, is an offshoot of the Antarctic Circumpolar Current (Figure 1a) that flows northward following the Subantarctic Front (SAF) along the eastern continental slope of South America. The MC, which borders one of the widest continental shelves of the world, is strongly controlled by bottom topography. Between 52°S and 49°S, the bottom slope is west-east orientated and gentle (2,000 m over 300 km) and the MC is rather wide (300 km) with mean northward surface velocities of 30 cm/s (Figures 1a and 1b). At 48°S, isobaths are east-west orientated and the MC mean surface velocities are zonal with a mean value of 40 cm/s. The largest mean surface velocities in the MC (>60 cm/s) are observed north of 43°S where the bottom slope is steep (Figures 1a and 1b) and the MC is organized in one narrow jet. South of 43°S, the MC is characterized by a relatively stable two-jet structure alienated with two bottom terraces (Piola et al., 2013). The mean location of the onshore jet corresponds to a northern branch of the SAF (SAF-N), while the main jet follows the main SAF along the 1,500-m isobath (Figure 1b; Artana et al., 2018). At 38°S, the MC encounters the Brazil Current forming the Brazil-Malvinas Confluence. The surface eddy kinetic energy (EKE) at this region is among the greatest in the world ocean with values exceeding 2,000 cm 2 /s 2 (Figure 1c). In contrast, the EKE in the MC is rather small (200 cm 2 /s 2) since the Malvinas Plateau filters a large part of the mesoscale activity from Drake Passage (Artana et al., 2016). In situ observations have pointed at the possible existence of trapped waves (TW) propagating northward along the Patagonian slope. Velocity spectra obtained from current-meter moorings deployed at 41°S across the slope near the Brazil Malvinas Confluence showed large energy peaks between 5 and 110 days (Vivier & Provost, 1999; Vivier et al., 2001). Despite these observations, there is still no characterization of TW along the Patagonian slope. As the TW propagates rapidly, they are not entirely resolved in satellite-altimetry-derived maps of sea level anomalies (SLAs) (Ballarotta et al., 2019).
The Malvinas Current (MC), a major western boundary current of the South Atlantic, is the northernmost meander of the northern branch of the Antarctic Circumpolar Current (ACC), the Subantarctic Front (SAF). The North Scotia Ridge in Drake Passage (Figure 1a) acts as a barrier to the ACC fronts forcing the SAF and Polar Front (PF) branches to deviate to the north. The two SAF branches (SAF-N and SAF-M) cross the North Scotia Ridge west (600 m) and east (2,000 m) of Burdwood Bank (WBB and EBB, respectively), while the two northern branches of the PF (PF-M and PF-N) proceed through Shag Rocks Passage (3,200 m, SRP) (Figure 1a). Subsequently, the SAF branches cross the shallow Malvinas Plateau (<3,000 m) and continue their path northward forming the MC, while the PF follows an eastward path along the Malvinas Escarpment (Figure 1a). 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). The MC is concentrated in a narrow single jet at 41°S and encounters the Brazil Current (BC) at 38°S. Then part of the BC, referred to as the overshoot of the BC, flows southward and returns to the northeast at about 45°S while the MC splits in two branches: the inner branch keeps flowing northward sinking
We investigated wintertime convection evolution in recent years over the Greenland Sea. This area is a major location regarding dense water production and supply of the lower limb of the Atlantic Meridional Overturning Circulation, a key component of the global climate. Previous studies mentioned an increase in Greenland Sea wintertime convection intensity during the 2000s in comparison with the previous decade till 2015/2016. Here, we further document the ongoing oceanic changes within the Greenland Sea through the Mercator Ocean Physical System, an operational ocean model with data‐assimilation. The model has shown a large variability, a later start and a decline of convection in the Greenland Sea in recent years. In particular, the depth of the annual maximum mixed layer diminished by 52% between 2008–2014 and 2015–2020, from 1,168 to 559 m, over the convective area. This decline of the convection depth is corroborated with Argo float observations. Within the Greenland Sea, hydrographic changes especially the increasing temperature are associated with isopycnal deepening and stratification strengthening. The stratification is building up at a larger rate in the Boreas Basin compared to the Greenland Basin. The changes of the Greenland Sea hydrography in the model are in part related to Atlantic Water spreading over the Boreas Basin and the eastern part of the Greenland Basin. The model also indicates a decrease in the intensity of the gyre in accordance with the isopycnal deepening while local surface winds and fluxes do not exhibit significant trends nor significant interannual variations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.