The tropical Atlantic is home to multiple coupled climate variations covering a wide range of timescales and impacting societally relevant phenomena such as continental rainfall, Atlantic hurricane activity, oceanic biological productivity, and atmospheric circulation in the equatorial Pacific. The tropical Atlantic also connects the southern
SUMMARY: We use hydrographic, velocity and drifter data from a cruise carried out in November 2008 to describe the continental slope current system in the upper thermocline (down to 600 m) between Cape Verde and the Canary Islands. The major feature in the region is the Cape Verde Frontal Zone (CVFZ), separating waters from tropical (southern) and subtropical (northern) origin. The CVFZ is found to intersect the slope north of Cape Blanc, between 22°N and 23°N, but we find that southern waters are predominant over the slope as far north as 24°N. South of Cape Blanc (21.25°N) the Poleward Undercurrent (PUC) is a prominent northward jet (50 km wide), reaching down to 300 m and indistinguishable from the surface Mauritanian Current. North of Cape Blanc the upwelling front is found far offshore, opening a near-slope northward path to the PUC. Nevertheless, the northward PUC transport decreases from 2.8 Sv at 18°N to 1.7 Sv at 24°N, with about 1 Sv recirculating ofshore just south of Cape Blanc, in agreement with the trajectory of subsurface drifters. South of the CVFZ there is an abrupt thermohaline transition at s q =26.85 kg m -3 , which indicates the lower limit of the relatively pure (low salt and high oxygen content) South Atlantic Central Water (SACW) variety that coexists with the dominant locallydiluted (salinity increases through mixing with North Atlantic Central Water but oxygen diminishes because of enhanced remineralization) Cape Verde (SACWcv) variety. At 16°N about 70% of the PUC transport corresponds to the SACW variety but but this is transformed into 40% SACWcv at 24°N. However, between Cape Verde and Cape Blanc and in the 26.85
The influx of warmer and saltier Indian Ocean waters into the Atlantic—the Agulhas leakage—is now recognized to play an important role in the global thermohaline circulation and climate. In this study the results of a ⅞° simulation with the Hybrid Coordinate Ocean Model, which exhibit an augmentation in the Agulhas leakage, is investigated. This increase in the leakage ought to have an impact on the meridional oceanic volume and heat transports in the Atlantic Ocean. Significant linear trends found in the integrated transport at 20°, 15°, and 5°S correlate well with decadal fluctuations of the Agulhas leakage. The augmented transport also seems to be related to an increase in the latent heat flux observed along the northeastern coastline of Brazil since 2003. This study shows that the precipitation on the Brazilian coast has been increasing since 2005, at the same location and with the same regime shift observed for the latent heat flux and the volume transport. This suggests that the increase of the Agulhas transport affects the western boundary system of the tropical Atlantic Ocean, which is directly related to an increase in the precipitation and latent heat flux along the western coast.
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.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.