The South Atlantic Circulation Between 34.5°S, 24°S and Above the Mid‐Atlantic Ridge From an Inverse Box Model

Arumí-Planas, Cristina; Pérez‐Hernández, M. Dolores; Pelegrí, Josep Lluís; Vélez‐Belchí, P.; Emelianov, Mikhail; Hernández‐Guerra, A.; Cana, L.; Firing, Yvonne L.; García-Weil, L.; Santana-Toscano, Daniel; Hernández‐Guerra, Alonso

doi:10.1029/2022jc019614

Cited by 2 publications

(1 citation statement)

References 97 publications

(213 reference statements)

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“…This method is a classical approach to estimate AMOC and MHT (e.g., Dong et al, 2015Dong et al, , 2021Goes et al, 2015Goes et al, , 2020. However, inverse models are also widely used to calculate the AMOC (e.g., Arumí-Planas, et al, 2023;Caínzos et al, 2022;Hernández-Guerra et al, 2010;Lux et al, 2001). The geostrophic AMOC stream function is estimated from the adjusted velocities (v, Equations 2 and 3), and its strength is defined as the maximum value of the stream function at each timestep.…”

Section: Amoc and Mht Time Seriesmentioning

confidence: 99%

An ARGO and XBT Observing System for the Atlantic Meridional Overturning Circulation and Meridional Heat Transport (AXMOC) at 22.5°S

Pita,

Goes,

Volkov

et al. 2023

JGR Oceans

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Changes in the Atlantic Meridional Overturning Circulation (AMOC) and associated Meridional Heat Transport (MHT) can affect climate and weather patterns, regional sea levels, and ecosystems. Direct observations of the AMOC are still limited, particularly in the South Atlantic. This study establishes a cost‐effective trans‐basin section to estimate for the first time the AMOC and MHT at 22.5°S, using only sustained ocean observations. For this, an optimal mapping method that minimizes the difference between surface in situ dynamic height and satellite altimetry was developed to retrieve monthly temperature and salinity profiles from Argo and XBT data along the 22.5°S section. The mean states, as well as the interannual and seasonal changes of the obtained AMOC and MHT were compared with other products. The mean AMOC and MHT for 22.5°S are 16.3 ± 3.2 Sv and 0.7 ± 0.2 PW, respectively, showing stronger transports during austral fall/winter and weaker in spring. The high‐density XBT data available at the western boundary were vital for capturing the highly variable Brazil Current (BC), whose mean and variability was improved compared to other products. At 22.5°S, the North Atlantic Deep Water is divided into two cores that flow along both the western and the eastern boundaries near 2,500 m depth. Our results (a) suggest a greater influence of the western boundary current system on the AMOC variability at 22.5°S, (b) highlight the importance of high‐density in situ data for AMOC estimates, and (c) contribute to a better understanding of the AMOC and MHT variability in the South Atlantic.

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Section: Amoc and Mht Time Seriesmentioning

confidence: 99%

An ARGO and XBT Observing System for the Atlantic Meridional Overturning Circulation and Meridional Heat Transport (AXMOC) at 22.5°S

Pita,

Goes,

Volkov

et al. 2023

JGR Oceans

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Consistent picture of the horizontal circulation of the Atlantic Ocean over 3 decades

et al. 2023

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Abstract. The circulation in the Atlantic Ocean is marked by the complex system of pathways of the Atlantic Meridional Overturning Circulation (AMOC). These currents change meridionally due to the interaction with nearby water masses. Hydrographic data provide the opportunity to characterize these currents for the whole water column with high-resolution data over the last 30 years. Moreover, inverse methods enable the quantification of absolute zonal transports across these sections, determining the strength of each current at a certain latitude in terms of mass, heat, and freshwater, as well as their transport-weighted temperature and salinity. Generally, no changes can be found among decades for each of the currents in terms of transport or their properties. In the South Atlantic, the circulation describes the subtropical gyre affected by several recirculations. There are nearly 61 Sv entering from the Southern and Indian oceans at 45∘ S. The South Atlantic subtropical gyre exports 17.0 ± 1.2 Sv and around 1 PW northward via the North Brazil Current, as well as −55 Sv southward at 45∘ S into the Antarctic Circumpolar Current. In the North Atlantic, most of the transport is advected northward via the western boundary currents, which reduce their strength as they take part in convection processes in the subpolar North Atlantic, also reflected in the northward progress of mass and heat transport. Deep layers carry waters southward along the western boundary, maintaining similar values of mass and heat transport until the separation into an eastern branch crossing the mid-Atlantic Ridge in the South Atlantic. Abyssal waters originating in the Southern Ocean are distributed along the South Atlantic mainly through its western subbasin, flowing northward up to 24.5∘ N, subjected to an increasing trend in their temperature with time.

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The South Atlantic Circulation Between 34.5°S, 24°S and Above the Mid‐Atlantic Ridge From an Inverse Box Model

Cited by 2 publications

References 97 publications

An ARGO and XBT Observing System for the Atlantic Meridional Overturning Circulation and Meridional Heat Transport (AXMOC) at 22.5°S

An ARGO and XBT Observing System for the Atlantic Meridional Overturning Circulation and Meridional Heat Transport (AXMOC) at 22.5°S

Consistent picture of the horizontal circulation of the Atlantic Ocean over 3 decades

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