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An ARGO and XBT observing system for the Atlantic Meridional Overturning Circulation and Meridional Heat Transport (AXMOC) at 22.5ºS
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  • Ivenis Pita,
  • Marlos Pereira Goes,
  • Denis L. Volkov,
  • Shenfu Dong,
  • Gustavo J. Goni,
  • Mauro Cirano
Ivenis Pita
Rosenstiel School, University of Miami

Corresponding Author:[email protected]

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Marlos Pereira Goes
University of Miami/CIMAS and NOAA/AOML
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Denis L. Volkov
University of Miami / AOML
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Shenfu Dong
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Gustavo J. Goni
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Mauro Cirano
Universidade Federal do Rio de Janeiro
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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. However, despite its importance, direct observations of the AMOC are still limited spatially and temporally, particularly in the South Atlantic. The main goal of this study is to implement a cost-effective trans-basin section to estimate for the first time the AMOC 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 AMOC and MHT for 22.5°S were estimated as 15.55±2.81 Sv and 0.68±0.18 PW, respectively, and are stronger during austral fall/winter and weaker in spring. The high-resolution XBT data available at the western boundary are vital for capturing the highly variable Brazil Current, and our section shows a significant improvement when compared to Argo database. The mean values, interannual and seasonal time series of AMOC and MHT were compared with other products. At 22.5S the North Atlantic Deep Water is divided into two cores that flow along both western and eastern boundaries near 2500 m depth. Our results suggest a greater influence of western boundary system on the AMOC variability at 22.5°S; highlight the importance of high resolution in situ data for AMOC estimations; and contribute for a better understanding of AMOC and MHT variability in the South Atlantic.
31 May 2023Submitted to ESS Open Archive
01 Jun 2023Published in ESS Open Archive