Recent Daily MOC Variability Estimates at 34.5°S from in situ Observations and Comparisons with Estimates at 26.5°N

Sabrina Speich, Ecole Normale Supérieure Paris, Paris, France, Christopher S Meinen, Atlantic Oceanographic and Meteorological Laboratory, Physical Oceanography Division, Miami, FL, United States, Edmo J Campos, USP University of Sao Paulo, São Paulo, Brazil, Alberto R Piola, Servicio de Hidrografía Nava, Buenos Aires, Argentina, Silvia Lucia Garzoli, NOAA/AONL/PhOD, Miami, FL, United States, Michael John Roberts, Department of Environmental Affairs, Cape Town, South Africa, Isabelle Jane Ansorge, university of Cape Town, Department of Oceanography, Cape Town, South Africa, Renellys C Perez, UM/CIMAS, Miami, FL, United States, Shenfu Dong, University of Miami, Miami, FL, United States, Thierry Terre, Ifremer, Laboratoire de Physique des Océans, Plouzané, France and Marcel Van den Berg, Department of Environmental Affairs, Oceans & Coasts Research Branch, Cape Town, South Africa
Abstract:
Research under the auspices of the South Atlantic Meridional Overturning Circulation (SAMOC) international initiative has demonstrated the significance of MOC variability at the ‘entrance’ of the Atlantic at 34.5°S. A monitoring experiment designed to assess the capability of deep moored arrays together with Argo profiling floats and remote sensed data was implemented in 2008-2009. The purpose of the array is to: 1) estimate the MOC in the South Atlantic; 2) infer regional water masses transformation, pathways and variability; and 3) identify the dynamical processes driving water masses exchanges and transformations. Data from the trans-basin array along 34.5°S and from Argo are combined to produce daily in situ time series observations of the basin-wide MOC. In this presentation we revisit the estimates of the daily MOC strength at 34.5°S obtained during a ~20 month long pilot array between 2009 and 2010 with recently recovered data covering almost three additional years (2012-2015). The observed MOC variability (amplitude and frequency distribution) is compared to both snapshot estimates from high-resolution XBT transects and continuous measurements from satellite altimetry. The new results are also compared to the long-term (10-year) estimates from the 26.5°N RAPID/MOCHA/WBTS array. The resulting variability is partitioned in terms of total, Ekman, geostrophic and boundary volume transport components.
Back to: Observing and Modeling the Meridional Overturning Circulation in the South Atlantic: Causes of Variability and Impacts on Climate, Weather, and Ecosystems I