Meridional Overturning Circulation Transport Variability at 34.5 degrees S During 2009-2017: Baroclinic and Barotropic Flows and the Dueling Influence of the Boundaries

Author(s):Show less -

Meinen, Christopher S. ^[1] ; Speich, Sabrina ^[2] ; Piola, Alberto R. ^{[3, 4, 5]} ; Ansorge, Isabelle ^{[6, 7]} ; Campos, Edmo ^{[8, 9]} ; Kersale, Marion ^{[10, 1]} ; Terre, Thierry ^[11] ; Chidichimo, Maria Paz ^{[3, 5]} ; Lamont, Tarron ^{[12, 6, 7]} ; Sato, Olga T. ^[8] ; Perez, Renellys C. ^[1] ; Valla, Daniel ^{[3, 5]} ; van den Berg, Marcel ^[12] ; Le Henaff, Matthieu ^{[10, 1]} ; Dong, Shenfu ^[1] ; Garzoli, Silvia L. ^{[10, 1]}

Affiliation:Show less -

^[1] Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 - USA

^[2] Ecole Normale Super, IPSL, Lab Meteorol Dynam, Paris - France

^[3] Serv Hidrog Naval, Buenos Aires, DF - Argentina

^[4] Univ Buenos Aires, Dept Ciencias Atmosfera & Oceanos, Buenos Aires, DF - Argentina

^[5] Consejo Nacl Invest Cient & Tecn, Inst Francoargentino Estudios Clima & Sus Impacto, Buenos Aires, DF - Argentina

^[6] Univ Cape Town, Oceanog Dept, Rondebosch - South Africa

^[7] Univ Cape Town, Marine Res Inst, Rondebosch - South Africa

^[8] Univ Sao Paulo, Oceanog Inst, Sao Paulo - Brazil

^[9] Univ Fed Ceara, Ocean Sci Lab, Fortaleza, Ceara - Brazil

^[10] Univ Miami, Cooperat Inst Marine & Atmospher Studies, Miami, FL - USA

^[11] Univ Brest, Lab Oceanog Phys & Spatiale, IFREMER, CNRS, IRD, IUEM, Plouzane - France

^[12] Oceans & Coasts Res Branch, Dept Environm Affairs, Cape Town - South Africa

• Document type: Journal article
• Source: Geophysical Research Letters; v. 45, n. 9, p. 4180-4188, MAY 16 2018.
• Web of Science Citations: 12

Abstract

Six years of simultaneous moored observations near the western and eastern boundaries of the South Atlantic are combined with satellite winds to produce a daily time series of the basin-wide meridional overturning circulation (MOC) volume transport at 34.5 degrees S. The results demonstrate that barotropic and baroclinic signals at both boundaries cause significant transport variations, and as such must be concurrently observed. The data, spanning similar to 20 months during 2009-2010 and similar to 4 years during 2013-2017, reveal a highly energetic MOC record with a temporal standard deviation of 8.3 Sv, and strong variations at time scales ranging from a few days to years (peak-to-peak range = 54.6 Sv). Seasonal transport variations are found to have both semiannual (baroclinic) and annual (Ekman and barotropic) timescales. Interannual MOC variations result from both barotropic and baroclinic changes, with density profile changes at the eastern boundary having the largest impact on the year-to-year variations. (AU)

• FAPESP's process: 17/09659-6 - Interannual variability of the meridional transports across the SAMOC basin-wide array (SAMBAR)
• Grantee: Edmo José Dias Campos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 11/50552-4 - Impact of the Southern Atlantic on the global overturning circulation (MOC) and climate (SAMOC)
• Grantee: Edmo José Dias Campos
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants