Remote influence of Interdecadal Pacific Oscillation on the South Atlantic meridional overturning circulation variability

• Published in: Geophysical research letters Vol. 43; no. 15; pp. 8250 - 8258
• Main Authors: Lopez, Hosmay, Dong, Shenfu, Lee, Sang‐Ki, Campos, Edmo
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 16.08.2016
• Subjects: Atlantic Meridional Overturning Circulation (AMOC); Atlantic Ocean; Circulation; Climate; Climate models; Convection; Correlation; Curl (vectors); Dipoles; Displays; Forces (mechanics); Geophysics; Height; Interdecadal Pacific Oscillation; Marine; Mathematical models; meridional overturning circulation; Ocean circulation; Ocean models; Planetary waves; Robustness; Rossby waves; Sea level; Sea surface; sea surface height; Strength; Stresses; teleconnections; Temperature (air-sea); Tropical climate; Variability; Wave forces; Westerlies; Wind; Wind stress; Wind stress curl; AS, South Atlantic; IS, Tropical Pacific
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2016GL069067

This study explores potential factors that may influence decadal variability of the South Atlantic meridional overturning circulation (SAMOC) by using observational data as well as surface‐forced ocean model runs and a fully coupled climate model run. Here we show that SAMOC is strongly correlated with the leading mode of sea surface height (SSH) variability in the South Atlantic Ocean, which displays a meridional dipole between north and south of 20°S. A significant portion (~45%) of the South Atlantic SSH dipole variability is remotely modulated by the Interdecadal Pacific Oscillation (IPO). Further analysis shows that anomalous tropical Pacific convection associated with the IPO forces robust stationary Rossby wave patterns, modulating the wind stress curl over the South Atlantic Ocean. A positive (negative) phase IPO increases (decreases) the westerlies over the South Atlantic, which increases (decreases) the strength of the subtropical gyre in the South Atlantic and thus the SAMOC. Key Points Observations and models are used to investigate what causes decadal variability of the South Atlantic MOC (SAMOC) A strong correlation is found between SAMOC and the leading mode of the South Atlantic sea surface height (SSH) variability Stationary Rossby wave and associated wind‐stress curl forced by the IPO drive the variability of the South Atlantic SSH and thus the SAMOC