Abstract
The South Atlantic Dipole (SAD) is the main mode of coupled variability
between ocean and atmosphere on interannual and interdecadal timescales
on the South Atlantic Ocean. Its oceanic component is characterized by a
dipole of sea surface temperature (SST) anomalies between tropics and
extratropics, while the atmospheric part is linked with the South
Atlantic Subtropical High (SASH) variability. Some other important
factors can influence the SAD, for instance, variations in the Atlantic
Meridional Overturning Circulation (AMOC), which may alter the
distribution of physical properties of the ocean such as the SST. Given
the current background of anthropogenic global warming, some features
have contributed to alter AMOC, such as Greenland’s continental ice
melting and also the increase in Agulhas Leakage. Therefore, this work
aims to identify possible changes in the SAD pattern during the period
after industrial revolution (1851-2010). The SAD is the first mode found
through the Singular Value Decomposition (SVD) of SST and Mean Sea Level
Pressure (MSLP). This analysis was performed at intervals of 30 and 10
years, in order to encompass the interannual and interdecadal cycles of
the SAD oscillation, at the same time that it is possible to analyze
possible changes in the SAD throughout the study period (1851-2010).
Preliminary results show strong signs of changes in the SAD
configuration, both in its oceanic and atmospheric components, which
probably have impacts on the climate of the adjacent continents, which
will be further studied later. The analysis performed with NOAA-CIRES
20th Century Reanalysis V2c indicate a clockwise rotation of the SST
anomaly dipole pattern, while the associated MSLP anomalies show a
northwestern shift over the study period.