>No series of SST blog posts would be complete without a view of the Atlantic Ocean SST and Anomaly data. Refer to Figure 1, which illustrates Northern and Southern Hemisphere SST anomalies for the Atlantic, from January 1854 to May 2008, both data sets smoothed with a 37-month filter. The North Atlantic displays the well-documented cycles associated with thermohaline circulation. In the South Atlantic, that cycle is visible, but it’s been suppressed significantly by time and mass. The South is also impacted by other influences that give it the spikes that peak around 1940 and 1975. The Northern SST anomaly curve appears to have topped out recently, possibly heralding a downturn in the AMO. The Southern anomaly has been relatively flat for almost 20 years.
In Figure 2, I’ve shortened the time span to from January 1979 to present. The data has not been smoothed. The South Atlantic appears to be on a slow downward trend that started 10 to 12 years ago. The North Atlantic might be declining, though it’s tough to tell with data that noisy.
For reference, I’m providing a glimpse at monthly SST data for the North and South Atlantic, from January 1979 to present, in Figure 3.
Sea Surface Temperature Data is Smith and Reynolds Extended Reconstructed SST (ERSST.v2) available through the NOAA National Operational Model Archive & Distribution System (NOMADS).