I was inspired by David Dilley’s weather forecasting based upon Atlantic water pulsing into the Arctic Ocean (see post: Global Weather Oscillations). So I went looking for that signal in the AMO dataset, our best long-term measure of sea surface temperature variations in the North Atlantic.
ATLANTIC MULTI-DECADAL OSCILLATION (AMO)
For this purpose, I downloaded the AMO Index from Kaplan SST v.2, the unaltered and untrended dataset. By definition, the data are monthly average SSTs interpolated to a 5×5 grid over the North Atlantic basically 0 to 70N.
For an overview the graph below presents a comparison between Annual, March and September averages from 1856 to 2016 inclusive.
We see about 4°C difference between the cold month of March, and warm September. The overall trend is slightly positive at 0.27°C per century, about 10% higher in September and 10% lower in March. It is also clear that monthly patterns…
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