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Incoming links: The North Atlantic Oscillation by Met Office
North Atlantic Oscillation Created 2026-10-13 Updated 2026-11-05
The North Atlantic Oscillation is variability in the large-scale North Atlantic atmospheric pressure gradient, commonly summarized by an index comparing the subtropical high-pressure region with the subpolar low-pressure region. A stronger-than-usual contrast characterizes a positive phase and is associated with stronger Atlantic westerly winds; a weaker contrast changes the preferred paths of weather systems.[ref]
The North Atlantic Oscillation by Met Office. Definition, north-south pressure contrast and positive/negative circulation regimes
The index is useful because it connects a broad circulation pattern to regional temperature and rainfall variability. It does not imply one repeating fixed-period oscillation, nor does its sign uniquely determine the weather at every location. A station-based index and an index fitted to a spatial pattern need not be numerically identical.