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Atlantic Multidecadal Oscillation (AMO)

The Atlantic Multidecadal Oscillation (AMO) index reflects an argued 50-80 year pattern of North Atlantic coupled ocean-atmosphere variability. It is associated with changes in rainfall over North America and Europe, the frequency of North American droughts, and the intensity of North Atlantic hurricanes. It may mask or exaggerate signals of global change, though the argument that it is a separate signal from the forced global change signal is disputed.

The term was introduced in a summary by Kerr (Science, 2000) of a study by Delworth and Mann (2000). The index was defined by Enfield, Mestas-Nuñez, and Trimble (Geophys. Res. Lett., 2001) as the North Atlantic SST anomaly north of the equator. NOAA/AOML has further information on their AMO page »

Data source and calculation

Calculated by NOAA/ESRL (CDC) (last update 15-JUL-2016).