Southern Annular Mode
There are several climate patterns that influence the distribution of weather around the world. The most widely discussed of these is the El Niño-Southern Oscillation (ENSO). However, it is the Southern Annular Mode, or SAM, that has the largest effect on how the climate varies in our part of the world: the Southern Hemisphere and Aotearoa New Zealand.
El Niño and La Niña
ENSO is short for El Niño-Southern Oscillation. It is a climate oscillation, or a long term see-saw in atmospheric and ocean conditions across the Pacific Ocean. There are three phases of ENSO: El Niño, La Niña, and Neutral. Each phase brings a change to the winds, sea surface temperatures, and rainfall across the globe and here in Aotearoa New Zealand.