The atmospheric component
tied to El Niño is termed the “Southern Oscillation.”
Scientists often call the phenomenon where the atmosphere
and ocean collaborate together ENSO, short for
El Niño–Southern Oscillation. El Niño then corresponds
to the warm phase of ENSO. The opposite
“La Niña” (“the girl” in Spanish) phase consists of a
basinwide cooling of the tropical Pacific and thus the
cold phase of ENSO. However, for the public, the term
for the whole phenomenon is “El Niño.”