Norwegian meteorologist Jacob Bjerknes is the first to see a connection
between unusually warm sea-surface temperatures in El Niño and the weak
easterlies and heavy rainfall that accompany Southern Oscillation
conditions. Ultimately, Bjerknes' discovery leads to the recognition that
the warm waters of El Niño and the pressure seesaw of Walker's Southern
Oscillation are facets of the same phenomenon, sometimes referred to by the
acronym ENSO, or El Niño/Southern Oscillation.