q Jacob Bjerknes was the first one to recognizes that El
Nino is not just an oceanic phenomenon (in his 1969 paper).
q In stead, he hypothesized that the warm waters of El
Nino and the pressure seasaw of Walker’s Southern Oscillation are
part and parcel of the same phenomenon: the
ENSO.
q Bjerknes’s hypothesis of coupled atmosphere-ocean
instability laid the foundation for ENSO research.