[1] Teleconnections were first noted by the British meteorologist Sir Gilbert Walker in the late 19th century, through computation of the correlation between time series of atmospheric pressure, temperature and rainfall.
However, the model was soon invalidated when it was discovered that actual teleconnection patterns were nearly insensitive to the location of the forcing, in direct contradiction with the predictions offered by this simple picture.
Simmons and collaborators[6] showed that if a more realistic background state was prescribed, it would become unstable, leading to a similar pattern regardless of the location of the forcing, in accordance to observations.
More recent work has shown that most teleconnections from the tropics to the extratropics can be understood to surprising accuracy by the propagation of linear, planetary waves upon a 3-dimensional seasonally-varying basic state.
In Sir Gilbert Walker's time, a strong El Niño usually meant a weaker Indian monsoon, but this anticorrelation has weakened in the 1980s and 1990s, for controversial reasons.