¥Not really an extension – given 3 modes, most often space, time, climate
variable, choose one as ÔvariableÕ, one as
ÔobservationÕ, ignore the third, and do PCA. 6
possibilities.
¥S-mode most usual: space = variables, time = observations.
¥T-mode, not uncommon: time = variables, space = observations.