AN ENSO SIGNAL IN SOYBEAN FUTURES PRICES

An example of socioeconomic repercussions of the El Nino-Southern Osci llation (ENSO) is examined. Multichannel singular spectrum analysis, a variant of principal component analysis useful in isolating the spati al and temporal variability associated with anharmonic oscillations, i s applied to normalized monthly mean time series of soybean futures pr ices and the Southern Oscillation index. The method isolates the varia bility common to the two time series from the remaining variability an d noise. It identifies the low- and high-frequency, quasibiennial mode s of ENSO as part of this variability.