The Southern Oscillation. Part III: Associations with the Trades and with the Trough in the Westerlies of the South Pacific Ocean

Differences of sea-level pressure between pairs of stations in the South Pacific Ocean are used to examine the trades and the trough in the westerlies during the development of the phase of the Southern Oscillation when pressures fall over the tropical Pacific, equatorial waters warm, and rainfall increases in many otherwise dry places. It is demonstrated that this phase is characterized by an appreciable enhancement of the annual cycle of the trades and the trough compared to the year before. The warm event of 1982 followed this pattern closely.