Seasonal climate summary southern hemisphere (summer 1987-88): decline of the warm phase Southern Oscillation event

Climate anomalies during the austral summer of 1987/88 are summarised and an attempt is made to identify the dynamical processes associated with the establishment of the longer term circulation anomalies. A shift in the mid-latitude planetary wave train occurred in conjunction with a relocation of the zonal maximum in tropical convective activity from the western Pacific to the Indonesian region during a quiescent phase of the tropical 40 to 50-day oscillation in mid-summer. Stable patterns of pressure and tropospheric height anomalies in the periods before and after the reorganisation of the wave train produced persistent weather conditions in a number of locations around the hemisphere. Circulation anomalies which had characterised the warm phase Southern Oscillation (SO) during the preceding season weakened.