Seasonal climate summary southern hemisphere (spring 2000): a third successive positive phase of the Southern Oscillation begins

Atmospheric and oceanic conditions in the southern hemisphere are reviewed for the 2000 austral spring season. Particular emphasis is given to the Australian and Pacific regions. After a neutral winter, Southern Oscillation Index (SOI) values rose during the spring, achieving positive values for the third year in succession. The high SOI observed later in the season was reflected in the rainfall and maximum and minimum temperatures for Australia, with above average rainfall totals over much of the continent (resulting in flooding in northern New South Wales and southern Queensland), and cooler (warmer) temperatures in the northern (southern) regions. However, oceanic El Niño – Southern Oscillation (ENSO) indicators remained near normal, suggesting the ENSO state for spring 2000 was neutral. Elsewhere, outgoing long wave radiation values suggested the South Pacific convergence zone was southwest of its springtime climatological position. Mean sea-level pressure over Australia was generally near normal, with positive anomalies in the Tasman Sea associated with increased blocking. Over the Antarctic, the springtime ozone hole expanded to its largest size on record, peaking in area at over 28 million square kilometres early in the season.