Seasonal climate summary southern hemisphere (autumn 1997) : rapid onset of a negative phase of the Southern Oscillation (El Niño)

Southern hemisphere circulation patterns and anomalies for autumn (March-May) 1997 are reviewed, with emphasis given to Pacific Basin climate indicators, and Australian rainfall and temperature patterns. A rapid fall in the Southern Oscillation Index coincided with the spread of drier than normal conditions over southeastern Australia, and an abrupt cessation of the monsoon in the north of the country. In addition, strong warming of the surface and subsurface of the eastern Pacific occurred in response to sustained low-level equatorial westerly wind anomalies in the western Pacific and associated Kelvin waves.