Seasonal climate summary southern hemisphere (summer 2005-06): a neutral ENSO state with strong climate contrasts across Australia

摘要

Atmospheric and oceanic conditions in the southern hemisphere for the austral summer 2005-06 are reviewed, with emphasis given to the Pacific Basin climate indicators and Australian rainfall and temperature patterns. The climate system remained in a neutral state of the El Nina-Southern Oscillation, although some diagnostics exhibited weak La Nina tendencies, particularly in the Pacific Ocean. Spatially, ocean patterns were representative of cool ENSO conditions particularly at depth, with cooler waters in the east and warmer waters in the west. However, anomaly values were not of significant magnitude to be classified as a La Nina event, and the timing was out of phase with a typical episode. Summer 2005-06 was a season of marked contrasts in Australian climate, with warm and dry conditions throughout much of eastern Australia in contrast to a cool and wet season in Western Australia. January 2006 was the month with the most anomalies, being very wet in northern and western Australia as the monsoon burst into action during the second half of the month. Record heat was also experienced in eastern Australia in January 2006, particularly in Queensland and New South Wales. Record heat towards the end of December also contributed towards 2005 being Australia’s warmest year on record.