On the late twentieth century decrease in Australian east coast rainfall extremes

A change from negative to positive circulation anomalies over New South Wales ( NSW) during the 1970s resulted in a decrease in east coastal low-pressure systems and accompanying rain. Negative pressure anomalies over eastern Australia, anomalous onshore low-level winds and larger NSW rainfall totals since 1950, occur in the cool phase of the IPO rather than the warm phase (post-1976). Larger NSW extreme annual rainfall totals occurred prior to 1977 and were characterized by negative mean sea level pressure (MSLP) anomalies over eastern Australia. In contrast, extreme annual rainfall totals from 1977 were smaller and characterized by positive MSLP anomalies. Copyright (c) 2008 Royal Meteorological Society