Effect of anomalous warming in the central Pacific on the Australian monsoon

Abstract

The influence of sea surface temperature (SST) anomalies in the central Pacific Ocean on rainfall variability over Australia is investigated using observations and idealized simulations from an atmospheric general circulation model. We show that the SST warming centered at 180°W is associated with increased monsoon precipitation over northern Australia from January to February and a decrease in December and March over the same region, leading to a shorter and more intense monsoon period. In recent years SST anomalies commonly associated with El Niño events have often exhibited a peak signature in the central, not eastern, Pacific. These so-called El Niño Modoki events are shown here to result in a markedly shorter and more intense Australian monsoon season. Copyright 2009 by the American Geophysical Union.