A modelling study of winter circulation and precipitation anomalies associated with Australian region ocean temperatures

Abstract

We have forced a July model with idealised positive ocean temperature anomalies to the northwest and northeast of the Australian continent. In two additional experiments this forcing was confined to the northwest and to the northeast. The 500 hPa field undergoes significant increase over most of the tropics in each of the experiments. Large precipitation increases were simulated over and near each of the warm anomalies. In two of the experiments, despite the large changes over the adjacent oceans, little significant precipitation difference was simulated over the continent. The experiment with the sea-surface temperature anomaly to the northwest was the exception to this and in it much of the country experienced precipitation rate increases in excess of 1 mm day-1. The results taken together suggest that the addition of a similar anomaly to the northeast of the country serves to lessen the impact of the warmed waters to the northwest. -from Author