Australian dust storms: temporal trends and relationships with synoptic pressure distributions (1960-99)

Abstract

Mean-sea-level-pressure patterns of the main atmospheric circulation for Australia were created using principal component analysis and non-hierarchical cluster analysis. The patterns are related to dust storm occurrence from 95 meteorological stations across Australia during the period 1960-99. Dust storm stations were separated into two groups with distinct dust storm seasons: the spring-summer (September-February) dust storm group and the summer-autumn (December-May) dust storm group. Spring-summer dust storms are most likely controlled by the timing of non-precipitation cold fronts over southern and central Australia and limited by summer precipitation. The summer-autumn dust storms are most likely controlled by the length of the driest period of the year. The stations of the first group are located mainly in the interior of the continent, and those of the second group are located mainly near the coastal regions of southern and western Australia. The location of the subtropical Indian Ocean high is shown here to influence dust storm occurrence during both seasons. A more westward displacement of this pressure centre in the Great Australian Bight allows cold fronts to enter the continent and increase the potential for dust storm activity.