Energetics and Dynamics of Subtropical Australian East Coast Cyclones: Two Contrasting Cases

AbstractThe subtropical east coast region of Australia is characterized by the frequent occurrence of low pressure systems, known as east coast lows (ECLs). The more intense ECLs can cause severe damage and disruptions to this region. While the term “east coast low” refers to a broad classification of events, it has been argued that different ECLs can have substantial differences in their nature, being dominated by baroclinicand barotropic processes in different degrees. Here we reexamine two well-known historical ECL case studies under this perspective: the Duck stormof March 2001 and the PashaBulker stormof June 2007. Exploiting the cyclone phase space analysis to study the storms’ full three-dimensional structure, we show that one stormhas features similar to a typical extratropical frontal cyclone, while the other has hybrid tropical–extratropical characteristics. Furthermore, we examine the energetics of the atmosphere in a limited area including both systems for the ECL occurrence times, and sh...