An Analysis of Historical Triggers of Landfalling Tropical Cyclones in NSW (#1054)
On average 11 TCs form close to Australia each year over the northern tropical latitudes. A fraction of these events has made landfall in NSW in the past, but with serious consequences. Accounting for 32% of the total population of Australia and growing rapidly, the impacts of future landfalling events within NSW could be catastrophic. Therefore, the aims of this study were to compile a database of NSW landfalling TC events as far back as possible and assess historical trends. Further, a range of unique pathways for landfalling TCs in NSW was identified using cluster analysis and the large-scale climate conditions that favour these pathways established. Findings were then compared with current literature on how these conditions may be impacted by anthropogenic climate change for future TC seasons. A total of 26 landfalling TCs were identified to have passed through NSW between 1900-2017. During this time there have been periods of enhanced and reduced TC activity, with a clear hiatus (absence of landfalling TCs) period post ~1980. Further, the cluster analysis identified four dominant TC pathways: 1) derived in the Pacific, with an extensive poleward decay and environmental conditions enhanced by the Indian Ocean; 2) Originating in the Gulf of Carpentaria/Arafura Sea, crossing into NSW from NT or QLD with unique environmental conditions associated with both the Pacific and Indian Oceans; 3) Coral Sea derived, influenced mainly by the Pacific (in particular La Nina); 4) generated in the SW Pacific region, making landfall on the northern NSW coast, solely Pacific driven. This study provides a significant contribution to our understanding of the spatial and temporal variability of NSW landfalling TC risk, which can assist in aiding councils, emergency services and communities in NSW to develop adaptive measures to combat such events in the future.