Location, Area, Curvature and Temporal Trends of Coral Sea Tropical Cyclone Tracks, Over 50 Years

Abstract

Tropical Cyclones (TCs) with genesis in the Coral Sea, often near the east coast of Australia, present significant hazards to coastal regions in their surroundings. There has, therefore, been significant recent efforts to extract information from records of their historical tracks in order to help predict their future behaviour in the light of a changing climate. In this study, the Australian Bureau of Meteorology (BOM) database of TC tracks over the last fifty years were grouped based on K-means clustering of the maximum wind-weighted centroids. Track shape variance and track curvature (sinuosity) were assessed. Three well defined clusters of TC tracks were identified, and the results showed predominant directions of TC movement by cluster. Track sinuosity was shown to increase from east to west. Only one cluster showed a statistically significant trend (decreasing) in TC frequency. The concept of TC power dissipation index (PDI) was introduced, revealing that two of the clusters have diverging trends for PDI post 2004. The location of cyclone maximum intensity (LMI) was trended, and only one cluster showed a statistically significant trend (towards the equator) for LMI. All these findings demonstrated a clear variance in risk between the clusters and suggests that this method of cluster analysis is a useful and productive complementary tool when establishing future impacts of TCs - the method identifies divergent TC characteristics and trends at a finer scale (cluster) level which then aids in assigning specific and differing TC risk mitigation strategies to different areas of the Australian east coast.