Southwest pacific extreme tropical cyclone wind risk and its sensitivity to sea surface temperature
摘要
Tropical cyclones (TC) pose significant threat to the western region of southwest Pacific Ocean basin (SWPO). This study evaluates the risk of strongest TCs impacting northeast and eastern Australia and SWPO Island nations using an extreme value theory (EVT) on a hexagonal tessellated domain. The goal is to model extreme TC return level for specified return period. EVT computed latent variables including threshold, rate, scale, and shape of the extreme wind distribution, and the 30 and 20 year return levels are mapped. The 30 year return level shows 60 ms−1 or category 5 TCs can be expected over the Vanuatu and Fiji Islands, whereas category 4 TC can be expected near the coastal Queensland and New Caledonia regions. Fiji, New Caledonia, Vanuatu, and its surrounding ocean can expect TCs with 55 to 60 ms−1 wind speed in every 20 years. Quantitative analysis of regional sea surface temperature effect on both the 30 and 20 years return levels is done using a geographically weighted regression. Result suggests that 30 years return level is more sensitive to the changes in SST than 20 years return level. This geographic-level assessment of extreme TC return levels is crucial for regional planning and emergency preparation.
Graphical abstract