How many days does a tropical cyclone cost a port? Storm exposure of 2,065 ports over 1980–2025 and the loss of daily port calls in 1,321 port–storm encounters
Bir tropikal siklon bir limana kaç güne mal olur? 2.065 limanın 1980–2025 fırtına maruziyeti ve 1.321 liman-fırtına karşılaşmasında günlük uğrak kaybı
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Abstract
The tropical cyclone risk of ports is known mostly from major damage events and from modelled hazard maps; how much activity is lost in an ordinary encounter, when a storm passes close to a port, has not been measured at global scale. In this study the storm tracks of the international best track archive for 1980–2025 are interpolated to hourly resolution and matched with 2,065 ports. A total of 13,061 encounters are identified in which a system of at least tropical-storm strength came within 100 km of a port; 44% of ports and 55% of cargo volume were affected at least once in forty-six years. Cargo-weighted exposure (1.89 encounters per decade) is above the port average (1.37). No statistically significant trend is found in the number of encounters, in hurricane-force encounters or in the mean latitude of encounters. An event study of 1,321 encounters in 2019–2026, built on daily port calls derived from satellite-based ship tracking, shows that calls fall to 28% of their normal level on the day of closest approach, and to 9% in hurricane-force storms. Activity returns to normal within two days; about one third of the loss of the first four days is recovered in the following five. Over a seventeen-day window the net loss averages 0.85 port-days (95% confidence interval 0.57–1.15): 0.66 in tropical storms, 1.16 in hurricanes and 2.03 in major hurricanes. The distribution of losses is skewed: 10% of events cause a loss of more than five days and account for 42% of the total loss. Combining exposure with the loss per event gives an expected annual loss of 0.13 days at the average port and 0.17 days weighted by cargo; it exceeds one day per year at only 24 ports. The findings indicate that port risk is concentrated in rare and severe events and not in frequent short interruptions.
Keywords
Tropical cyclone; Port disruption; Event study; Port calls; Climate risk; Resilience
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