A 10,000-Year Global Stochastic Tropical Cyclone Catalog with Wind-Dependent Track Transitions (WHITS)

2026-05-19

AI Summary

Historical tropical cyclone records suffer from limited spatiotemporal coverage, hindering reliable assessment of catastrophic risk from rare, intense landfalling events. This study proposes WHITS—a wind-speed-dependent nonparametric semi-Markov trajectory generation model—that, for the first time, incorporates local wind speed into path transition probabilities. By integrating optimized kernel selection with trajectory smoothing techniques, WHITS effectively mitigates dynamically inconsistent jumps and state discontinuities. Using multi-basin IBTrACS data, the model generates a 10,000-year global synthetic cyclone catalog that closely reproduces observed patterns in both track density and frequency of high-intensity wind strikes. The resulting catalog significantly enhances the physical plausibility and low-bias performance of catastrophe risk assessments.

Abstract

Reliable assessment of tropical cyclone (TC) risk is limited by the brevity and spatial sparsity of the historical record, particularly for the rare, high-intensity landfalls that dominate insured loss. We present WHITS (Wind-focused Hurricane Interactive Track Simulator), a non-parametric semi-Markov track generator that extends the HITS framework of Nakamura et al. (2015) in three ways: transitions between historical track segments are conditioned on local wind speed in addition to position, age, and forward vector; the kernel selection on the comparative-vector term is sharpened to suppress dynamically inconsistent jumps; and a short smoothing window is applied across each transition to remove the position and wind discontinuities reported by downstream surge users. WHITS is fit to the full available best-track record in each of six basins in IBTrACS, extending in the North Atlantic to 1851 and in other basins to the earliest year of reliable best-track data. The resulting 10,000-yr global synthetic catalog reproduces observed track density and the annual hurricane/typhoon-force wind-hit probability across all basins. The catalog is intended for catastrophe-risk applications where a large, low-bias sample of physically plausible tracks is more useful than a small, statistically corrected one.

Problem

• tropical cyclone risk
• historical record sparsity
• high-intensity landfalls
• catastrophe-risk assessment

Innovation

• stochastic track simulation
• wind-dependent transitions
• semi-Markov model
• synthetic tropical cyclone catalog
• catastrophe risk modeling