Ocean wave hazards induced by tropical cyclone along the Chinese coast: 44-year characteristics and variability

Under climate change, the northward shift of tropical cyclone (TC) centers and the increase in intensity over the Northwest Pacific have been confirmed, while understanding of the spatiotemporal changes in distribution and hazard of TC waves caused thereby remains unclear. Based on 44-year wave simulations using TOMAWAC model, Dangerous TC Wave (DTW) events are defined, and the spatiotemporal characteristics and interannual variation of TC wave hazards are systematically investigated. Results show that total frequency of DTW events decreases, while duration of single events rises significantly, indicating wave hazards are shifting from high-frequency to long-duration patterns. Spatially, dangerous wave footprints display a poleward migration driven by asymmetric expansion of TC wind fields. DTW center migrates northward at 0.446° per decade at peak wave intensity, faster than TC centers, substantially elevating hazards over East China Sea. TC wave hazard risk is assessed by calculating cumulative wave energy induced by average single DTW. Its peak exceeds 2000 kWh/m along eastern Hainan and southern Taiwan, while the coastlines with the sharpest increase in cumulative wave energy correspond to East China Sea coast and northeastern Taiwan. TC wave hazards also show a notable seasonal delay, with dangerous waves concentrating increasingly during the TC active season.