Impact of uncertainty induced by fatality function on future tropical cyclone risk assessment.

Tropical cyclones (TCs) are among the deadliest extreme events occurring under a warming climate. Future TC risk assessment depend on TC projection from climate models and impact function relating TC to its possible consequence. Few studies have explored the uncertainty of impact function in future TC risk assessment compared to uncertainty in future TC characteristics. In this study, we investigate the uncertainty in TC fatality risk assessment induced by geographic and TC category-dependence of fatality function. We focus on all provinces in the mainland of China with historically recorded TC-induced fatalities and examine their TC fatality risks by assessing the difference in the annual average fatalities between current and future climate conditions. Synthetic TCs derived from four climate models and fatality functions parameterized from three grouped historical TC disaster datasets are used to observe the uncertainty induced by climate model and fatality function. Results show that the changes in the TC frequency, wind, TC-induced rainfall intensity, and exposure due to climate change in each province are dependent on the climate models. And the changes in the annual average fatality of each province are dependent on both the climate models and fatality functions. Climate models play a dominant role in determining the spatial pattern of future risk, while the fatality functions can alter the direction and magnitude of the risk change for certain provinces. Our results highlight the role of fatality function in detecting future TC risk under climate change, and inspire further TC impact studies that consider the heterogeneity of both climate conditions and geographical locations.