Change in the occurrence frequency of landfalling and non-landfalling tropical cyclones over the Northwest Pacific

摘要

Understanding the tropical cyclone (TC) activity changes in response to climate change is of great importance for disaster mitigation and climate change adaptation. Change in the annual occurrence frequency of landfalling and non-landfalling weak, strong, and super TCs during 1980-2018 was analyzed. Results indicate that the super TCs have been more likely to make landfall in the northwest Pacific since 1980. Using an empirical orthogonal function-based method proposed to decompose the space-time field of TC occurrence into different patterns, the anthropogenic influence on the change in super TC occurrence was detected when the impacts of E) Nino-Southern Oscillation (ENSO), the Pacific meridional mode (PMM), and the inter-decadal Pacific oscillation (IPO) were separated. Results further show that TCs forming in the sea surface near land (6°21 °N, 130°-137°E) have been more likely to intensify to super TCs in recent years. These intensified TCs tend to favor subsequent landfall, which may be the reason for the increase in landfalling super TCs. The intensification of TC is mainly due to the increase in the intensification rate, which increases with increased sea surface temperature (SST), especially during the stronger wind periods. Along with the change in the occurrence of landfalling super TCs, the landfalling locations of super TCs also changed. For example, western South China, Southeast China, and Japan are facing an increase in landfalling super TCs. The destructive-ness of super TCs to these economically developed and highly populated regions is great; more attention therefore should be paid to mitigate TC disasters.