Increased dependency of regional drought termination on landfalling tropical cyclones

Landfalling tropical cyclones frequently occur with strong winds and heavy rainfall, providing substantial water resources. The positive impacts of tropical cyclones on drought alleviation and termination remain unknown. Here, we estimate the dependency of drought terminations on tropical cyclone rainfall through frequency analyses and event coincidence analysis. Results show that ~3% of the tropical cyclone-affected areas have experienced multiple drought events terminated by tropical cyclone rainfall from 1999 to 2021. Globally, tropical cyclone-terminated drought events averaged 1.12 annually and increased significantly by 1.92% per year. Increases were especially significant in the Arabian Peninsula, South Asia, and the northwest of Australia. Rainfall produced by tropical cyclones alleviates drought events more drastically than that by other weather systems, such as fronts, mesoscale convective systems, and atmospheric rivers. These findings underscore the adaptation of precipitation changes due to shifts in the timing and weather systems under a warming climate. Tropical cyclone rainfall terminated drought events on average of 1.1 times per year globally from 1999 to 2021, with a significant annual increase of 1.9%, particularly in the Arabian Peninsula, South Asia, and northwest of Australia, according to the frequency and event coincidence analyses