The multiscale variability of global extreme wind and wave events and their relationships with climate modes

Abstract

Extreme winds and waves threaten human life, property security, infrastructure, and marine engineering. Persistent extreme wind events (EWiEs) and extreme wave events (EWaEs) can cause more significant impacts and destruction than short-term or instantaneous extreme events. This study defines an EWiE (EWaE) as a prolonged discrete event characterized by abnormally high wind speeds (significant wave heights). The climatological characteristics, spatiotemporal variability, and long-term trends of EWaEs and EWiEs globally are studied utilizing ERA5 reanalysis datasets from 1940 to 2021. The climatological mean characteristics of EWiEs and EWaEs are generally similar: extratropical regions exhibit high intensities, high counts, and short durations, whereas tropical regions are characterized by weak intensities, low counts, and long durations. The count and duration of EWaEs have significantly increased globally, with the greatest rate in the equatorial Pacific Ocean, where the count of events has increased by more than 2.1/decade and the duration by more than 7.2 h/decade. Furthermore, the Southern Annular Mode (SAM) exhibits a significant positive correlation with the count and duration of EWaEs in the eastern Pacific and Southern Oceans. In the Southern Hemisphere at 0–30°S, the Atlantic Multidecadal Oscillation (AMO) shows a significant positive correlation with the count of EWaEs and EWiEs.