21st-century strong wind and heavy precipitation hazards in the Asian monsoon region related to mesoscale convective systems: climatology, variability, and trends

Mesoscale convective systems (MCSs) occur frequently throughout the Asian monsoon region (AMR) and exhibit distinct spatial distribution patterns, often associated with extreme weather events, including heavy rainfall, hail and tornadoes. To assess the hazardous impacts of MCSs and enhance disaster warning and response strategies, this study develops a database of MCSs across the AMR study domain from 2001 to 2023 using half-hourly infrared brightness temperature data and further examines their relationships with weather hazards based on observational data. Results show that more than 50 % of total precipitation is associated with MCSs in most parts of the AMR study domain, providing further evidence for the important role of MCSs in regional precipitation. More than 70 % of heavy rainfall events (HREs) over land and 47 % of strong wind events (SWEs) in the Chinese mainland are associated with MCSs, indicating the relevance of MCSs to hazardous weather. Furthermore, over 70 % of hail and tornado occurrences in China co-occur with MCSs. Statistically significant increases in MCS activity are observed in eastern China, while statistically significant decreases are noted from western China to the Bay of Bengal. Notably, in eastern China and its adjacent seas (ECAS), the conditional probabilities of HREs and SWEs given MCS occurrence have been increasing at average annual rates of 2.77 % and 3.11 %, respectively. Given the increasing trends in MCS activity and the probability of hazard occurrence given MCS presence in eastern China, strengthening preventive measures against weather-related disasters in this region is imperative.