Journal Article

Intensification of Mesoscale Convective Systems in the East Asian Rainband Over the Past Two Decades

Li, Puxi, Zhuang, Moran, Schiemann, Reinhard, Chen, Haoming, Prein, Andreas F., Furtado, Kalli, Zhou, Tianjun, Muetzelfeldt, Mark, Li, Chao, Song, Fengfei, Li, Jian, Zhang, Wenxia

2023

Overview

As one of the major producers of extreme precipitation, mesoscale convective systems (MCSs) have received much attention. Recently, MCSs over several hotpots, including the Sahel and US Great Plains, have been found to intensify under global warming. However, relevant studies on the East Asian rainband, another MCS hotpot, are scarce. Here, by using a novel rain‐cell tracking algorithm on a high spatiotemporal resolution satellite precipitation product, we show that both the frequency and intensity of MCSs over the East Asian rainband have increased by 21.8% and 9.8% respectively over the past two decades (2000–2021). The more frequent and intense MCSs contribute nearly three quarters to the total precipitation increase. The changes in MCSs are caused by more frequent favorable large‐scale water vapor‐rich environments that are likely to increase under global warming. The increased frequency and intensity of MCSs have profound impacts on the hydroclimate of East Asia, including producing extreme events such as severe flooding. Plain Language Summary Mesoscale convective systems (MCSs), accounting for more than half of the total rainfall in the East Asian rainband, frequently generate high‐impact extreme weather events, such as flooding. In the summer of 2020, large regions of East Asia suffered extensive flooding and damage. Therefore, understanding the long‐term changes of MCSs is crucial to gain insights into how extreme weather may change in the context of global warming. However, compared to several other MCS hotpots, the investigation of long‐term changes of MCSs is scarce over East Asia. Here, based on a high spatiotemporal resolution satellite precipitation product and a novel MCS tracking method, we find that MCSs have become more frequent and intense in the East Asian rainband and accounted for three quarters of the total rainfall increase during 2000–2021. It is further found that increases in atmospheric total column water vapor, which is mainly due to increased temperature caused by anthropogenic forcing, leads to more frequent large‐scale water vapor‐rich environments that are responsible for the intensification of MCSs. As water vapor increases with global warming, it is very likely that MCSs will continue to intensify in this region into the future. Key Points Mesoscale convective systems (MCSs) have become more frequent and intense in the East Asian rainband over the past two decades The significant increase of MCS precipitation accounted for three quarters of the total rainfall increase during 2000–2021 The increase of atmospheric total column water vapor, mainly driven by anthropogenic forcing, leads to more favorable environments for MCSs

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Algorithms / Anthropogenic factors / atmospheric total column water vapor / Climate change / Extreme weather / Flood damage / Flooding / Floods / Global warming / Human influences / Hydroclimate / large‐scale environments / long‐term changes / Mesoscale convective systems / Mesoscale phenomena / Precipitation / Rain / Rainbands / Rainfall / Rainfall increase / Satellites / Tracking / Water vapor / Water vapour / Weather