Increased rainfall volume from future convective storms in the US

• Published in: Nature climate change 2017-12, Vol.7 (12), p.880-884
• Main Authors: Prein, Andreas F., Liu, Changhai, Ikeda, Kyoko, Trier, Stanley B., Rasmussen, Roy M., Holland, Greg J., Clark, Martyn P.
• Format: Article
• Language: English
• Subjects: 704/106/242; 704/106/35/823; 704/106/694/2786; Adaptation; Atmospheric precipitations; Climate; Climate Change; Climate Change/Climate Change Impacts; Climate models; Computer simulation; Convection; Convective storms; Earth and Environmental Science; Economic models; Environment; Environmental Law/Policy/Ecojustice; Environmental risk; Flood management; Flood protection; Flood risk; Floods; Heavy precipitation; Investment; Letter; Management systems; Maximum precipitation; Mesoscale convective systems; Precipitation; Protection; Rain; Rainfall; Storms; Water management
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/s41558-017-0007-7

Mesoscale convective system (MCS)-organized convective storms with a size of ~100 km have increased in frequency and intensity in the USA over the past 35 years 1 , causing fatalities and economic losses 2 . However, their poor representation in traditional climate models hampers the understanding of their change in the future 3 . Here, a North American-scale convection-permitting model which is able to realistically simulate MSCs 4 is used to investigate their change by the end-of-century under RCP8.5 (ref. 5 ). A storm-tracking algorithm 6 indicates that intense summertime MCS frequency will more than triple in North America. Furthermore, the combined effect of a 15–40% increase in maximum precipitation rates and a significant spreading of regions impacted by heavy precipitation results in up to 80% increases in the total MCS precipitation volume, focussed in a 40 km radius around the storm centre. These typically neglected increases substantially raise future flood risk. Current investments in long-lived infrastructures, such as flood protection and water management systems, need to take these changes into account to improve climate-adaptation practices. Limitations with climate models have previously prevented accurate diagnosis of future changes in mesoscale convective systems (MCSs). A convection-permitting model now indicates that summer MCSs will triple by 2100 in the United States, with a corresponding increase in rainfall rates and areal extent.