Substantial Contribution of Anthropogenic Air Pollution to Catastrophic Floods in Southwest China

TitleSubstantial Contribution of Anthropogenic Air Pollution to Catastrophic Floods in Southwest China
Publication TypeJournal Article
Year of Publication2015
JournalGeophysical Research Letter
Volume42
Date Published07/2015
Abstract

Extreme weather events have become more frequent and are likely linked to increases in greenhouse gases and aerosols, which alter the Earth's radiative balance and cloud processes. On 8–9 July 2013, a catastrophic flood devastated the mountainous area to the northwest of the Sichuan Basin. Atmospheric simulations at a convection-permitting scale with aerosols and chemistry included show that heavy air pollution trapped in the basin significantly enhances the rainfall intensity over the mountainous areas through “aerosol-enhanced conditional instability.” That is, aerosols suppress convection by absorbing solar radiation and increasing atmospheric stability in the basin during daytime. This allows excess moist air to be transported to the mountainous areas and orographically lifted, generating strong convection and extremely heavy precipitation at night. We show that reducing pollution in the Sichuan Basin can effectively mitigate floods. It is suggested that coupling aerosol with meteorology can be crucial to improve weather forecast in polluted regions.

URLhttp://onlinelibrary.wiley.com/wol1/doi/10.1002/2015GL064479/full
DOI10.1002/2015GL064479
Journal: Geophysical Research Letter
Volume: 42

Extreme weather events have become more frequent and are likely linked to increases in greenhouse gases and aerosols, which alter the Earth's radiative balance and cloud processes. On 8–9 July 2013, a catastrophic flood devastated the mountainous area to the northwest of the Sichuan Basin. Atmospheric simulations at a convection-permitting scale with aerosols and chemistry included show that heavy air pollution trapped in the basin significantly enhances the rainfall intensity over the mountainous areas through “aerosol-enhanced conditional instability.” That is, aerosols suppress convection by absorbing solar radiation and increasing atmospheric stability in the basin during daytime. This allows excess moist air to be transported to the mountainous areas and orographically lifted, generating strong convection and extremely heavy precipitation at night. We show that reducing pollution in the Sichuan Basin can effectively mitigate floods. It is suggested that coupling aerosol with meteorology can be crucial to improve weather forecast in polluted regions.

DOI: 10.1002/2015GL064479
Year of Publication: 2015
Citation:
2015.  "Substantial Contribution of Anthropogenic Air Pollution to Catastrophic Floods in Southwest China."  Geophysical Research Letter 42, doi:10.1002/2015GL064479.