Articles | Volume 18, issue 11
Research article
13 Jun 2018
Research article |  | 13 Jun 2018

Sensitivity of atmospheric aerosol scavenging to precipitation intensity and frequency in the context of global climate change

Pei Hou, Shiliang Wu, Jessica L. McCarty, and Yang Gao

Abstract. Wet deposition driven by precipitation is an important sink for atmospheric aerosols and soluble gases. We investigate the sensitivity of atmospheric aerosol lifetimes to precipitation intensity and frequency in the context of global climate change. Our sensitivity model simulations, through some simplified perturbations to precipitation in the GEOS-Chem model, show that the removal efficiency and hence the atmospheric lifetime of aerosols have significantly higher sensitivities to precipitation frequencies than to precipitation intensities, indicating that the same amount of precipitation may lead to different removal efficiencies of atmospheric aerosols. Combining the long-term trends of precipitation patterns for various regions with the sensitivities of atmospheric aerosol lifetimes to various precipitation characteristics allows us to examine the potential impacts of precipitation changes on atmospheric aerosols. Analyses based on an observational dataset show that precipitation frequencies in some regions have decreased in the past 14 years, which might increase the atmospheric aerosol lifetimes in those regions. Similar analyses based on multiple reanalysis meteorological datasets indicate that the changes of precipitation intensity and frequency over the past 30 years can lead to perturbations in the atmospheric aerosol lifetimes by 10 % or higher at the regional scale.

Short summary
Atmospheric aerosols can be affected not only by emissions, but also meteorology, in particular precipitation. Analyses of the historical meteorological data based on multiple datasets show significant changes in precipitation characteristics, including precipitation intensity and frequency, over various regions around the world. We find that the precipitation changes over the past 30 years can easily lead to perturbations in atmospheric aerosols by 10 % or higher at the regional scale.
Final-revised paper