Effects of long-range aerosol transport on the microphysical properties of low-level liquid clouds in the Arctic

The properties of low-level liquid clouds in the Arctic can be altered by long-range pollution transport to the region. Satellite, tracer transport model, and meteorological data sets are used here to determine a net aerosol–cloud interaction (ACInet) parameter that expresses the ratio of relative c...

Full description

Bibliographic Details
Published in:Atmospheric Chemistry and Physics
Main Authors: Coopman, Quentin, Garrett, Timothy J., Riedi, Jérôme, Eckhardt, Sabine, Stohl, Andreas
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2016
Subjects:
Online Access:https://doi.org/10.5194/acp-16-4661-2016
https://noa.gwlb.de/receive/cop_mods_00043792
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043412/acp-16-4661-2016.pdf
https://acp.copernicus.org/articles/16/4661/2016/acp-16-4661-2016.pdf
Description
Summary:The properties of low-level liquid clouds in the Arctic can be altered by long-range pollution transport to the region. Satellite, tracer transport model, and meteorological data sets are used here to determine a net aerosol–cloud interaction (ACInet) parameter that expresses the ratio of relative changes in cloud microphysical properties to relative variations in pollution concentrations while accounting for dry or wet scavenging of aerosols en route to the Arctic. For a period between 2008 and 2010, ACInet is calculated as a function of the cloud liquid water path, temperature, altitude, specific humidity, and lower tropospheric stability. For all data, ACInet averages 0.12 ± 0.02 for cloud-droplet effective radius and 0.16 ± 0.02 for cloud optical depth. It increases with specific humidity and lower tropospheric stability and is highest when pollution concentrations are low. Carefully controlling for meteorological conditions we find that the liquid water path of arctic clouds does not respond strongly to aerosols within pollution plumes. Or, not stratifying the data according to meteorological state can lead to artificially exaggerated calculations of the magnitude of the impacts of pollution on arctic clouds.