The observed influence of local anthropogenic pollution on northern Alaskan cloud properties

Liquid-containing clouds are a key component of the Arctic climate system because they can cool or warm the near-surface air. The properties of these clouds depend strongly on cloud drop sizes, which are affected in part by the amount of aerosols present. In a new study published in Atmospheric Chemistry and Physics, CIRES and NOAA researchers at the Earth System Research Laboratories (ESRL) and collaborators use aircraft observations to investigate the impact of local pollution on Arctic liquid cloud properties They compare cloud properties at Oliktok Point, Alaska, which is surrounded by the Prudhoe Bay oilfield, with cloud properties at the more atmospherically pristine Utqiaġvik (formerly Barrow), Alaska. Their findings suggest that local pollution likely has an impact on liquid cloud properties.

The researchers find that the concentration of certain air pollution markers is enhanced in the Oliktok Point region. Collocated liquid clouds feature a reduction of cloud drop size. The smaller drop size impacts cloud processes and reduces the transformation of cloud drops into drizzle drops, possibly impacting the lifetime of the clouds.

Liquid containing clouds are a key component of the Arctic climate system, because they can warm and cool the surface depending on the season. Therefore, any changes of Arctic cloud properties might have an impact on local climate.

You can read a related news feature at CIRES: Local Air Pollution on Alaska's North Slope Changes Cloud Properties

Foothills on the North Slope of Alaska. Credit: Jason Tomlinson, PNNL
Foothills on the North Slope of Alaska. Credit: Jason Tomlinson, PNNL
Foothills on the North Slope of Alaska. Credit: Jason Tomlinson, PNNL

Authors of The observed influence of local anthropogenic pollution on northern Alaskan cloud properties are: Maximillian Maahn, Gijs de Boer, and Jessie Creamean of the ESRL Physical Sciences Laboratory, Graham Feingold of the ESRL Chemical Sciences Laboratory, Greg McFarquhar of University of Oklahoma, Wei Wu of University of Illinois and National Center for Atmospher Research, and Fan Mei of the Pacific Northwest National Laboratory.