Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 14709-14726, 2017
https://doi.org/10.5194/acp-17-14709-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
11 Dec 2017
The observed influence of local anthropogenic pollution on northern Alaskan cloud properties
Maximilian Maahn1,2, Gijs de Boer1,2, Jessie M. Creamean1,2, Graham Feingold2, Greg M. McFarquhar3, Wei Wu4,5, and Fan Mei6 1University of Colorado, Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado, USA
2National Oceanographic and Atmospheric Administration, Earth System Research Laboratory, Boulder, Colorado, USA
3University of Oklahoma, Cooperative Institute for Mesoscale Meteorological Studies, Norman, Oklahoma, USA
4University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
5National Center for Atmospheric Research, Boulder, Colorado, USA
6Pacific Northwest National Laboratory, Richland, Washington, USA
Abstract. Due to their importance for the radiation budget, liquid-containing clouds are a key component of the Arctic climate system. Depending on season, they can cool or warm the near-surface air. The radiative properties of these clouds depend strongly on cloud drop sizes, which are governed in part by the availability of cloud condensation nuclei. Here, we investigate how cloud drop sizes are modified in the presence of local emissions from industrial facilities at the North Slope of Alaska. For this, we use aircraft in situ observations of clouds and aerosols from the 5th Department of Energy Atmospheric Radiation Measurement (DOE ARM) Program's Airborne Carbon Measurements (ACME-V) campaign obtained in summer 2015. Comparison of observations from an area with petroleum extraction facilities (Oliktok Point) with data from a reference area relatively free of anthropogenic sources (Utqiaġvik/Barrow) represents an opportunity to quantify the impact of local industrial emissions on cloud properties. In the presence of local industrial emissions, the mean effective radii of cloud droplets are reduced from 12.2 to 9.4 µm, which leads to suppressed drizzle production and precipitation. At the same time, concentrations of refractory black carbon and condensation nuclei are enhanced below the clouds. These results demonstrate that the effects of anthropogenic pollution on local climate need to be considered when planning Arctic industrial infrastructure in a warming environment.

Citation: Maahn, M., de Boer, G., Creamean, J. M., Feingold, G., McFarquhar, G. M., Wu, W., and Mei, F.: The observed influence of local anthropogenic pollution on northern Alaskan cloud properties, Atmos. Chem. Phys., 17, 14709-14726, https://doi.org/10.5194/acp-17-14709-2017, 2017.
Publications Copernicus
Short summary
Liquid-containing clouds are a key component of the Arctic climate system and their radiative properties depend strongly on cloud drop sizes. Here, we investigate how cloud drop sizes are modified in the presence of local emissions from industrial facilities at the North Slope of Alaska using aircraft in situ observations. We show that near local anthropogenic sources, the concentrations of black carbon and condensation nuclei are enhanced and cloud drop sizes are reduced.
Liquid-containing clouds are a key component of the Arctic climate system and their radiative...
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