Annual cycle observations of aerosols capable of ice formation in central Arctic clouds

• Published in: Nature Communications
• Main Authors: Creamean, Jessie M., Barry, Kevin, Hill, Thomas C. J., Hume, Carson, DeMott, Paul J., Shupe, Matthew D., Dahlke, Sandro, Willmes, Sascha, Schmale, Julia, Beck, Ivo, Hoppe, Clara J. M., Fong, Allison, Chamberlain, Emelia, Bowman, Jeff, Scharien, Randall K., Persson, Ola
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Communications 2022
• Subjects: Arctic; Ice; permafrost; Sea ice; Swiss Polar Institute
• Online Access: http://hdl.handle.net/1828/14618; https://doi.org/10.1038/s41467-022-31182-x

The Arctic is warming faster than anywhere else on Earth, prompting glacial melt, permafrost thaw, and sea ice decline. These severe consequences induce feedbacks that contribute to amplified warming, affecting weather and climate globally. Aerosols and clouds play a critical role in regulating radiation reaching the Arctic surface. However, the magnitude of their effects is not adequately quantified, especially in the central Arctic where they impact the energy balance over the sea ice. Specifically, aerosols called ice nucleating particles (INPs) remain understudied yet are necessary for cloud ice production and subsequent changes in cloud lifetime, radiative effects, and precipitation. Here, we report observations of INPs in the central Arctic over a full year, spanning the entire sea ice growth and decline cycle. Further, these observations are size-resolved, affording valuable information on INP sources. Our results reveal a strong seasonality of INPs, with lower concentrations in the winter and spring controlled by transport from lower latitudes, to enhanced concentrations of INPs during the summer melt, likely from marine biological production in local open waters. This comprehensive characterization of INPs will ultimately help inform cloud parameterizations in models of all scales. This work was funded by the DOE ARM and Atmospheric System Research (ASR) programs (DE-AC05-76RL01830, DE-2204 SC0019745, DE-SC0019251, DESC0021341) for J.M.C., K.B., T.C.J.H., C.H., P.J.D. and M.D.S.; the U.S. National Science Foundation (NSF) Office of Polar Programs (OPP-1724551) for E.C. and J.B.; and the German Federal Ministry for Education and Research (BMBF) for C.J.M.H. and A.F. through financing the AWI Helmholtz Zentrum für Polar und Meeresforschung and the Polarstern expedition (N-2014-H-060_Dethloff). I.B. received funding from the Swiss National Science Foundation (grant no. 200021_188478). J.S. received funding from the Swiss Polar Institute and holds the Ingvar Kamprad Chair for Extreme Environments Research ...