Heterogeneous formation of polar stratospheric clouds – Part 2: Nucleation of ice on synoptic scales ...

• Main Authors: Engel, Ines, Luo, Beiping P., Pitts, Michael C., Poole, Lamont R., Hoyle, Christopher R., Grooß, Jens-Uwe, Dörnbrack, Andreas, Peter, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2013
• Subjects: Arctic
• Online Access: https://dx.doi.org/10.3929/ethz-b-000077400; http://hdl.handle.net/20.500.11850/77400

This paper provides compelling evidence for the importance of heterogeneous nucleation, likely on solid particles of meteoritic origin, and of small-scale temperature fluctuations, for the formation of ice particles in the Arctic stratosphere. During January 2010, ice PSCs (polar stratospheric clouds) were shown by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) to have occurred on a synoptic scale (~1000 km dimension). CALIPSO observations also showed widespread PSCs containing NAT (nitric acid trihydrate) particles in December 2009, prior to the occurrence of synoptic-scale regions of ice PSCs during mid-January 2010. We demonstrate by means of detailed microphysical modeling along air parcel trajectories that the formation of these PSCs is not readily reconciled with expectations from the conventional understanding of PSC nucleation mechanisms. The measurements are at odds with the previous laboratory-based understanding of PSC formation, which deemed direct heterogeneous ... : Atmospheric Chemistry and Physics, 13 (21) ...