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Rapid intercontinental air pollution transport associated with a meteorological bomb

Cyclones are a key element of the atmospheric circulation in the midlatitudes (Carlson, 1998). Cyclogenesis, for which a first conceptual model was presented by the Bergen school (Bjerknes, 1910), occurs most frequently at the polar front. The various ascending and descending airstreams typically associated with these cyclones carry a range of different chemical signatures (Cooper et al., 2002). The so-called warm conveyor belt (WCB) – a strongly ascending airstream ahead of a cyclone’s cold front (Browning et al., 1973) – is an important mechanism to lift air pollutants emitted at the sur- face into the upper troposphere, where the faster winds facil- itate their intercontinental transport (ICT) (Stohl and Trickl, 1999). Thus,. | Atmos. Chem. Phys. 3 969-985 2003 www.atmos-chem-phys.org acp 3 969 Atmospheric Chemistry and Physics Rapid intercontinental air pollution transport associated with a meteorological bomb A. Stohl1 H. Huntrieser2 A. Richter3 S. Beirle4 0. R. Cooper5 S. Eckhardt1 C. Forster1 P. James1 N. Spichtinger1 M. Wenig6 T. Wagner4 J. P. Burrows3 and U. Platt4 1Department of Ecology Technical University of Munich Germany 2Institute for Atmospheric Physics DLR Oberpfaffenhofen Germany 3Institute of Environmental Physics University of Bremen Germany institute of Environmental Physics Heidelberg University Germany 5Cooperative Institute for Research in Environmental Sciences CIRES University of Colorado NOAA Aeronomy Laboratory Boulder USA 6NASA Goddard Space Flight Center Code 916 Greenbelt MD USA Received 19 February 2003 - Published in Atmos. Chem. Phys. Discuss. 16 April 2003 Revised 20 June 2003 - Accepted 8 July 2003 - Published 9 July 2003 Abstract. Intercontinental transport ICT of trace substances normally occurs on timescales ranging from a few days to several weeks. In this paper an extraordinary episode in November 2001 is presented where pollution transport across the North Atlantic took only about one day. The transport mechanism termed here an intercontinental pollution express highway because of the high wind speeds was exceptional as it involved an explosively generated cyclone a so-called meteorological bomb . To the authors knowledge this is the first study describing pollution transport in a bomb. The discovery of this event was based on tracer transport model calculations and satellite measurements of NO2 a species with a relatively short lifetime in the atmosphere which could be transported that far only because of the high wind speeds produced by the bomb. A 15-year transport climatology shows that intercontinental express highways are about four times more frequent in winter than in summer in agreement with bomb climatologies. The climatology furthermore .