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The Detection of Large HNO3-Containing Particles in the Winter Arctic Stratosphere
D. W. Fahey,13*R.
S. Gao,1K. S. Carslaw,4J. Kettleborough,5P. J. Popp,13M. J. Northway,13J. C. Holecek,13S. C. Ciciora,13R. J. McLaughlin,1T. L. Thompson,1R. H. Winkler,1D. G. Baumgardner,6B. Gandrud,7P. O. Wennberg,89S. Dhaniyala,8K. McKinney,8Th. Peter,10R. J. Salawitch,11T. P. Bui,12J. W. Elkins,2C. R. Webster,11E. L. Atlas,7H. Jost,1213J. C. Wilson,14R. L. Herman,11A. Kleinböhl,15M. von
König15
Large particles containing nitric acid (HNO3) were
observed in the 1999/2000 Arctic winter stratosphere. These in situ
observationswere made over a large altitude range (16 to 21 kilometers) andhorizontal extent (1800 kilometers) on several airborne
samplingflights during a period of several weeks. With diameters of 10to 20 micrometers, these sedimenting particles have significantpotential to denitrify the lower stratosphere. A microphysicalmodel of
nitric acid trihydrate particles is able to simulatethe growth and
sedimentation of these large sizes in the lowerstratosphere, but the
nucleation process is not yet known. Accuratemodeling of the formation
of these large particles is essentialfor understanding Arctic
denitrification and predicting futureArctic ozone abundances.
1 Aeronomy Laboratory,
2 Climate Monitoring and Diagnostics Laboratory,
National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA.
3 Cooperative Institute for Research in
Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.
4 School of the Environment, University of Leeds,
Leeds LS2 9JT, UK.
5 Rutherford Appleton Laboratory,
Chilton, Didcot, OX 11 OQX, UK.
6 Universidad
Nacional Autónoma de México, Centro de Ciencias de la
Atmósfera, Ciudad Universitaria, 04510 Mexico DF, Mexico.
7 National Center for Atmospheric Research, Boulder,
CO 80307, USA.
8 Division of Geology and Planetary
Sciences,
9 Division of Engineering and Applied
Science, California Institute of Technology, Pasadena, CA 91125, USA.
10 Laboratorium für
Atmosphärenphysik, Eidgenössiche Technische Hochschule
Zürich, CH-8093 Zürich, Switzerland.
11 NASA Jet Propulsion Laboratory, Pasadena, CA
91109, USA.
12 NASA Ames Research Center, Moffett
Field, CA 94035, USA.
13 Bay Area Environmental
Research Institute, San Francisco, CA 94122, USA.
14 Department of Engineering, University of Denver,
Denver, CO 80208, USA.
15 Institute of
Environmental Physics, University of Bremen, D-28334 Bremen,
Germany.
*
To whom correspondence should be addressed. E-mail:
fahey{at}al.noaa.gov
