The observation of nitric acid-containing particles in the tropical lower stratosphere
| Autor: | P. J. Popp, T. P. Marcy, E. J. Jensen, B. Kärcher, D. W. Fahey, R. S. Gao, T. L. Thompson, K. H. Rosenlof, E. C. Richard, R. L. Herman, E. M. Weinstock, J. B. Smith, R. D. May, H. Vömel, J. C. Wilson, A. J. Heymsfield, M. J. Mahoney, A. M. Thompson |
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| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: | |
| Zdroj: | Atmospheric Chemistry and Physics, Vol 6, Iss 3, Pp 601-611 (2006) |
| Druh dokumentu: | article |
| ISSN: | 1680-7316 1680-7324 |
| Popis: | Airborne in situ measurements over the eastern Pacific Ocean in January 2004 have revealed a new category of nitric acid (HNO3)-containing particles in the tropical lower stratosphere. These particles are most likely composed of nitric acid trihydrate (NAT). They were intermittently observed in a narrow layer above the tropopause (18±0.1 km) and over a broad geographic extent (>1100 km). In contrast to the background liquid sulfate aerosol, these particles are solid, much larger (1.7-4.7 µm vs. 0.1µm in diameter), and significantly less abundant (-4 cm-3 vs. 10 cm-3). Microphysical trajectory models suggest that the NAT particles grow over a 6-14 day period in supersaturated air that remains close to the tropical tropopause and might be a common feature in the tropics. The small number density of these particles implies a highly selective or slow nucleation process. Understanding the formation of solid NAT particles in the tropics could improve our understanding of stratospheric nucleation processes and, therefore, dehydration and denitrification. |
| Databáze: | Directory of Open Access Journals |
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