Laboratory simulations of PSC particle formation
- Univ. of Minnesota, Minneapolis (United States)
Recent observations of type I polar stratospheric cloud particles (PSC I) reveal some discrepancies with data on nitric acid trihydrate (NAT) obtained in laboratory studies. To better understand the in situ growth of PSC I particles, this experiment condensed mixtures of water and nitric acid vapor at temperatures and pressures which approximated those of the polar stratosphere more closely than in prior studies. Mono-, di-, and trihydrates of nitric acid were observed in solids condensed from vapor mixtures relatively rich in HNO[sub 3]. Solids formed under conditions that approached stratospheric contained significantly less HNO[sub 3] than the 25 mol% expected of NAT; the composition appeared to slowly change toward that of NAT over about ten hours. Solids with low HNO[sub 3] content showed HNO[sub 3] vapor pressures that were often highly supersaturated with respect to NAT. These results may help explain recent arctic PSC observations as those of relatively young clouds whose condensed materials have not yet reached equilibrium. 15 refs., 4 figs.
- OSTI ID:
- 6533002
- Journal Information:
- Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 20:5; ISSN GPRLAJ; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
CLOUDS
CRYOSPHERE
DISPERSIONS
EARTH ATMOSPHERE
EQUILIBRIUM
HYDRATES
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MIXTURES
NITRIC ACID
OXYGEN COMPOUNDS
PARTICLES
PHYSICAL PROPERTIES
POLAR REGIONS
SIMULATION
SOLIDS
STRATOSPHERE
THERMODYNAMIC PROPERTIES
VAPOR CONDENSATION
VAPOR PRESSURE
WATER