Growth of nitric acid hydrates on thin sulfuric acid films
- Univ. of Colorado, Boulder, CO (United States)
Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 [times] 10[sup [minus]4] Torr H[sub 2]O and 1-2.5 [times] 10[sup [minus]6] Torr HNO[sub 3]) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO[sub 3]/H[sub 2]O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H[sub 2]SO[sub 4] films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.
- OSTI ID:
- 6795175
- Journal Information:
- Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 21:10; ISSN GPRLAJ; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
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