Laboratory studies of polar stratospheric cloud formation
- Univ. of Colorado, Boulder, CO (United States)
Polar stratospheric clouds (PSCs) are generally classified as type I or type II, depending on their formation temperature. Type II PSCs form at stratospheric temperatures near 189 K and are composed of water ice. Type I PSCs are stable at warmer temperatures and contain both nitric acid and water. Because nitric acid trihydrate (NAT) is the thermodynamically stable form of HNO{sub 3}/H{sub 2}O under stratospheric conditions, it has often been assumed that type I PSCs are composed of NAT. Recent measurements, however, suggest that NAT may not form readily in the stratosphere due to a kinetic barrier. Type I PSCs are believed to nucleate on preexisting stratospheric sulfate aerosols composed of sulfuric acid and water. We are performing laboratory experiments to measure the nucleation and growth of type I PSCs on sulfuric acid. We study both thin film samples modeling stratospheric particles and actual aerosol samples generated in the laboratory. The results of these studies will be discussed in the context of current theories for type I PSC formation.
- OSTI ID:
- 215125
- Report Number(s):
- CONF-950801--
- Country of Publication:
- United States
- Language:
- English
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