Melting of H{sub 2}SO{sub 4}{center_dot}4H{sub 2}O particles upon cooling: Implications for polar stratospheric clouds
- Max Planck Institute for Chemistry, Mainz (Germany)
Polar stratospheric clouds (PSCs) are important for the chemical activation chlorine compounds and subsequent ozone depletion. Solid PSCs can form on sulfuric acid tetrahydrate (SAT) (H{sub 2}SO{sub 4}{center_dot}4H{sub 2}O) nuclei, but recent laboratory experiments have shown that PSC nucleation on SAT is strongly hindered. A PSC formation mechanism is proposed in which SAT particles melt upon cooling in the presence of HNO{sub 3} to form liquid HNO{sub 3}-H{sub 2}SO{sub 4}-H{sub 2}O droplets 2 to 3 kelvin above the ice frost point. This mechanism offers a PSC formation temperature that is defined by the ambient conditions and sets a temperature limit below which PSCs should form. 20 refs., 4 figs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 426165
- Journal Information:
- Science, Journal Name: Science Journal Issue: 5268 Vol. 272; ISSN SCIEAS; ISSN 0036-8075
- Country of Publication:
- United States
- Language:
- English
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