Institute for Atmospheric and Climate Science

U. K. Krieger et al., GRL 27, 2097 (2000)

Polar stratospheric clouds (PSCk) are important for the chemical activation of chlorine compounds and subsequent ozone depletion. However, how solid PSCs form is still subject to controversial discussion.  Recently, the octahydrate of sulfuric acid (H2S04·8H2O) has been proposed as a solid phase for PSC particles. In our experiment single H2SO4/H2O aerosols levitated in an electrodynamic balance are cooled to 158 k along the ice-liquid equilibrium line. This coexistence curve has been measured for the first time in the temperature interval between 200 K and 158 K. Three independent methods are used for measuring the H2SO4 concentration of the aerosol. No phase transition is observed over a time period of 24 hours and longer at these or higher temperatures. There is no indication for the occurrence of the octahydrate in our experiments. Since the product of experimental volume and suspension time is equal to that of stratospheric droplets over an entire winter, the homogeneous formation of octahydrate at quasi-equilibrium can be practically excluded.


Wichtiger Hinweis:
Diese Website wird in älteren Versionen von Netscape ohne graphische Elemente dargestellt. Die Funktionalität der Website ist aber trotzdem gewährleistet. Wenn Sie diese Website regelmässig benutzen, empfehlen wir Ihnen, auf Ihrem Computer einen aktuellen Browser zu installieren. Weitere Informationen finden Sie auf
folgender Seite.

Important Note:
The content in this site is accessible to any browser or Internet device, however, some graphics will display correctly only in the newer versions of Netscape. To get the most out of our site we suggest you upgrade to a newer browser.
More information

© 2015 ETH Zurich | Imprint | Disclaimer | 10 February 2007