Formation of polar stratospheric clouds on preactivated background aerosols
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Results of laboratory simulations of the growth of nitric acid trihydrate, HNO33H2O, on sulfuric acid tetrahydrate, H2SO44H2O, are presented. The observations reveal that under typical stratospheric conditions uptake of HNO3 on a H2SO44H2O substrate results in a surface coverage of approximately one monolayer or less, and that initial HNO33H2O nucleation requires a large supersaturation. We also observe that a H2SO44H2O substrate, onto which a HNO33H2O film has been deposited and subsequently evaporated, exhibits a remarkable enhancement in its nucleation ability for this nitric acid hydrate. In the stratosphere, PSC particles may experience repeated cycles of evaporation and condensation of HNO3 on preexisting background frozen sulfate aerosols. Hence, growth of HNO33H2O on preactivated aerosols provides one important mechanism for polar stratospheric cloud formation and denitrification. Copyright 1996 by the American Geophysical Union.
Geophysical Research Letters
author list (cited authors)
Zhang, R., Leu, M., & Molina, M. J.
complete list of authors
Zhang, Renyi||Leu, Ming-Taun||Molina, Mario J