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Composition and freezing of aqueous H 2 SO 4 /HNO 3 solutions under polar stratospheric conditions
Author(s) -
Beyer K. D.,
Seago S. W.,
Chang H. Y.,
Molina M. J.
Publication year - 1994
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/94gl00915
Subject(s) - stratosphere , aqueous solution , freezing point , sulfuric acid , polar , dew point , frost (temperature) , aerosol , analytical chemistry (journal) , chemistry , mineralogy , atmospheric sciences , meteorology , inorganic chemistry , environmental chemistry , thermodynamics , geology , organic chemistry , physics , astronomy
The results of laboratory investigations of the freezing behavior of aqueous acid solutions indicate that in the stratosphere H 2 SO 4 /H 2 O aerosol droplets would not freeze at temperatures above the ice frost point in the absence of HNO 3 ; however, in the presence of typical levels of HNO 3 liquid sulfuric acid aerosols take up significant amounts of HNO 3 and H 2 O vapors and freeze much more readily. This is a consequence of the very rapid change in composition of the liquid droplets as the temperature drops to within two to three degrees of the equilibrium temperature at which HNO 3 and H 2 O vapors would co‐condense to form a liquid solution. In the high latitude stratosphere this HNO 3 /H 2 O ‘dew point’ is typically around 192–194 K at 100 mbar.