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Laboratory studies of the nitric acid trihydrate: Implications for the south polar stratosphere
Author(s) -
Hanson David,
Mauersberger Konrad
Publication year - 1988
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/gl015i008p00855
Subject(s) - stratosphere , nitric acid , polar , atmosphere (unit) , water vapor , vapor pressure , analytical chemistry (journal) , mixing ratio , partial pressure , mineralogy , materials science , chemistry , atmospheric sciences , inorganic chemistry , meteorology , geology , environmental chemistry , oxygen , physics , organic chemistry , astronomy
Vapor pressures of HNO 3 and H 2 O have been measured over the trihydrate crystal, formed by vapor deposit on a glass surface. In the temperature range 190 K to 205 K the two phase‐equilibrium trihydrate/vapor was studied by adding and removing H 2 O. Coexistence equilibria vapor pressures of trihydrate/solid solutions of HNO 3 in ice (‘ice’) and of mono‐/trihydrate were also measured. Results show that for typical mixing ratios of H 2 O and HNO 3 found in the lower stratosphere (3 ppm H 2 O, 5 ppb HNO 3 ) the trihydrate would start to form at temperatures about 7 K higher than the ice point. The pressure of atmospheric HNO 3 would rapidly decrease as the atmosphere cools without large changes in partial pressures of H 2 O. These laboratory results provide information on the formation of polar stratospheric clouds containing H 2 O and HNO 3 .