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Vapor pressures of solid hydrates of nitric acid: Implications for polar stratospheric clouds

Journal Article · · Science (Washington, D.C.); (United States)
;  [1]; ;  [2]
  1. Aerodyne Research, Inc., Billerica, MA (United States)
  2. Harvard Univ., Cambridge, MA (United States)

Thermodynamic data are presented for hydrates of nitric acid: HNO[sub 3][center dot]H[sub 2]O, HNO[sub 3][center dot]2H[sub 2]O, HNO[sub 3][center dot]3H[sub 2]O, and a higher hydrate. Laboratory data indicate that nucleation and persistence of metastable HNO[sub 3][center dot]2H[sub 2]O may be favored in polar stratospheric clouds over the slightly more stable HNO[sub 3][center dot]3H[sub 2]O. Atmospheric observations indicate that some polar stratospheric clouds may be composed of HNO[sub 3][center dot]2H[sub 2]O and HNO[sub 3][center dot]3H[sub 2]O. Vapor transfer from HNO[sub 3][center dot]2H[sub 2]O to HNO[sub 3][center dot]3H[sub 2]O could be a key step in the sedimentation of HNO[sub 3], which plays an important role in the depletion of polar ozone.

OSTI ID:
6919452
Journal Information:
Science (Washington, D.C.); (United States), Journal Name: Science (Washington, D.C.); (United States) Vol. 259:5091; ISSN SCIEAS; ISSN 0036-8075
Country of Publication:
United States
Language:
English