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On the formation and sedimentation of stratospheric nitric acid aerosols: Implications for polar ozone destruction
Author(s) -
Arnold F.,
Petzoldt K.,
Reimer E.
Publication year - 1992
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 - 10.1029/92gl00652
Subject(s) - nitric acid , stratosphere , ozone , aerosol , ozone depletion , nucleation , atmospheric sciences , cloud condensation nuclei , polar , chemistry , atmospheric chemistry , meteorology , inorganic chemistry , geology , physics , organic chemistry , astronomy
The formation and sedimentation of nitric acid‐aerosols (NA‐aerosols) in the winter polar stratosphere is investigated in the light of recent mass spectrometric in‐situ measurements of gaseous nitric acid performed in the winter arctic stratosphere. We revisit the nitric acid measurements and extend their interpretation by carrying out isentropic trajectory calculations of the airmasses encountered in these experiments and by considering aerosol measurements, which became available recently. Our analysis shows that the mass spectrometer measurements provide strong evidence for nitric acid nucleation and vertical redistribution of nitric acid due to sedimentation of HNO 3 ‐containing aerosols. Both these processes promote halogen‐catalysed destruction of ozone. Moreover, it is concluded that nitric acid nucleation is less efficient than expected from simple equilibrium considerations. Probably, this is due to rapid cooling and inefficient nucleation (inefficient activation of preexisting H 2 SO 4 /H 2 O‐aerosols for HNO 3 /H 2 O‐condensation) allowing only a small fraction of the preexisting H 2 SO 4 /H 2 O‐aerosols to serve as active nuclei.