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Stratospheric denitrification due to polar aerosol formation: Implications for a future atmosphere with increased CO 2
Author(s) -
Pitari Giovanni,
Ricciardulli Lucrezia
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 - 10.1029/94gl01136
Subject(s) - stratosphere , atmospheric sciences , atmosphere (unit) , aerosol , polar vortex , polar , nitric acid , environmental science , denitrification , water vapor , atmospheric models , reactive nitrogen , atmospheric chemistry , nitrogen , ozone , chemistry , meteorology , inorganic chemistry , geology , physics , organic chemistry , astronomy
The amount of stratospheric denitrification produced by NAT aerosol formation is studied with a photochemical two‐dimensional model which includes the effects of zonal asymmetries of the temperature field. The model photochemistry is coupled with a microphysical code for aerosol formation and growth, so that the permanent loss of stratospheric nitric acid and water vapor may be taken into account. The model results for nitric acid relative to the atmospheric chemical composition of 1980 are compared with LIMS data. We show that the level of denitrification may rise substantially if the polar vortex cools down, as it could be the case in a future atmosphere richer in carbon dioxide. A three‐dimensional model is used to calculate the temperature perturbation due to an increase of CO 2 from 335 ppmv of 1980 (baseline) up to 500 ppmv (predicted for 2050). The photochemical model adopting these new temperatures predicts an average 20% HNO 3 column decrease poleward of 45N with respect to baseline. One consequence is that the relative weight of the NO x catalytic cycle for O 3 destruction decreases with respect to the present atmosphere.