Premium
Perturbation of stratospheric nitrogen dioxide by volcanic aerosol in the Arctic
Author(s) -
Lateltin E.,
Pommereau J.P.,
Le Texier H.,
Pirre M.,
Ramaroson R. A.
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 - 10.1029/93gl00591
Subject(s) - aerosol , nitrogen dioxide , atmospheric sciences , volcano , stratosphere , isentropic process , sulfuric acid , atmospheric chemistry , volcanic gases , saturation (graph theory) , nox , nitrogen , trace gas , sulfate aerosol , environmental science , chemistry , meteorology , ozone , geology , thermodynamics , inorganic chemistry , physics , combustion , mathematics , organic chemistry , combinatorics , seismology
NO 2 vertical profiles observed from balloon borne UV‐visible spectrometers during EASOE were simulated in order to quantify the NOx depletion by volcanic aerosol. Calculations were performed with a box photochemical model integrated along isentropic trajectories at 6 potential temperature levels (350, 380, 400, 475, 550 and 700 K), and initialized as far as possible from experimental data and from 2D model zonal averages, when not available. NO 2 vertical profiles are well captured by the model including current gas phase and heterogeneous chemistry. The very low NO 2 concentrations reported during the coldest and darkest part of the winter might be reproduced by gas phase chemistry alone. They are largely due to the lack of sunlight. Otherwise, in fall and spring at warmer temperature, NO 2 concentrations are significantly lower than that simulated in pure gas phase chemistry. The depletion is due to the presence of volcanic aerosols. The responsible reaction is the heterogeneous conversion of N 2 O 5 into nitric acid on sulfuric acid droplets. Sunlight attenuation by the aerosol layer contributes for a minor part only. The role of the conversion of ClONO 2 is negligible. However, NO 2 cannot be totally removed by the heterogeneous conversion of N 2 O 5 on aerosol. There is a saturation effect which originates in the slow gas phase conversion of NO 2 into N 2 O 5 . The NO 2 concentration at saturation is then mostly controlled by temperature.