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Infrared measurements of atmospheric CH 3 CN
Author(s) -
Kleinböhl Armin,
Toon Geoffrey C.,
Sen Bhaswar,
Blavier JeanFrançois L.,
Weisenstein Debra K.,
Wennberg Paul O.
Publication year - 2005
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 - 10.1029/2005gl024283
Subject(s) - stratosphere , mixing ratio , occultation , tropopause , altitude (triangle) , atmospheric sciences , atmosphere (unit) , infrared , latitude , environmental science , physics , analytical chemistry (journal) , astrophysics , chemistry , meteorology , optics , astronomy , geometry , mathematics , chromatography
For the first time CH 3 CN has been measured in the Earth's atmosphere by means of infrared remote sensing. Vertical profiles of volume mixing ratio were retrieved from 12 solar occultation measurements by the balloon‐borne JPL MkIV interferometer between 1993 and 2004. Profile retrieval is possible in an altitude range between 12 and 30 km with a precision of ∼20 ppt in the Arctic and ∼30 ppt at mid‐latitudes. The retrieved CH 3 CN profiles show mixing ratios of 100–150 ppt a few kilometers above the tropopause that decrease to values below 40 ppt at altitudes between 22 and 30 km. The CH 3 CN mixing ratios show a reasonably compact correlation with the stratospheric tracers CH 3 Cl and CH 4 . The CH 3 CN altitude profiles and tracer correlations are well reproduced by a 2‐dimensional model, suggesting that CH 3 CN is long‐lived in the lower stratosphere and that previously‐proposed ion‐molecule reactions do not play a major role as loss processes of CH 3 CN.