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In‐situ measurement of Cl 2 and O 3 in a stratospheric solid rocket motor exhaust plume
Author(s) -
Ross M. N.,
Ballenthin J. O.,
Gosselin R. B.,
Meads R. F.,
Zittel P. F.,
Benbrook J. R.,
Sheldon W. R.
Publication year - 1997
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 - 10.1029/97gl01592
Subject(s) - plume , ozone , atmospheric sciences , environmental science , stratosphere , daytime , panache , photometer , meteorology , physics , optics
The concentration of Cl 2 in the stratospheric exhaust plume of a Titan IV launch vehicle was measured with a neutral mass spectrometer carried on a WB‐57F aircraft at 18.9 km altitude. Twenty nine minutes after a twilight Titan IV launch, the mean Cl 2 concentration across an 8 km wide plume was 126 ± 44 ppbv, consistent with model predictions that a large fraction of the HCl in solid rocket motor exhaust is converted into Cl 2 by afterburning reactions in the hot plume. Co‐incident measurements with ultraviolet absorption photometers also carried on the aircraft show that ozone concentration in the plume was not different from ambient levels. This is consistent with model predictions that nighttime SRM launches will not cause transient ozone loss in the lower stratosphere. The measured Cl 2 concentration equals 15% of the ambient ozone concentration suggesting that transient ozone reduction in SRM plume wakes can be expected after daytime launches when solar ultraviolet radiation will photolyze the exhaust plume Cl 2 .