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Hydrochloric acid and the chlorine budget of the lower statosphereConcentrations of HCl measurements in the lower stratosphere in 1993 by the ALIAS instrument on the ER-2 aircraft reveal that only 40% of inorganic chlorine (Cl(y), inferred from in situ measurements of organic chlorinated sources gases) is present as HCl, significantly lower than model predictions. Although the sum of measured HCl, ClO and ClONO2, the latter inferred from measurements of ClO and NO2 equals Cl(y) to within the incertainty of measurement, it is systematically less than Cl(y) by 30-50%. This discrepancy suggests that concentrations of ClONO2 may exceed those of HC; near 20 km altitude, consistent with a slower photolysis rate for ClONO2 than calculated using recommended cross sections. Comparison of profiles of HCl measured during 1992 and 1193 at mid-latitudes by balloon (BLISS and MARKIV), space shuttle (ATMOS), and satellite (HALOE) instruments with the aircraft data reveal an apparent pressure dependence to the HCl to Cl(y) ratio, consistent with a factor of 3-10 reduction in the photolysis rate for ClONO2 at ER-2 altitudes. However, the diurnal variation of ClO is well-simulated by models using the recommended photolysis rate, and simulations measurements of ClONO2 and HCl at mid-latitudes by ATMOS and MARKIV report HCl (HCL+ ClONO2) ratios greater than or equal to 50%. Premliminary measurements by ALIAS in the southern hemisphere report HCl/Cl(y) values of about 75%.
Document ID
19950046408
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Webster, C. R.
(Univ. of Colorado, Boulder, CO United States)
May, R. D.
(Univ. of Colorado, Boulder, CO United States)
Jaegle, L.
(NOAA, Boulder, CO United States)
Hu, H.
(Univ. of Colorado, Boulder, CO United States)
Sander, S. P.
(Univ. of Colorado, Boulder, CO United States)
Gunson, M. R.
(Univ. of Colorado, Boulder, CO United States)
Toon, G. C.
(Univ. of Colorado, Boulder, CO United States)
Russell, J. M., III
(National Center for Atmospheric Research, Boulder, CO United States)
Stimpfle, R. M.
(NASA Langley Research Center Hampton, VA, United States)
Koplow, J. P.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
November 15, 1994
Publication Information
Publication: Geophysical Research Letters
Volume: 21
Issue: 23
ISSN: 0094-8276
Subject Category
Geophysics
Accession Number
95A78007
Distribution Limits
Public
Copyright
Other

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