A global inventory of stratospheric chlorine in 2004

R. Nassar, P. F. Bernath, C. D. Boone, C. Clerbaux, P. F. Coheur, G. Dufour, L. Froidevaux, E. Mahieu, J. C. McConnell, S. D. McLeod, D. P. Murtagh, C. P. Rinsland, K. Semeniuk, R. Skelton, K. A. Walker, R. Zander

Research output: Contribution to journalArticlepeer-review

Abstract

[1] Total chlorine (Cl-TOT) in the stratosphere has been determined using the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements of HCl, ClONO2, CH3Cl, CCl4, CCl3F (CFC-11), CCl2F2 (CFC-12), CHClF2 (HCFC-22), CCl2FCClF2 (CFC-113), CH3CClF2 (HCFC-142b), COClF, and ClO supplemented by data from several other sources, including both measurements and models. Separate chlorine inventories were carried out in five latitude zones (60 degrees - 82 degrees N, 30 degrees - 60 degrees N, 30 degrees S - 30 degrees N, 30 degrees - 60 degrees S, and 60 degrees - 82 degrees S), averaging the period of February 2004 to January 2005 inclusive, when possible, to deal with seasonal variations. The effect of diurnal variation was avoided by only using measurements taken at local sunset. Mean stratospheric Cl-TOT values of 3.65 ppbv were determined for both the northern and southern midlatitudes (with an estimated 1 sigma accuracy of +/- 0.13 ppbv and a precision of +/- 0.09 ppbv), accompanied by a slightly lower value in the tropics and slightly higher values at high latitudes. Stratospheric Cl-TOT profiles in all five latitude zones are nearly linear with a slight positive slope in ppbv/km. Both the observed slopes and pattern of latitudinal variation can be interpreted as evidence of the beginning of a decline in global stratospheric chlorine, which is qualitatively consistent with the mean stratospheric circulation pattern and time lag necessary for transport.

Original languageEnglish
Pages (from-to)-
Number of pages13
JournalJournal of Geophysical Research
Volume111
Issue numberD22
DOIs
Publication statusPublished - 30 Nov 2006

Keywords

  • HALOGEN OCCULTATION EXPERIMENT
  • OZONE DEPLETION
  • SELF-REACTION
  • BUDGET
  • VALIDATION
  • SATELLITE
  • CLO
  • CONFIRMATION
  • TEMPERATURE
  • HALOCARBONS

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