A global inventory of stratospheric chlorine in 2004
Journal article, 2006
Total chlorine (CITOT) 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°-82°N, 30°-60°N, 30°S-30°N, 30°-60°S, and 60°-82°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 ClTOT values of 3.65 ppbv were determined for both the northern and southern midlatitudes (with an estimated 1σ, accuracy of ±0.13 ppbv and a precision of ±.09 ppbv), accompanied by a slightly lower value in the tropics and slightly higher values at high latitudes. Stratospheric ClTOT 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.
Author
R. Nassar
Harvard University
University of Waterloo
P. F. Bernath
University of Waterloo
C. D. Boone
University of Waterloo
C. Clerbaux
Pierre and Marie Curie University (UPMC)
Université libre de Bruxelles (ULB)
P. F. Coheur
Université libre de Bruxelles (ULB)
G. Dufour
University Paris-Saclay
L. Froidevaux
Jet Propulsion Laboratory, California Institute of Technology
E. Mahieu
University of Liège
J. C. McConnell
York University
S. D. McLeod
University of Waterloo
Donal Murtagh
Chalmers, Department of Radio and Space Science
C. P. Rinsland
NASA Langley Research Center
K. Semeniuk
York University
R. Skelton
University of Waterloo
K. A. Walker
University of Toronto
University of Waterloo
R. Zander
University of Liège
Journal of Geophysical Research
01480227 (ISSN) 21562202 (eISSN)
Vol. 111 22 D22312Subject Categories
Aerospace Engineering
DOI
10.1029/2006JD007073