TY - JOUR
T1 - Observation-based assessment of stratospheric fractional release, lifetimes, and ozone depletion potentials of ten important source gases
AU - Laube, J.C.
AU - Keil, A
AU - Bönisch, H.
AU - Engel, A.
AU - Roeckmann, T.
AU - Volk, C.M.
AU - Sturges, W.T.
PY - 2013
Y1 - 2013
N2 - Estimates of the recovery time of stratospheric
ozone heavily rely on the exact knowledge of the processes
that lead to the decomposition of the relevant halogenated
source gases. Crucial parameters in this context are fractional
release factors (FRFs) as well as stratospheric lifetimes
and ozone depletion potentials (ODPs).We here present data
from the analysis of air samples collected between 2009 and
2011 on board research aircraft flying in the mid- and highlatitude
stratosphere and infer the above-mentioned parameters
for ten major source gases: CFCl3 (CFC-11), CF2Cl2
(CFC-12), CF2ClCFCl2 (CFC-113), CCl4 (carbon tetrachloride),
CH3CCl3 (methyl chloroform), CHF2Cl (HCFC-
22), CH3CFCl2 (HCFC-141b), CH3CF2Cl (HCFC-142b),
CF2ClBr (H-1211), and CF3Br (H-1301). The inferred correlations
of their FRFs with mean ages of air reveal less decomposition
as compared to previous studies for most compounds.
When using the calculated set of FRFs to infer equivalent
stratospheric chlorine, we find a reduction of more than
20% as compared to the values inferred in the most recent
Scientific Assessment of Ozone Depletion by the World Meteorological
Organisation (WMO, 2011). We also note that
FRFs and their correlations with mean age are not generally
time-independent as often assumed. The stratospheric
lifetimes were calculated relative to that of CFC-11. Within
our uncertainties the ratios between stratospheric lifetimes
inferred here agree with the values in recent WMO reports
except for CFC-11, CFC-12 and CH3CCl3. Finally, we calculate
lower ODPs than recommended by WMO for six out of
ten compounds, with changes most pronounced for the three
HCFCs. Collectively these newly calculated values may have
important implications for the severity and recovery time of
stratospheric ozone loss.
AB - Estimates of the recovery time of stratospheric
ozone heavily rely on the exact knowledge of the processes
that lead to the decomposition of the relevant halogenated
source gases. Crucial parameters in this context are fractional
release factors (FRFs) as well as stratospheric lifetimes
and ozone depletion potentials (ODPs).We here present data
from the analysis of air samples collected between 2009 and
2011 on board research aircraft flying in the mid- and highlatitude
stratosphere and infer the above-mentioned parameters
for ten major source gases: CFCl3 (CFC-11), CF2Cl2
(CFC-12), CF2ClCFCl2 (CFC-113), CCl4 (carbon tetrachloride),
CH3CCl3 (methyl chloroform), CHF2Cl (HCFC-
22), CH3CFCl2 (HCFC-141b), CH3CF2Cl (HCFC-142b),
CF2ClBr (H-1211), and CF3Br (H-1301). The inferred correlations
of their FRFs with mean ages of air reveal less decomposition
as compared to previous studies for most compounds.
When using the calculated set of FRFs to infer equivalent
stratospheric chlorine, we find a reduction of more than
20% as compared to the values inferred in the most recent
Scientific Assessment of Ozone Depletion by the World Meteorological
Organisation (WMO, 2011). We also note that
FRFs and their correlations with mean age are not generally
time-independent as often assumed. The stratospheric
lifetimes were calculated relative to that of CFC-11. Within
our uncertainties the ratios between stratospheric lifetimes
inferred here agree with the values in recent WMO reports
except for CFC-11, CFC-12 and CH3CCl3. Finally, we calculate
lower ODPs than recommended by WMO for six out of
ten compounds, with changes most pronounced for the three
HCFCs. Collectively these newly calculated values may have
important implications for the severity and recovery time of
stratospheric ozone loss.
U2 - 10.5194/acp-13-2779-2013
DO - 10.5194/acp-13-2779-2013
M3 - Article
SN - 1680-7316
VL - 13
SP - 2779
EP - 2791
JO - Atmospheric chemistry and physics
JF - Atmospheric chemistry and physics
ER -