Monitoring of the stratospheric chlorine activation by Global Ozone Monitoring Experiment (GOME) OClO measurements in the austral and boreal winters 1995 through 1999
T. Wagner et al., Monitoring of the stratospheric chlorine activation by Global Ozone Monitoring Experiment (GOME) OClO measurements in the austral and boreal winters 1995 through 1999, J GEO RES-A, 106(D5), 2001, pp. 4971-4986
Measurements of OClO total column amounts by means of the Global Ozone Moni
toring Experiment (GOME) instrument conducted in the austral and boreal win
ter stratospheres from 1995 through 1999 are presented. GOME is a four-chan
nel UV/visible spectrometer (240-790 nm) deployed on the polar orbiting Eur
opean ERS-2 satellite since April 1995. Previous studies have shown that th
e observations of OClO, the symmetric chlorine dioxide formed in a side cha
nnel of the reaction of BrO + ClO, can serve as an indicator for a stratosp
heric chlorine activation. GOME's 3-day coverage of the global atmosphere a
llows us to infer the first global data set of OClO, and to study continuou
s time series of its occurrence in both winter stratospheres. It is found t
hat, while OClO regularly occurs over Antarctica in similar amounts and sea
sonal timing during the different winters, its occurrence is much more vari
able in the Arctic winter stratosphere, primarily because of the larger dyn
amic activity that result in warmer temperatures there. About 40% higher OC
lO column amounts are found in the Antarctic polar stratosphere than in its
northern counterpart, a further indication for a significantly more effici
ent chlorine activation in the Antarctic than the Arctic late winter and sp
ring stratosphere.