Varotsos (2002a,b), suggested that both the smaller-sized ozone hole
over Antarctica and its splitting in two holes in September 2002
occurred due to an unprecedented major sudden stratospheric warming
caused by very strong planetary waves propagated in the southern
hemisphere. Subsequently, a NASA press release of December 6,
2002, also reported the prevalence of very strong planetary waves
in Antarctica.
The aim of this Letter is to further discuss the morphology of the
Antarctic ozone hole, to detect the causes that allowed the Antarctic
stratosphere to exhibit this exceptional warming and to examine
what it denotes about its mechanisms.
Concerning the morphology, among the principal findings is that
the ozone hole split occurred not only in the stratosphere but extended
in the lower altitudes (upper troposphere).
As to the causes of the major sudden stratospheric warming of 2002, a
comparison with the previous warmings in Antarctica since 1964 is
made. The smaller-sized Antarctic ozone hole of 2002 is approximately
equal to that of 1988 when a strong sudden stratospheric warming
occurred. If only the destruction of ozone by chlorofluorocarbons resulted
in the delayed sudden stratospheric warmings in Antarctica, then
the early sudden stratospheric warmings of 1988 and 2002 would not
have occurred, since chlorofluorocarbon loading of the stratosphere
has remained relatively stable in recent years. Furthermore, it appears
that the El Nino characteristics in 1988 and 2002 are not similar. |
