In january and february the correlations with the sunspot cycle are smallest. The smallness of the correlations is owing to the fact that they are different in the east and west years of the quasi-biennial oscillation in the equatorial stratospheric winds. The correlation pattern in the east years is the same as in the other seasons and is statistically significant. In west years the correlations are insignificant outside the arctic, and the correlation in the arctic in these years is related to the fact that major midwinter breakdowns of the cyclonic vortex in the west years so far have happened only at maxima in the solar cycle.
Until recently reliable continuous
series of analyses of the stratosphere
were not available for the southern
hemisphere. The U.S. National Centers
for Environmental Prediction and the
National Center for Atmospheric Research
have now, however, issued a 23-year
series of the re-analyzed global data
which has made it possible to detect the
solar signal on the southern hemisphere.
It turns out to be almost the same as
that on the northern hemisphere.
The correlations between total
column ozone and the sunspot cycle are
lowest in the equtorial regions, where
ozone is produced, and in the subpolar
regions, where the largest amounts are
found. In the annual mean the largest
correlations lie between 5° and
30° latitude. We suggest that this distribution
of correlations is due to the fact that
the subtropical heights of the
constant-pressure surfaces in the ozone
layer are higher in maximum than in
minimum years of the sunspot cycle, and
that the higher subtropical heights in
the solar maxima depress the poleward
transport of ozone through the subtropics
and thus create an abundance of ozone.