We dedicate this paper to the memory of Walter Orr Roberts,
in Gratitude for his interest and encouragement of our work.
Summary
This paper summarizes the results of work which is based on the discovery by
Labitzke (1982,1987) of a
10-12-year oscillation in the arctic stratospheric temperature. The
oscillation modulates the extratropical effect of the Quasi-Biennial
Oscillation in winter and is in phase with the 11-year sunspot cycle.
Labitzke's original papers
dealt only with the north polar stratospheric temperature in winter, but we
have expanded the investigation to cover the whole year and most of the
Northern Hemisphere.
In months other than January, February and March, it is not necessary to group
the data according to the phase of the QBO to find the solar signal. The
signal appears as a
basic, consistent pattern in the
correlation between stratospheric
geopotential heights and the solar cycle in which the highest
correlations are south of about 45° N with a distinct
maximum over the western, ocean-covered
part of the hemisphere. The variation of the
stratospheric heights on the 10-12-year scale are - in the
area of high correlations
with the solar cycle - associated with temperature changes on the same time
scale in the middle and upper troposphere. Preliminary work suggests that the
interannual variation of the tropical and subtropical vertical motions
contains a component on the 10-12-year scale; but a mechanism which connects
the solar and tropospheric-stratospheric oscillations on the 10-12-year scale
has not yet been found.
In January and February the correlations of a full time series of
stratospheric quantities with the sun are smallest, although the basic
pattern is the same as during the rest of the year. The small size of the
correlation is due to the fact that they are of
opposite sign in the east and
west years of the Quasi-Biennial Oscillation. The correlation pattern
in the east years is the same as in the ten other months of the year; in the
west years the opposite sign is related to the fact that those
major midwinter breakdowns
of the stratospheric westerly (cyclonic) vortex which take place in the west
years, have so far happened only in maxima of the 11-year sunspot cycle.
References
Labitzke, K., 1987: Sunspots,
the QBO, and the stratospheric temperature in the north polar region. --
Geophys. Res. Lett., 14, 535-537. Labitzke, K.,
H. van Loon, 1992: Association between the 11-year solar cycle and the
atmosphere. Part V: Summer. -- J. Clim. 5, 240-251. Labitzke, K.,
H. van Loon, 1994: Connection between the troposphere and stratosphere on a
decadal scale. -- Tellus 46A, 275-286.
![[TTO Abb. 1a]](/labitzke/tto/tto1a.gif)
![[TTO Abb. 2]](/labitzke/tto/tto2.gif)
signal appears as a
basic, consistent pattern in the
correlation between stratospheric
geopotential heights and the solar cycle in which the highest
correlations are south of about 45° N with a distinct
maximum over the western, ocean-covered
part of the hemisphere. The variation of the
stratospheric heights on the 10-12-year scale are - in the
area of high correlations
with the solar cycle - associated with temperature changes on the same time
scale in the middle and upper troposphere. Preliminary work suggests that the
interannual variation of the tropical and subtropical vertical motions
![[TTO Abb. 1b]](/labitzke/tto/tto1b.gif)
contains a component on the 10-12-year scale; but a mechanism which connects
the solar and tropospheric-stratospheric oscillations on the 10-12-year scale
has not yet been found.![[TTO Abb. 7]](/labitzke/tto/tto7.gif)
opposite sign in the east and
west years of the Quasi-Biennial Oscillation. The correlation pattern
in the east years is the same as in the ten other months of the year; in the
west years the opposite sign is related to the fact that those
major midwinter breakdowns
of the stratospheric westerly (cyclonic) vortex which take place in the west
years, have so far happened only in maxima of the 11-year sunspot cycle.