Quasi-biennial oscillation influence on long-period planetary
waves in the Antarctic upper mesosphere
Long-period planetary wave data derived from meteor wind observations recorded
over a 12-year period with the SuperDARN radar at Halley, Antarctica, are presented
and compared with the phase of the quasi-biennial oscillation (QBO) throughout the
equatorial stratosphere. Enhanced planetary wave activity in the Antarctic upper
mesosphere is found during the summer months, when the QBO in the equatorial upper
stratosphere is westerly, and during the late winter, when the QBO in the upper
stratosphere is easterly. These quasi-biennial enhancements in planetary wave activity
coincide with a reduction in strength, by up to 30%, of the late-winter eastward winds in
the Antarctic upper mesosphere. In addition, when the QBO is in the correct phase for
enhanced planetary wave activity in the upper mesosphere above Halley, planetary wave
activity measured in the upper mesosphere of the high-latitude Northern Hemisphere is
reduced (and vice versa). These results clearly indicate significant interhemispheric
propagation of planetary waves from the winter to summer hemispheres. Observational
evidence that the stratospheric QBO induces a strong enough QBO in the equatorial upper
mesosphere to act as a gate to the interhemispheric propagation of these long-period
waves is discussed in light of these results.
Details
Publication status:
Published
Author(s):
Authors: Hibbins, R.E. ORCID record for R.E. Hibbins, Jarvis, M.J., Ford, E.A.K.