The role of the QBO in the inter-hemispheric coupling of summer mesospheric temperatures
Journal article, Peer reviewed
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Date
2011Metadata
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- Institutt for fysikk [2646]
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Abstract
Inter-hemispheric coupling between the polar
summer mesosphere and planetary-wave activity in the extratropical
winter stratosphere has recently been inferred using
Polar Mesospheric Cloud (PMC) properties as a proxy
for mesospheric temperature (Karlsson et al., 2007). Here
we confirm these results using a ten-year time series of
July mesospheric temperatures near 60 N derived from the
hydroxyl (OH) nightglow. In addition, we show that the
time-lagged correlation between these summer mesospheric
temperatures and the ECMWF winter stratospheric temperatures
displays a strong Quasi-Biennial Oscillation (QBO).
The sign and phase of the correlation is consistent with the
QBO modulation of the extra-tropical stratospheric dynamics
in the Southern Hemisphere via the Holton-Tan mechanism
(Holton and Tan, 1980). This lends strength to the
identification of synoptic and planetary waves as the driver of
the inter-hemispheric coupling, and results in a strong QBO
modulation of the polar summer mesospheric temperatures.