Modified Lagrangian-mean diagnostic applied to the polar vortex evolution
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Yoshihiro Tomikawa
National Institute of Polar Research
Kaga 1-9-10, Itabashi-ku, Tokyo 173-8515, Japan
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E-mail:
tomikawa@nipr.ac.jp
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The modified Lagrangian-mean diagnostic makes it possible to
separate nonconservative from conservative effects on the
atmospheric circulation.
We further divided the nonconservative effects into diabatic
and frictional parts, and applied this diagnostic to the NH/SH
polar vortex evolution.
Our analysis quantitatively clarified the importance of diabatic
(mostly radiative) effect throughout the polar vortex evolution,
usually masked by transient wave-mean flow interaction
in the conventional Eulerian-mean framework.
It is also discussed to what extent the gravity wave drag contributes
to the systematic change of the polar vortex.