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The upper mesospheric neutral winds and temperatures have been derived from continuous meteor radar (MR) measurements over Sodankyla, Finland, in 2008-2014. Under conditions of low solar activity pronounced sudden mesospheric coolings linked to the major stratospheric warming (SSW) in 2009 and a medium SSW in 2010 are observed while there is no observed thermal signature of the major SSW in 2013 occurred during the solar maximum. Mesosphere-ionosphere anomalies observed simultaneously by the MR, the Aura satellite, and the rapid-run ionosonde during a period of major SSW include the following features. The mesospheric temperature minimum occurs 1 day ahead of the stratospheric maximum, and the mesospheric cooling is almost of the same value as the stratospheric warming (~50 K), the former decay faster than the latter. In the course of SSW, a strong mesospheric wind shear of ~70 m/s/km occurs. The wind turns clockwise (anticlockwise) from north-eastward (south-eastward) to south-westward (north-westward) above (below) 90 km. As the mesospheric temperature reaches its minimum, the gravity waves (GW) in the ionosphere with periods of 10-60 min decay abruptly while the GWs with longer periods are not affected. The effect is explained by selective filtering and/or increased turbulence near the mesopause.
Original language | English |
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Pages (from-to) | 5226-5240 |
Number of pages | 15 |
Journal | Journal of Geophysical Research: Space Physics |
Volume | 120 |
Issue number | 6 |
DOIs | |
State | Published - 1 Jun 2015 |
ID: 36800770