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This paper is focused on the nonmigrating tidal activity seen in the SABER/TIMED temperatures that is related to the major sudden stratospheric warming (SSW) taking place in the Arctic winter of 2003/2004. The emphasis is on the nonmigrating diurnal tides observed in the stratosphere and lower mesosphere which is usually accepted to be insignificant in comparison with that in the upper mesosphere and thermosphere. By using different independent spectral methods we found a significant amplification in December–January of the following nonmigrating 24-h tides: zonally symmetric (s=0), eastward propagating with zonal wavenumber 1 (E1), and westward propagating with zonal wavenumbers 2 and 3 (W2 and W3) tides. It has been found that the double peak nonmigrating tidal amplifications located in the stratosphere (~40 km) and in the lower mesosphere (~70 km) are a consequence of the maintained hydrostatic relation. By detailed comparison of the evolution and spatial structure of the nonmigrating diurnal tides with those of the migrating diurnal tide and stationary planetary waves (SPWs) evidence for a SPW-migrating tide interaction as a source of nonmigrating tides has been presented. Therefore, the nonmigrating 24-h tides turn out to be an important component of the middle atmosphere dynamics during the major SSW in the Arctic winter of 2003/2004.

The present paper is focused on the global spatial (altitude and latitude) structure, seasonal and interannual variability of the migrating semidiurnal tide derived from the SABER/TIMED temperature measurements for 6 years (January 2002–December 2007). The tidal results are obtained by a new analysis method where the tides (migrating and nonmigrating) and the planetary waves (zonally travelling and stationary) are simultaneously extracted from the satellite data. The strongest migrating semidiurnal tide has been derived at tropical latitudes (±20–30°) where it revealed significant amplification between May and August in the lower thermosphere of both hemispheres. On the average, the semidiurnal temperature tide is stronger in the SH (32 K) than that in the NH (30 K) and the tidal amplitudes at 110 km height are nearly a factor of 5 larger than those at 90 km. The migrating semidiurnal tide in both hemispheres revealed remarkable seasonal behavior at the altitude where it maximizes, ~110 km in the NH and ~115 km in the SH, indicating repeatable each year maxima exactly in May–June and August. However, while the main maximum in the NH is that in August, in the SH it is that in May. The vertical wavelengths indicated seasonal variability being larger in summer (~38–50 km) than in winter (~25–35 km). The seasonal behavior of the semidiurnal tide in the middle latitudes (±40°) is dominated by annual variability with a winter maximum in the upper mesosphere (90 km) of both hemispheres and summer one in the lower thermosphere (110 km). The NH summer maximum (June and August peaks) is much stronger than that in the SH (November and March peaks) having amplitudes of ~23 K and ~13–15 K respectively. The vertical wavelengths at both hemispheres indicated slight seasonal changes and a mean vertical wavelength of ~35 km is observed during most of the year. The interannual variability of the semidiurnal tide in the midlatitude lower thermosphere is at least partly connected with the stratospheric QBO as this effect is stronger in the NH.

This short-communication presents a new method for assessing the amplitude modulation of the stationary planetary waves (SPWs). The suggested procedure allows estimating the contribution of the amplitude modulated SPWs to the field of the zonally travelling planetary waves. The root of the method consists in calculating of a quantity that is analogous to 2-D Lomb-Scargle amplitude spectrum and also the relative error of the approximation. The amplitude "spectra" of the SPWs give information about the period(s) of modulation, while the relative errors - define the coefficient(s) of modulation. The suggested method is applied to the UKMO temperature data for the Arctic winter of 2004–2005.

The coupling of the dynamical regimes in the high- and low-latitude stratosphere and mesosphere during the major SSW in the Arctic winter of 2003/2004 has been studied. The UKMO zonal wind data were used to explore the latitudinal coupling in the stratosphere, while the coupling in the mesosphere was investigated by neutral wind measurements from eleven radars situated at high, high-middle and tropical latitudes. It was found that the inverse relationship between the variability of the zonal mean flows at high- and low-latitude stratosphere related to the SSW is produced by global-scale zonally symmetric waves. Their origin and other main features have been investigated in detail. Similar latitudinal dynamical coupling has been found for the mesosphere as well. Indirect evidence for the presence of zonally symmetric waves in the mesosphere has been found.