Seasonal and latitudinal variations of the lower thermospheric tidal winds from meteor radar measurements in the U.S.S.R.

A long-term comparison of mesopause region wind measurements over Eastern and Central Europe

“…1), it can be concluded that the best correspondence is found between LF winds and the MR winds at 90-92 km altitude. Therefore, this altitude may be the height of maximum MR wind measurements, which is somewhat lower than the 93-95 km given by Lysenko et al (1992), and which is in good correspondence with the results presented by Merzlyakov and Portnyagin (1999). However, it cannot be excluded that the entire wind system is shifted in altitude even at a longitudinal distance of only 221.…”

Unexpectedly small semidiurnal tidal wind amplitudes in the mid-latitudemesopause region during September 2002

“…The September mean amplitudes are smaller than those measured at Collm in any year of observation since 1982. They are also smaller than those presented by other authors (Lysenko et al, 1992; for different years or different periods. The small v 12 have been accompanied by an unexpected early change of T 12 from its summer to winter position.…”

“…It can be seen that both the v 12 and T 12 values are outside of the range of previously measured values. Comparison with literature results (Lysenko et al, 1992;Manson et al, 1999) also show that none of the v 12 presented are as small as those measured at Collm in 2002. The prevailing winds fall in the range of previously measured wind values, but there is a weak indication that the zonal prevailing winds in the lower height range considered here is stronger than usual, while this is not the case in the upper height range.…”

“…The seasonal behaviour of the semidiurnal tidal (SDT) winds in the mesosphere/lower thermosphere (MLT) region around 80-100 km has been investigated using ground-based and space-based measurements (Lysenko et al, 1992;Burrage et al, 1995). Also, modelling of the seasonal variation has been performed using modified classical theory (Greisiger, 1975) and numerical models (Hagan et al, 1999;Manson et al, 1999).…”