Seasonal and inter-annual variability of the quasi 2 day wave over Collm (51.3° N, 13° E) as obtained from VHF meteor radar measurements

[摘要] The quasi 2 day wave (QTDW) over Collm (51° N, 13° E) hasbeen studied between September 2004 and September 2013 using a VHF meteorradar. The 9 year mean amplitudes show a strong summer maximum withseveral irregular bursts and much weaker winter maxima. In summer, themeridional amplitude is slightly larger than the zonal one with about15 m s⁻¹ at 91 km height. Phase differences are slightly higherthan 90°, which indicates a polarization that is nearly circular. Onan average the QTDW is amplified after a maximum of zonal wind shear. Thiscan be realized in the summer mesospheric jet where the zonal wind componenthas its minimum or, in other words, the easterly jet maximizes. Thus,instability is found as a likely forcing mechanism. QTDW amplitudes exhibitconsiderable inter-annual variability. In particular, there is a possiblerelation between the QTDW amplitude and the 11-year solar cycle in winter butnot in summer.

[学科分类] 电子、光学、磁材料