The 8‐hour tide in the Arctic mesosphere and lower thermosphere

Abstract

[1] An all-sky VHF meteor radar at Esrange (68°N, 21°E) near Kiruna in Northern Sweden has been used to investigate the 8-hour tide in the Arctic mesosphere and lower thermosphere. We present a climatology of the 8-hour tide over the period October 1999 to April 2001. The tide appears to be a persistent feature of the Arctic atmosphere, although a large day-to-day variability of the tidal amplitude is observed. At times the 8-hour tide reaches amplitudes over 30 m s À1 . The amplitude of the tide increases with height across the observed height range of $80-100 km. Monthly mean tidal amplitudes range from <2 m sÀ1 to values as large as 10 m s À1 . A clear seasonal behavior is apparent with maximum amplitudes observed in the autumn. Vertical wavelengths are shortest in winter and spring (25-35 km) and longest in summer and autumn (50-90 km). At least on some occasions the vertical wave number relationships between the 8-, 12-, and 24-hour tides suggest that the 8-hour tide is being generated by nonlinear interaction between the 12-and 24-hour tides.

Observations of lunar tides in the mesosphere and lower thermosphere at Arctic and middle latitudes

“…The figure also shows a clear response at the period of the M 2 lunar tide. Note that the 6-h and 8-h tides over Esrange have been described elsewhere (Smith et al, 2004;Younger et al, 2002;Beldon et al, 2006). Figure 1b shows an expanded view of the periodogram of available spectral resolution).…”

Observations of OI 557.7 nm nightglow at Kolhapur (17° N), India

“…This is the first report of terdiurnal tides observed in the nightglow measurements over the Indian subcontinent. Many previous works have reported the observations of 8 h tide in the MLT region (for example, Glass and Fellons, 1975;Teitelbaum et al, 1989;Oznovich et al, 1995Oznovich et al, , 1997Thayaparan, 1997;Taylor et al, 1999;Smith, 2000;Younger et al, 2002;Taori et al, 2005;Wu et al, 2005;Beldon et al, 2006;Jiang et al, 2009;Rao et al, 2011). Glass and Fellons (1975) and Teitelbaum et al (1989) suggested that this wave can be interpreted both as the solar driven terdiurnal tide and as the result of nonlinear interaction between diurnal and semi-diurnal tides.…”

“…Smith (2000) reported the latitudinal structure and seasonal variation of the terdiurnal tides using the wind observations of HRDI instrument on-board UARS. Younger et al (2002) investigated the 8 h tidal phenomena Rao et al (2011) have reported the occurrence and variability of terdiurnal tides in the MLT region over Tiruneveli (8.7 • N, 77.8 • E), Koto Tabang (0.2 • S, 100.3 • E), and Pameungpeuk (7.4 • S, 107.4 • E) using meteor wind radar measurements. It is worthy to mention here that Tirunelveli is an equatorial station located within a distance of 9 • from Kolhapur -the site of current study.…”

Interhemispheric structure and variability of the 5-day planetary wave from meteor radar wind measurements

“…All of these radars are All-Sky Interferometric Meteor Radars (SkiYMet) (Hocking and Vandepeer, 2001). Details of the individual systems are provided by Mitchell et al (2002), Day and Mitchell (2010), and Sandford et al (2010) for the Esrange system, Singer et al (2003) and Hoffmann et al (2010) for the Juliusruh system, Fritts et al (2010Fritts et al ( , 2012 for the TdF system, and Younger et al (2002) and Mitchell and Beldon (2009) …”