MF radar observations of terdiurnal tide in the mesosphere and lower thermosphere at Wakkanai , Japan

The 8-h tide in the mesosphere and lower thermosphere over Maui (20.75° N, 156.43° W)

“…For example, regular annual variation of the wave phase was observed in the meridional wind at Wuhan (30 • N) and Wakkanai (45.4 • N) (Namboothiri et al, 2004;Zhao et al, 2005), and in the zonal wind at London, Canada (43 • N) (Thayaparan, 1997). The vertical wavelength reported by the previous studies was found to vary widely, over a range from 12 to more than 1000 km.…”

“…The vertical wavelength reported by the previous studies was found to vary widely, over a range from 12 to more than 1000 km. At high-latitude, 68 • N, the vertical wavelength was from 31 km to 91 km (Younger et al, 2002); at mid-latitudes, ∼43-52 • N, the vertical wavelength varied in a large range from 22 to ≥1000 km (Thayaparan, 1997;Namboothiri et al, 2004); and at the low latitude of 22 • S shorter vertical wavelengths ∼12-32 km in the meridional wind were reported by Tokumoto et al (2007).…”

“…The features and seasonal variabilities of the diurnal tide and semidiurnal tide in the mesosphere and lower thermosphere (MLT) have been quite well investigated through observations and model simulations (Manson and Meek, 1986;Teitelbaum et al, 1989;Thayaparan, 1997;Pendleton et al, 2000;Smith, 2000;Smith and Ortland, 2001;Akmaev, 2001;Younger et al, 2002;Batista et al, 2004;Namboothiri et Correspondence to: G. Jiang (gyjiang@spaceweather.ac.cn) al., 2004;Taori et al, 2005;Zhao et al, 2005;Beldon et al, 2006;Tokumoto et al, 2007). Nevertheless, the 8-h tide, as a distinct wave signature in the MLT region, is not well understood, especially compared to the diurnal tide and semidiurnal tide.…”

“…Nevertheless, the 8-h tide, as a distinct wave signature in the MLT region, is not well understood, especially compared to the diurnal tide and semidiurnal tide. Besides the work of Smith (2000) based on the wind measurement of High Resolution Doppler Interferometer (HRDI) instrument on the Upper Atmosphere Research Satellite (UARS), the variations of the 8-h tide have been investigated using ground-based observations in the Northern Hemisphere at middle-and high-latitude (Manson and Meek, 1986;Teitelbaum et al, 1989;Thayaparan, 1997;Pendleton et al, 2000;Younger et al, 2002;Namboothiri et al, 2004;Taori et al, 2005;Zhao et al, 2005;Beldon et al, 2006). These studies showed that the seasonal behavior of the 8-h tide in the MLT region is different at different latitudes.…”

“…These studies showed that the seasonal behavior of the 8-h tide in the MLT region is different at different latitudes. For example, maximum amplitudes of the 8-h tide in the Northern Hemisphere were observed in the autumn (September-October) at the highlatitude station Esrange (68 • N) (Younger et al, 2002), in autumn and early winter (September-November) at Castle Eaton, UK (52.6 • N, 2.2 • W) (Beldon et al, 2006), in winter and early spring (January-March) at Garchy (47 • N), Montpazier (44 • N) and London, Canada (43 • N) (Teitelbaum et al, 1989;Thayaparan, 1997), and in winter (DecemberFebruary) at Wakkanai (45.4 • N) (Namboothiri et al, 2004). Overall, the 8-h tides at mid-latitude stations in the Northern Hemisphere have similar seasonal features, with maximum amplitudes in the winter months.…”