Quasi‐biennial modulation of the semidiurnal tide in the upper mesosphere above Halley, Antarctica

Abstract

[1] We present an analysis of a long-term archive of horizontal wind data derived from meteor wind observations from a SuperDARN radar at Halley, Antarctica (76°S, 27°W). Systematic differences between the 12-hour component in the meridional wind and the climatological mean are observed showing evidence of a quasi-biennial modulation of the high-latitude semidiurnal tide in the upper mesosphere. The amplitude of the observed tides is enhanced when the equatorial stratospheric quasibiennial oscillation above 10 hPa is westerly. This enhancement is greatest in the summertime tidal amplitudes when the zonal wavenumber one (S = 1) nonmigrating component dominates the semidiurnal wind field, and is coincident with an enhancement of the summertime planetary wave activity in the upper mesosphere. These observations strongly support the hypothesis that the S = 1 component of the semidiurnal tide observed at high latitudes is due to a non-linear interaction between the migrating S = 2 semidiurnal tide and quasi-stationary S = 1 planetary waves.Citation: Hibbins, R. E., P. J. Espy, and M. J. Jarvis (2007), Quasi-biennial modulation of the semidiurnal tide in the upper mesosphere above Halley, Antarctica, Geophys. Res. Lett., 34, L21804,

Asymmetry in the interhemispheric planetary wave-tide link between the two hemispheres

“…In addition to the effect of the SPW in the winter NH, the Antarctic tides might also be affected by the quasi-biennial oscillation (QBO) (Jarvis, 1996;Hibbins et al, 2007). The 2-year modulation is visible in the interannual variability of the Rothera SDT amplitude (Fig.…”

Winds and tides in the mid-latitude Southern Hemisphere upper mesosphere recorded with the Falkland Islands SuperDARN radar

“…Although the data represent only one year, and previous studies have revealed significant natural interannual variability in the MLT region (e.g. Fraser et al, 1989;Portnyagin et al, 2006;Baumgaertner et al, 2006;Hibbins et al, 2007a;Sandford et al, 2010) we aim to highlight and interpret some of the observed similarities and differences. Fritts et al (2010) used a meteor radar located at Rio Grande on Tierra del Fuego (54 • S, 68 • W) to study the large scale winds and tides at meteor ablation altitudes during the period May 2008 to September 2009.…”

“…The period around early April 2010 is the only period of downtime longer than 3 days and there is no tendency for the radar to fail around a particular time of day and hence no diurnal bias in the data coverage. Two-component horizontal winds around 90 km altitude were calculated from radar echoes from meteor ablation trails using the technique described in Hibbins et al (2007a). Briefly, a singular value decomposition fit to the individual meteor drift velocities recorded in the first four range gates of the radar between 180 and 405 km was performed for each hour of operation provided meteors were recorded in at least 5 different beams during the hour (Hall et al, 1997;Bristow et al, 1999;Hussey et al, 2000;Yukimatu and Tsutsumi, 2002).…”

Relationship between variability of the semidiurnal tide in the Northern Hemisphere mesosphere and quasi-stationary planetary waves throughout the global middle atmosphere

“…In addition, note that some differences are shown in the correlation plots between the two years, which might be due to the effect of the quasibiennial oscillation (QBO) that has opposite phases in the two years (e.g. Espy et al,1997;Jacobi et al, 1998;Hibbins et al, 2007). The relation between interannual variations in the SPW and tides has been presented in the most recent study ).…”