Articles | Volume 33, issue 11
Ann. Geophys., 33, 1349–1359, 2015
Ann. Geophys., 33, 1349–1359, 2015

Regular paper 06 Nov 2015

Regular paper | 06 Nov 2015

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

H. Iimura1, D. C. Fritts1, D. Janches2, W. Singer3, and N. J. Mitchell4 H. Iimura et al.
  • 1GATS Inc., Boulder, Colorado, USA
  • 2Space Weather Lab., GSFC/NASA, Goddard, Maryland, USA
  • 3Leibniz-Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Germany
  • 4Department of Electronic and Electrical Engineering, The University of Bath, Bath, UK

Abstract. A study of the quasi-5-day wave (5DW) was performed using meteor radars at conjugate latitudes in the Northern and Southern hemispheres. These radars are located at Esrange, Sweden (68° N) and Juliusruh, Germany (55° N) in the Northern Hemisphere, and at Tierra del Fuego, Argentina (54° S) and Rothera Station, Antarctica (68° S) in the Southern Hemisphere. The analysis was performed using data collected during simultaneous measurements by the four radars from June 2010 to December 2012 at altitudes from 84 to 96 km. The 5DW was found to exhibit significant short-term, seasonal, and interannual variability at all sites. Typical events had planetary wave periods that ranged between 4 and 7 days, durations of only a few cycles, and infrequent strongly peaked variances and covariances. Winds exhibited rotary structures that varied strongly among sites and between events, and maximum amplitudes up to ~ 20 m s−1. Mean horizontal velocity covariances tended to be largely negative at all sites throughout the interval studied.

Short summary
The quasi-5-day wave at mid- and high-latitudes in the mesosphere and lower-thermosphere was compared between the hemispheres using meteor radar horizontal wind measurements, spanning June 2010 to December 2012. Variances of the quasi-5-day wave showed a wave activity from July to August in both hemispheres and in April 2012 in the Northern Hemisphere and November 2012 in the Southern Hemisphere with unique characteristics at each site.