Unusual characteristics of lower thermosphere prevailing winds at South Pole



Meteor radar measurements of meridional winds near 95 km altitude, along four orthogonal azimuth directions approximately 2° from the geographic South Pole, were made between January 19, 1995, and January 26, 1996. Herein we report analyses of the prevailing (daily mean) wind component covering the period from January 19 through June 20, 1995. The observed phenomena include (a) A regular month-to-month migration in the phase of the s=1 quasi-stationary component of the wind field; (b) During April, a 10-day period of strong net wind divergence from the pole; (c) evidence for upwelling associated with very high magnetic activity. It is speculated that the wind divergence event may be associated with the mesospheric penetration of momentum fluxes known to accompany intense wave 1 activity in the Southern Hemisphere during April [Miles et al., 1994].