A conjugate study of mean winds and planetary waves employing enhanced meteor radars at Rio Grande, Argentina (53.8 degrees S) and Juliusruh, Germany (54.6 degrees N)

Two meteor radars with enhanced power and sensitivity and located at closely conjugate latitudes (54.6 degrees N and 53.8 degrees S) are employed for interhemispheric comparisons of mean winds and planetary wave structures at periods of similar to 8 to 20 days. Our study uses data from June 2008 through May 2010 during which both radars provided nearly continuous wind measurements from similar to 80 to 100 km. Monthly mean winds at 53.8 degrees S exhibit a stronger westward zonal jet in spring and early summer at lower altitudes and no westward winds at higher altitudes. In contrast, westward mean winds of similar to 5-10 ms(-1) at 54.6 degrees N extend to above 96 km during late winter and early spring each year. Equatorward mean winds extend approximately from spring to fall equinox at both latitudes with amplitudes of similar to 5-10 ms(-1). Meridional mean winds are more variable at both latitudes during fall and winter, with both poleward and equatorward monthly means indicating longer-period variability. Planetary waves seen in the 2 day mean data are episodic and variable at both sites, exhibit dominant periodicities of similar to 8-10 and 16-20 days and are more confined to late fall and winter at 54.6 degrees N. At both latitudes, planetary waves in the two period bands coincide closely in time and exhibit similar horizontal velocity covariances that are positive (negative) at 54.6 degrees N (53.8 degrees S) during peak planetary wave responses.