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



[1] Two meteor radars with enhanced power and sensitivity and located at closely conjugate latitudes (54.6°N and 53.8°S) are employed for interhemispheric comparisons of mean winds and planetary wave structures at periods of ∼8 to 20 days. Our study uses data from June 2008 through May 2010 during which both radars provided nearly continuous wind measurements from ∼80 to 100 km. Monthly mean winds at 53.8°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 ∼5–10 ms−1 at 54.6°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 ∼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 ∼8–10 and 16–20 days and are more confined to late fall and winter at 54.6°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°N (53.8°S) during peak planetary wave responses.