Midlatitude mesosphere/lower thermosphere meridional winds and temperatures measured with meteor radar Original Research Article

A meteor radar to measure hourly mean horizontal winds in the 80–100 km height range and daily temperatures near 90 km is operating at Collm (51.3°N, 13°E) since summer 2004. Here we present changes of the meridional wind jet in comparison with temperature fluctuations from August 2004 to May 2006 at time scales of 11–30 days. Whereas in summer no direct correlation between wind and temperature is visible, the meridional circulation at 85 km in winter is positively correlated and nearly in phase with temperatures, so that northward/southward winds are generally accompanied by higher/lower temperatures. This behaviour is in accordance with the dynamical forcing of mesopause region temperatures, which is modulated by planetary waves, gravity wave fluctuations and stratospheric warmings. Numerical modelling of MLT planetary waves show that temperature oscillations at 90 km and winds at 85 km due to those waves have a phase difference of several days, so that planetary waves probably are not the reason for the temperature/wind coupling.