The mean zonal circulation in the meteor zone above Garchy (France) and Kiruna (Sweden)

The large set of data obtained from 6 years of observations by the Garchy meteor radar yields a picture of the mean zonal circulation in the 75–105 km range at 47°N. The annual wind pattern shows that the lower meteor heights (80–90 km) are characterized by strong vertical and seasonal changes and mark a region of transition between the mesospheric monsoonal circulation observed up to around 85 km and another type of circulation above 90 km characterized by a strong steady eastward circulation in the summer and a weak circulation during the rest of the year. These features were also observed over Kiruna (68°N) by another CNET meteor radar situated at this place for 1 yr. The annual wind component prevails in the meteor range and is nearly out of phase below and above the 85–90 km level. Comparisons made with the results from other stations show that these characteristics are probably planetary in character.