Search for solar connections in neutral winds at 80-100 km by MF/Meteor radars in April 2002

During the CEDAR-TIMED storm campaign in April 2002, Medium Frequency and Meteor Wind radars at more than 20 worldwide locations provided continuous wind measurements in the altitude range of 80-100 km. Preliminary results show that the zonal mean winds and amplitudes of the diurnal tide at low latitudes, such as at Kauai (22N) and Rarotonga (22S), are much larger during the first half of the month compared to the second half of the month. This phenomenon may be related to variations in the solar flux. Winds at high latitudes such as at Andenes (67N) show a significant change in the pattern presented in geomagnetic coordinates during the storm on April 17th, which may be related to the change in geomagnetic activity. Wind structures in the mesopause region are extremely complex. Large variations were observed at various radar locations, which may be caused by planetary waves and tides, that may mask the effects of geomagnetic storms.