Auroral E-region neutral wind by EISCAT radar

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Based on the data base obtained by the European Incoherent Scatter (EISCAT) radar located in the northern Scandinavia, we have studied E-region neutral wind characteristics between 95 km and 119 km obtained under geomagnetic quiet conditions over a solar cycle between November 1986 and October 1996. Data of 56 days are analyzed and grouped according to season or solar activity to investigate variations of the wind in different seasons and solar cycle conditions. Seasonal and solar cycle dependences of mean winds as well as diurnal and semidiurnal amplitudes are found, while the corresponding phases appear to be less sensitive to seasonal and solar cycle variations. No prominent seasonal nor solar cycle dependence are found for the vertical component.The zonal mean wind blows mainly eastward below 116km for all seasons, and it is the strongest (about 45ms^<-1>) in summer and the weakest (about 25ms^<-1>) in winter. The eastward mean wind amplitude below 110km are enhanced by about 15ms^<-1> during high solar activity period. The zonal mean wind turns from eastward to westward at upper E-region heights, and the turning height varies with season and solar activity. The meridional mean wind tends to shift from southward in winter to northward in summer and also from low to high solar activity periods, and its amplitude is generally less than 20ms^<-1> in this part of the E-region.Furthermore, seasonal variations for different solar activity are also investigated. It is found that the mean wind in equinox is most sensitive to solar activity in all seasons.