Climatology of middle- and low-latitude daytime F region disturbance neutral winds measured by Wind Imaging Interferometer (WINDII)

We have modeled the global climatology of middle- and low-latitude F region daytime disturbance neutral winds using extensive measurements by the Wind Imaging Interferometer (WINDII) instrument on board the UARS. The perturba tion winds were obtained by subtracting the quiet time values from the dist urbed winds along the satellite orbit, which effectively removes average me asurement bias. The zonal disturbance winds are mostly westward (except in the early morning sector), increase with latitude, and have largest values in the late afternoon sector. In general, the meridional perturbation winds are equatorward, increase linearly with latitude, and decrease from early morning to afternoon hours. The zonal and meridional perturbations increase roughly linearly with Kp and expand to lower latitudes with increasing mag netic activity. The meridional disturbance winds are largest for low solar flux conditions. We present empirical analytical models for longitudinally averaged disturbance winds from 60 degrees to the equator. Our model winds are in poor agreement with results from the empirical wind model Horizontal Wind Model-93 during the entire daytime period. There are also important d iscrepancies between the average perturbations winds from WINDII and the Na tional Center for Atmospheric Research thermosphere-ionosphere electrodynam ic general circulation model, particularly at midlatitudes. These differenc es could be explained in part by the storm time dependence of the disturban ce winds and by the variability of the high-latitude electric fields.