Empirical model of 90–120 km horizontal winds from wind‐imaging interferometer green line measurements in 1992–1993

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Abstract
An empirical model of horizontal winds is developed based on wind‐imaging interferometer (WINDII) green line observations between 90 and 120 km in 1992–1993. The model includes mean winds, solar diurnal and semidiurnal tides, and some planetary wave components, as well as annual and semiannual variations in these fields. Its formulation is similar to that of HWM‐90 and HWM‐93 of Hedin et al. [1991, 1996], but greatly modified and extended to use the higher resolution global wind measurements now available from WINDII. While the technique will only reach fruition when results can be combined from the wind measurements of several years by the different instruments on the UARS satellite, this interim, but updated model provides improved representation of the temporal and geographic variations of the wind fields compared to the current reference models. The model generated climatological mean wind, diurnal tides, and some samples of the entire wind motion fields are presented and compared with the WINDII measurements and analysis results obtained from the data sets by different methods to check the consistencies between the model representations and the observations. This study also reveals a dual cell structure in the meridional component of the diurnal tides with two amplitude maxima centered around 95 and 102 km near 20° latitude and strongly symmetric about the equator at equinox. Large interannual variabilities are found to exist in both diurnal wind components with maximum amplitudes of ∼ 40 and 55 m/s for the zonal and meridional, respectively, at the vernal equinox of 1992.