A data assimilation technique for determining tidal and zonal mean structure in the mesosphere and lower thermosphere from satellite measurements of wind and temperature

This poster presents a method for determining the structure of the migrating diurnal and semi-diurnal tides, the zonal mean state, and the damping of the tides due to gravity wave drag and diffusion within the mesosphere and lower thermosphere. This novel approach forgoes the usual local time spectral analysis of each field variable. Instead, the horizontal wind and temperature fields are used simultaneously to obtain an estimate of tidal and mean state components of these fields on a daily basis. This is accomplished by means of a data assimilation technique that incorporates a tide and mean state model. A new tidal model based on the method of multiple scales was developed for this purpose. The details of this model and the assimilation technique are described. This techniques has been applied to the daily measurements of winds and temperatures by the High Resolution Doppler Imager on UARS and some results concerning the structure of the mean winds and temperatures and the structure and variability of the tides will be shown.