Diurnal nonmigrating tides from TIMED Doppler Interferometer wind data: Monthly climatologies and seasonal variations

[ 1] TIMED Doppler Interferometer (TIDI) measurements of zonal and meridional winds in the mesosphere/lower thermosphere are analyzed for diurnal nonmigrating tides ( June 2002 to June 2005). Climatologies of monthly mean amplitudes and phases for seven tidal components are presented at altitudes between 85 and 105 km and latitudes between 45 degrees S and 45 degrees N ( westward propagating wave numbers 2, 3, and 4; the standing diurnal tide; and eastward propagating wave numbers 1, 2, and 3). The observed seasonal variations agree well with 1991 - 1994 UARS results at 95 km. Comparisons between the TIDI results and global scale wave model (GSWM) and thermosphere-ionospheremesosphereelectrodynamics general circulation model (TIME-GCM) tidal predictions indicate that the large eastward propagating wave number 3 amplitude is driven by tropical tropospheric latent heat release alone. In contrast, latent heating and planetary wave/migrating tidal interactions are equally important to westward 2 and standing diurnal tidal forcing. There is good quantitative agreement between TIDI and the model predictions during equinox, but the latter tend to underestimate the westward 2 and standing diurnal tide during solstice. Neither model reproduces the observed seasonal variations of the eastward propagating components.