Thermospheric wind data obtained from the Atmosphere Explorer E and Dynamics Explorer 2 satellites have been combined with wind data for the lower and upper thermosphere from ground‐based incoherent scatter radar and Fabry‐Perot optical interferometers to generate a revision (HWM90) of the HWM87 empirical model and extend its applicability to 100 km. Comparison of the various data sets with the aid of the model shows in general remarkable agreement, particularly at mid and low latitudes. The ground‐based data allow modeling of seasonal/diurnal variations, which are most distinct at mid latitudes. While solar activity variations are now included, they are found to be small and not always very clearly delineated by the current data. They are most obvious at the higher latitudes. The model describes the transition from predominately diurnal variations in the upper thermosphere to semidiurnal variations in the lower thermosphere and a transition from summer to winter flow above 140 km to winter to summer flow below. Significant altitude gradients in the wind are found to extend to 300 km at some local times and pose complications for interpretation of Fabry‐Perot observations.

Based on zonally averaged TIDI meridional wind data from one yaw period (2004079 -140) during equinox, we examine the latitudinal and altitudinal distribution of the migrating diurnal and semi-diurnal tides using least squares fitting method to provide a global view of these tidal waves. The TIDI results are compared with Global Scale Wave Model 00 output for the month of April. The diurnal tide amplitude distribution and are in a good agreement. The TIDI results show a lower peak altitude (97 km) while GSWM00 peaks at 102 km. The vertical wavelength from the TIDI is about 20 km while the model predicts 25 km. The semi-diurnal tide comparisons are also reasonable. Both model and TIDI data show peak amplitudes at 45° latitude. The TIDI meridional winds compare very well with ground based meteor radar measurements at Maui. The zonal wind discrepancies are not unexpected.

The TIMED Doppler Interferometer (TIDI) is a Fabry-Perot interferometer designed to measure winds, temperatures, and constituents in the mesosphere and thermosphere (60-300 km) region of the atmosphere as part of the TIMED mission. TIDI is a limb viewer and observes emissions from OI 557.7 nm, OI 630.0 nm, OII 732.0 nm, O 2 (0-0), O 2 (0-1), Na D, OI 844.6 nm, and OH in the spectral region 550-900 nm. Wind measurement accuracies will approach 3 ms -1 in the mesosphere and 15 ms -1 in the thermosphere. The TIDI instrument has several novel features that allow high measurement accuracies in a modest-sized instrument. These include: an optical system that simultaneously feeds the views from four scanning telescopes which are pointed at ±45° and ±135° to the spacecraft velocity vector into a high-resolution interferometer, the first spaceflight application of the circle-to-line imaging optic (CLIO), and a high quantum efficiency, low noise CCD.