The diurnal tide as observed in TIMED/SABER temperatures

Four years of temperature measurements by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite are analyzed to examine the seasonal and interannual variations of the durnal tide in the mesosphere. Previous satellite studies have obtained long-term, global-scale depictions of diurnal tides in the middle atmosphere. However, the nature of satellite sampling is that the dynamic features are shifted Doppler-shifted by the satellite motion. As a result, the migrating tide structure is aliased into the zonal mean field for sun-synchronous satellites. Precessing satellites allow a composite picture of the dynamic field to be collected in local time that can be analyzed for diurnal or semidiurnal signals. However, these composites typically take 1-2 months to collect with two node (i.e., the ascending/descending portions of the satellite orbit) sampling. In this paper, we use a new method to extract the migrating tides from observations taken by a slowly precessing satellite. Specifically, we present daily estimates of both the migrating and nonmigrating components of the diurnal tide from the lower stratosphere to the lower thermosphere as observed by SABER/TIMED. We examine evidence of nonlinear interaction between the tides and other wave modes and we discuss the impacts that the tides may have on the zonal mean structure in the mesosphere and lower thermosphere as well as the upper atmosphere and ionosphere.