A decade‐long climatology of terdiurnal tides using TIMED/SABER observations

Abstract

In this paper, we globally characterize the solar terdiurnal tide in the 80–110 km region of Earth's atmosphere through analysis of 10 years of temperature measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry instrument on the Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics spacecraft. The Sun‐synchronous (“migrating”) component (TW3), which is longitude‐independent and achieves maximum amplitudes of order of 5 K (10 K) at 90 km (110 km), not too different than the 7–15 K amplitudes that are typical of the migrating diurnal and semidiurnal tides in this region. Significant longitude variability (∼ 20–25%) in terdiurnal temperature amplitudes also exists, which is decomposed into zonal wave number components. The largest of these (TE1, TW4, and TW5) reveal distinct seasonal‐latitudinal and height versus latitude patterns and interannual consistency. In addition, it is demonstrated that these particular components vary in ways that suggest that they originate from nonlinear interactions between diurnal and semidiurnal tides, specifically between DE3 and SW2 for TE1, between DW2 and SW2 for TW4, and between DW1 and SW4 for TW5. We also demonstrate that the terdiurnal tides derived here are not influenced to any significant degree by aliasing due to the presence of other waves.