Variabilities of Low‐Latitude Migrating and Nonmigrating Tides in GPS‐TEC and TIMED‐SABER Temperature During the Sudden Stratospheric Warming Event of 2013

The Global Positioning System deduced total electron content (TEC) data at 15°N (geomagnetic), which is the crest region of equatorial ionization anomaly, are used to study tidal variabilities during the 2013 sudden stratospheric warming (SSW) event. The results from space‐time spectral analysis reveal that the amplitudes of migrating diurnal (DW1) and semidiurnal (SW2) tides are larger than those of nonmigrating tides. After the SSW onset, the amplitudes of DW1, SW2, SW1, and DS0 increase. Moreover, they show 16 day variations similar to the periodicity of the high‐latitude stratospheric planetary wave (PW), suggesting that the nonmigrating tides (SW1 and DS0) are possibly generated due to nonlinear interaction of migrating tides with PW. Similar spectral analysis on temperature at 10°N obtained from the Sounding of Atmosphere by Broadband Emission Radiometry (SABER) shows that the SW2 enhances at stratospheric heights and the SW2 is more dominant at 80–90 km, but its amplitude decreases around 100 km. The amplitudes of nonmigrating tides become comparable to those of SW2 around 100 km, and their contribution becomes increasingly important at higher heights. This suggests that the nonlinear interaction between migrating tides and PW occurs at low‐latitude upper mesospheric heights, as SW2 exhibits 16 day periodicity in SABER temperature at 100 km as observed in TEC. Besides, it is observed that the eastward propagating tides are less dominant than westward propagating tides in both TEC and SABER temperatures. Key Points Migrating tides in 15°N (geomagnetic) GPS‐TEC and 10°N SABER temperatures show 16 day variability indicating nonlinear PW tidal interactions Migrating semidiurnal tide (SW2) enhances largely during the SSW and dominates nonmigrating tides in stratosphere and lower mesosphere. Nonmigrating tides enhance at 100 km, revealing that the interaction occurs at low‐latitude upper mesospheric heights Plain Language Summary Though there is an enhancement of semidiurnal tide during the sudden stratospheric warming events, it is not known whether the enhancement is due to migrating tide or nonmigrating tide. If it is due to nonmigrating tides, how and where are they generated? The results from this paper show that though migrating semidiurnal tide is so dominant at stratosphere and lower mesospheric heights, its amplitude decreases at heights around 100 km, where nonmigrating tidal amplitudes become significant. This suggests that the nonlinear intera