- Top of page
- 1. Introduction
- 2. Data and Analysis
- 3. Results
- 4. Discussion and Conclusions
 The large influence of nonmigrating tides on nitric oxide variability in the lower thermosphere is revealed for the first time using data from the TIMED (tides) and SNOE (nitric oxide) satellites. Between March and October, a wave-4 like longitude variation in nitric oxide density residuals is observed with peak-to-peak values of 40% between 30°S–30°N and 100–135 km. This variation becomes wave-3 like in December and January with wave-4/wave-3 transitions in November and February. It is quantitatively shown that the nitric oxide longitude variations are caused by nonmigrating tides in neutral gas density. The DE3 (diurnal eastward wavenumber 3) tidal component causes the observed wave-4 variation. The combination of DE2 (diurnal eastward wavenumber 2) and SE1 (semidiurnal eastward wavenumber 1) causes the observed wave-3 variation. These results suggest that similar effects will be found in other constituents and airglow emissions important to the aeronomy of the mesosphere and lower thermosphere.