11:00 AM - 1:00 PM
[PEM12-P14] Observational evaluation of temperature/wind perturbations associated with small-scale AGWs : Momentum flux estimation
Keywords:Gravity waves, Lidar, Airglow imaging
In this study, we tried to identify small-scale (less than 100 km) and short-period (less than 1 h) gravity waves by using the Tromsoe Na lidar. Gravity waves contribute significantly to the wind field and thermal balance in the mesosphere and lower thermosphere (MLT) region because they vertically transport horizontal momentum from the lower atmosphere. It is also pointed out that, in particular, smaller-scale and shorter-period waves tend to transport larger momentum. Small-scale gravity waves in the MLT region are mainly studied with airglow imaging measurements. The airglow measurements, however, cannot observe temperature and wind perturbations directly, which are necessary for the estimation of the wave’s momentum flux. Based on temperature and wind perturbations with the five-direction lidar, we evaluate the dynamical effect of small-scale gravity waves propagating in the upper atmosphere quantitatively.
On the simultaneous measurement of the lidar and airglow imaging on 20 January 2018, we identified the gravity wave with a horizontal wavelength of 37 km, a phase speed of 85 m s-1, and a wave period of 7.2 min. In this presentation, we will discuss its momentum flux estimation by comparing the wave parameters calculated by both measurements.