Large mesospheric inversion layer due to breaking of small-scale gravity waves: Evidence from Rayleigh lidar observations over Gadanki (13.5°N, 79.2°E)

摘要: Abstract On the night of 24th January 2007, Rayleigh lidar temperature observations over Gadanki (13.5°N, 79.2°E) show an occurrence a strong mesospheric inversion layer (MIL), which is selected for case study to investigate role gravity wave breaking in causing inversion. The MIL event occurs altitude region ∼79–84 km with amplitude ∼50 K and thickness 4.5 km. two dimensional spectral analysis on perturbations shows presence dominant vertical wavelength 6.4 km period 38 min height ∼30.0–55.0 km shorter 33 min above 55.0 km. other characteristics have been obtained from dispersion relation using rocketsonde winds SHAR (13.7°N, 80.2°E) medium frequency (MF) radar Tirunelveli (8.7°N, 77.8°E) regions 25–65 km 80–90 km respectively. horizontal phase speed are found be ∼50 m/s ∼110 km 30.0–55.0 km ∼57 m/s ∼129 km 55.0 km respectively indicating internal wave, rather than inertia-gravity wave. In this study, condition saturation checked ratio it that, 80 km, gets saturated dissipation, subsequently can lead turbulence, cooling heating. eddy diffusion coefficient increases ∼54 m2/s ∼284 m2/s height, decreases. theoretically computed heating rate due turbulence generated by compares well observations.