Observations of gravity wave propagation in the all-sky infrared airglow

The preliminary results of the nightglow wave structure with an infrared all-sky camera at Maimaga optical station (phi = 63 degrees N, lambda =129.5 degrees E, Phi = 56 degrees; Lambda = 199.7 degrees) within the framework of the international program PSMOS (Planetary Scale Mesopause Observing System) are presented. An analysis of the data obtained in March 1999 shows that small-scale waves predominantly propagate to the west. The wavelengths registered varied from 15 to 35 km (the average value equals similar to 25 km). The observed horizontal phase velocities ranged from 14 to 59 m/s (the average value equals similar to 36 m/s). The estimated periods are within the limits of 7-19 min (the average value equals similar to 12 min). It has been shown that the activity of short-waves (with a wavelength shorter than 17.5 km) is low as compared to observations at lower latitudes. Moreover, in contrast to the isotropic propagation distribution at lower latitudes, the waves in this range propagated northwestward during the period under consideration.