Vertical temperature and density patterns in the Arctic mesosphere analyzed as gravity waves

Abstract

Three series of rocket soundings were conducted from high latitude sites during winter. In the first series, four pitot pressure soundings were launched during a 13-hour period from Ft. Churchill, Canada (59° N) on January 31, and February 1, 1967. The second series consisted of one pitot sounding and two grenade soundings carried out during a 3-hour period on January 13–14, 1970. Temperature and wind profiles and one density profile were observed independently to obtain the thermodynamic structure, the wind structure, and thus their interdependence in the mesosphere. The third series of soundings was conducted from Point Barrow, Alaska (71° N) on December 6, 1971. This series consisted of five soundings of which the first two and the last two were pitot-grenade pairs. Temperature profiles from all soundings in each series were averaged, and a smooth curve (or series of smooth curves) drawn through the points. A hydrostatic atmosphere based on the average, measured temperature profile was computed, and deviations from the mean atmosphere were analyzed in terms of gravity wave theory. The vertical wavelengths of the deviations were 10–20 km, and the wave amplitudes slowly increased with height. The experimental data were matched by calculated gravity waves having a period ranging between 15 and 80 minutes and horizontal wavelengths of 60 to 280 km. Our interpretation is generally consistent with the results of others who have studied gravity-acoustic waves in the atmosphere. The wind measurements are consistent with the thermodynamic measurements. The results also suggest that gravity waves travelled from East to West with a horizontal phase velocity of approximately 60 m/s.