Measurements of the dynamical cooling rate associated with the vertical transport of heat by dissipating gravity waves in the mesopause region at the Starfire Optical Range, New Mexico

Vertical heat flux and cooling rate profiles of the mesopause region resulting from dynamic processes were computed using wind and temperature measurements made with a Na lidar at the Starfire Optical Range near Albuquerque, New Mexico. Sixty five hours of observations were conducted on eight nights in 1994-1995. The mean vertical. wind and temperature variances were 4.32 m²/s² and 80.3 K². When averaged (over seven nights) between about 92.5 ± 6 km, the mean vertical heat flux was -2.29 ± 0.43 Km/s, the mean cross-correlation coefficient for the wind and temperature fluctuations was -0.12 ± 0.02, and the mean cooling rate was -30.9 ± 5.2 K/d. The mean heat flux and cooling rate profiles reach their maximum negative values just above 90 km where the modeled chemical and measured turbulent heating are maximum. The mean cooling rate is comparable to theoretical predictions (-36 K/d) assuming values near 320 m²/s for the vertical diffusivity. Published rocket measurements of the turbulent heating caused by breaking gravity waves are only a few K/d in this height range. Thus the net effect of dissipating gravity waves is a significant cooling of the mesopause region.