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, NM. Sixty four hours of observations were conducted on 8 nights in 1994-95. The mean vertical wind and temperature vari-ances were 4.32 m2/s2 and 80.3 K2. When averaged between about 92.5±6 km, the mean vertical heat flux was -1.80±0.17 Km/s and the mean cooling rate was -35.0±2.2 K/day. 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 assuming values near 300 m2/s for the vertical diffusivity. Published rocket measurements of the turbulent heating caused by breaking gravity waves are only a few K/day in this height range. Thus, the net effect of dissipating gravity waves is a significant cooling of the mesopause region.
Figure 1 a) Mean vertical wave number and b) temporal frequency spectra of the vertical wind perturbations measured during the 8 observation periods at Starfire. c) Mean vertical wave number and d) temporal frequency spectra of the temperature perturbations. The spectra were computed from 64 h of observations between 85 and 100 km. The photon noise floors have been subtracted from the lower spectra.
Figure 2 a) Vertical heat flux and b) dynamical cooling rate profiles measured during the 8 observation periods at Starfire. The thick curves are the 7 night means which exclude the 3 Feb profiles. The profiles were smoothed vertically using a 4 km FWHM Hamming window.
Figure 3 a) Mean vertical heat flux and b) dynamical cooling rate profiles. The mean profiles were smoothed vertically using a 4 km FWHM Hamming window and exclude the 3 Feb data.
