High resolution temperature profiles of the mesopause region above Fort Collins, CO (40.6¿N, 105¿W) were measured with a Na lidar on the nights of March 2--3 and April 15--16, 1990, during the ALOHA-90 campaign. This paper reports the initial scientific analysis of these data which were used to compute (1) the altitude profiles of relative atmospheric temperature perturbations, (2) the mean Brunt-Vaisala frequency in the mesopause region, and (3) the vertical shear variance of horizontal winds. On March 2--3 and April 15--16, the rms temperature perturbations were 5.7% and 7.1%, the average Brunt-Vaisala periods were 4.9 min and 4.6 min, and the wind shear variances were 878 (ms-1/km)2 and 967 (ms-1/km)2, respectively. ¿American Geophysical Union 1991