Altitude and temperature of the mesopause at 69 N latitude in winter

Temperature profiles of the altitude region 80-110 km are derived from the measurement of the Doppler width of the laser-excited D2 resonance line of free sodium atoms. For the altitude range 85-95 km the altitude resolution, integration time, and error bar of individual temperature points are typically 1 km, 10 min, and ±5 K, respectively. Temperature data obtained during the two winter seasons 1985/1986 and 1986/1987 near Andenes, Norway (69oN, 16oE), are presented. For December-March, 743 temperature profiles are combined into four monthly mean profiles. For each of the 4 months the altitude of the mesopause is found to be 100 ± 2 km. The mesopause temperature is close to 193 K from December through February but drops to 170 K in March.