OBSERVATION OF A QUASI 16-DAY OSCILLATION IN THE POLAR SUMMER MESOSPHERIC TEMPERATURE

Night-time measurements of the hydroxyl Meinel (3,1) rotational band w ere used to infer the mesospheric temperature over Scandinavia from Ju ne through August, 1992. The resulting temperature time series showed spectrally-distinct, statistically-significant fluctuations with perio ds between 2 and 16 days, although only the 16-day oscillation will be discussed here. The period, amplitude and temporal history of this wa ve agree with model predictions and radar wind measurements of the (1, 3) Rossby normal mode, and are therefore consistent with its identific ation as the temperature signature of this mode. The relationship of t hese summer temperature oscillations and the occurrence of noctilucent clouds is discussed.