COMPARISON OF ALOHA-93, ANLC-93 AND ALOHA-90 OBSERVATIONS OF THE HYDROXYL ROTATIONAL TEMPERATURE AND GRAVITY-WAVE ACTIVITY

Hydroxyl airglow measurements during the ALOHA-93, ALOHA-90 and ANLC-9 3 campaigns are used to evaluate features of the temperature variation of the mesopause region. Each campaign shows a persistent pattern in the averaged local time variation of temperature with peak-to-peak amp litudes of 5 K to 15 K, suggestive of the presence of tidal modulation . The nightly temperature variance, after detrending to remove low fre quency variations due to tides, is shown to be significantly less duri ng the Hawaiian campaigns than during the ANLC-93 and other campaigns at sites where significant orographic excitation of waves might be exp ected.