Nocturnal variation of OH(6-2) and O2(0-1) rotational temperature and band intensity at El Leoncito (32°S, 69°W), during the night 11/12 Oct 2000. The strong variations are essentially due to the semidiurnal tide. Note that for both emissions, the phase of the temperature oscillation precedes the intensity variation. This is consistent with the upward-propagating tidal wave.
Additionally, at 2:30 LST, the OH emission shows a rather mysterious sudden temperature increase of about 20 K in 15 minutes, with the OH intensity increasing only gradually. A much more dramatic intensity rise was observed on August 22, 2001