Seasonal variation of airglow intensity for the OH(6-2) band (nocturnal means) at El Leoncito (32°S, 69°W). The "burst" on December 15/16, 2000 is the highest day-to-day variation in OH intensity that we have on record (i.e., among more than 1200 nights). This is completely unexpected, for this time of the year, but, similar to the 25APR99 event in O2, it is also accompanied by very strong gravity wave signatures (compare Scheer and Reisin, JASTP 64, 1175-1181, 2002).
next figure (OH temperature)             1997-2001             same for 2002-2003             2006             2007             2008             2009             2010             2011             2012             2013             2014             2015             2016             2017             2018             2019             2020             2022             2023             2024             2025