Seasonal variation of O₂(0-1) rotational temperature (nocturnal means) at El Leoncito (32°S, 69°W). The very low temperature on January 8, 2001 is correlated with a similar behaviour in OH temperature and O2 intensity.
next figure (O2 intensity)             1997-2001             same (O2 temperature) for 2002             2006             2007             2008             2009             2010             2011             2012             2013             2014             2015             2016             2017             2018             2019             2020             2022             2023             2024             2025