The importance of mesopause region airglow "bright nights"

J. SCHEER; E.R. REISIN

Praga

Congreso; 26th IUGG General Assembly 2015; 2015

International Union of Geodesy and Geophysics

"Bright nights", when airglow brightness is much greater than usual, are keys to understanding atmospheric dynamics at the emission altitudes. In the mesopause region, the most important airglow emissions of OH and O2 correspond to nominal altitudes of 87 and 95 km, respectively. Since overlap between the emission layers is not great, differences or similarities in the behaviour of the two emissions are of additional diagnostic value.The data base of brightness and rotational temperatures corresponding to these airglow emissions acquired with the Argentine Airglow Spectrometer at El Leoncito (31.80°S, 69.29°W) has grown in size and yearly coverage to be now more suitable for a statistical analysis of this relatively rare phenomenon. We limit scope to the years 2006 to 2014, with about 2940 nights of data and 94 nearly completely documented months, so that cases that we have previously reported are not included, and earlier results can be tested independently.We present new results on the seasonal and year-to-year distribution of bright nights, and case studies of the most prominent cases, with the aim to shed light on the different mechanisms that may be involved.