Publication Date:
2014-03-26
Description:
Infrared radiative cooling of the thermosphere by carbon dioxide (CO 2 , 15 µm) and by nitric oxide (NO, 5.3 µm) has been observed for 12 years by the SABER instrument on the TIMED satellite. For the first time we present a record of the two most important thermospheric infrared cooling agents over a complete solar cycle. SABER has documented dramatic variability in the radiative cooling on timescales ranging from days to the 11-year solar cycle. Deep minima in global mean vertical profiles of radiative cooling are observed in 2008–2009. Current solar maximum conditions, evidenced in the rates of radiative cooling, are substantially weaker than prior maximum conditions in 2002–2003. The observed changes in thermospheric cooling correlate well with changes in solar ultraviolet irradiance and geomagnetic activity during the prior maximum conditions. NO and CO 2 combine to emit 7 x 10 18 more Joules annually at solar maximum than at solar minimum.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
Permalink