Evidence for a solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere

Martin G. Mlynczak, F. Javier Martin-Torres, B. Thomas Marshall, R. Earl Thompson, Joshua Williams, Timothy Turpin, David P. Kratz, James M. Russell, Tom Woods, Larry L. Gordley

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Abstract

We present direct observational evidence for solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere. By analyzing nearly five years of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, we show that the annual mean infrared power radiated by the nitric oxide (NO) molecule at 5.3 μm has decreased by a factor of 2.9. This decrease is correlated (r = 0.96) with the decrease in the annual mean F10.7 solar index. Despite the sharp decrease in radiated power (which is equivalent to a decrease in the vertical integrated radiative cooling rate), the variability of the power as given in the standard deviation of the annual means remains approximately constant. A simple relationship is shown to exist between the infrared power radiated by NO and the F10.7 index, thus providing a fundamental relationship between solar activity and the thermospheric cooling rate for use in thermospheric models. The change in NO radiated power is also consistent with changes in absorbed ultraviolet radiation over the same time period. Computations of radiated power using an empirical model show much less variability than observed by SABER.

Original languageEnglish
Pages (from-to)A12302
JournalJournal of Geophysical Research: Space Physics
Volume112
Issue number12
DOIs
Publication statusPublished - Dec 1 2007
Externally publishedYes

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ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Mlynczak, M. G., Martin-Torres, F. J., Marshall, B. T., Thompson, R. E., Williams, J., Turpin, T., Kratz, D. P., Russell, J. M., Woods, T., & Gordley, L. L. (2007). Evidence for a solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere. Journal of Geophysical Research: Space Physics, 112(12), A12302. https://doi.org/10.1029/2006JA012194