Linda A. Hunt1, Martin G. Mlynczak2, James Russell III3, and B. Thomas Marshall4, and the SABER Science Team 1 Science Systems and Applications, Inc., 2 NASA Langley Research Center 3 Hampton University, 4 GATS, Inc.
We examine the time evolution of infrared radiation from nitric oxide (NO) and carbon dioxide (CO2) in the terrestrial thermosphere (z > 100 km) from 1947 to 2019. These comparisons are afforded by the nearly 18-year (and counting) record of infrared emission measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA TIMED satellite that began in January, 2002. The infrared emission represents the last step in the conversion to heat in the atmosphere of energy that originated as solar ultraviolet radiation, or within the solar wind, or as solar ejecta such as coronal mass ejections. SABER data cover most of solar cycle (SC) 23 and all of SC 24 to date. The new Thermosphere Climate Index (TCI) enables the extension of the SABER record back to 1947, over 70 years, offering an excellent comparison of solar variability over these six solar cycles. Solar cycles 19 through 23 were very similar in the total infrared emission radiated from the thermosphere, despite markedly different cycles in length and sunspot number. SC 24 is turning out to be quite weak by comparison, but with regards to infrared cooling by nitric oxide, has not (yet) reached the low levels of emission during the last solar minimum in 2009. The radiative cooling measurements provide understanding of the processes of deposition and conversion of energy in Earth’s magnetosphere-ionosphere-thermosphere system, a topic which remains a frontier of research in solar-terrestrial physics. Acknowledgement: We gratefully acknowledge ongoing support from the Thermosphere-Ionosphere-Mesosphere-Energetics and Dynamics satellite mission of the NASA Heliophysics Division.
Mode of presentation: oral (Need to be confirmed by the SOC)