  An accurate estimate of the energy budget (heating and cooling) of the
ionosphere and thermosphere, especially during space weather events, has been a
challenge. The abundance of Nitric Oxide (NO), a minor species in the
thermosphere, is an important component of energy balance here because its
production comes from energy sources able to break the strong bond of molecular
nitrogen, and infrared emissions from NO play an important role in
thermospheric cooling. Recent studies have significantly improved our
understanding of NO chemistry and its relationship to energy deposition in the
thermospheric photochemical reactions. In this study, the chemical scheme in
the Global Ionosphere Thermosphere Model (GITM) is updated to better predict
the lower thermospheric NO responses to solar and geomagnetic activity. We
investigate the sensitivity of the 5.3-micron NO emission to F10.7 and Ap
indices by comparing the global integrated emission from GITM with an empirical
proxy derived from the Sounding of the Atmosphere using Broadband Emission
Radiometry measurements. GITM's total emission agrees well within 20% of the
empirical values. The updated chemistry scheme significantly elevates the level
of integrated emission compared to the previous scheme. The inclusion of
N2(A)-related production of NO contributes an additional 5-25% to the emission.
Localized enhancement of ~70% in column density and a factor of three in column
emission are simulated at a moderate geomagnetic level.
