Nitric Oxide Concentration: A New Data Set Derived From SABER Measurements

Vertical profiles of nitric oxide (NO) concentration are derived between 120 and 250 km using updated NO emission rates measured by Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite. The Naval Research Laboratory Mass Spectrometer Incoherent Scatter Radar (MSIS) 2.1 model is used to provide the required parameters of temperature, atomic oxygen number density, and molecule oxygen number density needed to derive the NO concentrations using a non‐local thermodynamic equilibrium (non‐LTE) model. The SABER NO concentration shows a significant correlation with solar activity with larger peak NO concentrations and higher altitude extent during solar maximum years compared to those during the solar minimum years. The SABER NO agrees well with the MSIS 2.1 NO at altitudes above 120 km for all latitudes, while the pronounced SABER‐MSIS NO discrepancy below 120 km is likely due to the temperature underestimation by MSIS 2.1. A detailed error analysis is presented and considers systematic and random errors in all the terms in the non‐LTE model used to derive the NO concentration. Random error in MSIS 2.1 temperature and atomic oxygen dominates the uncertainty in single NO profiles above 120 km. We estimated a systematic error up to ∼36% between 120 and 250 km during solar maximum years. Plain Language Summary Nitric oxide (NO) is a minor constituent of the Earth's thermosphere and regulates the energy budget by emitting infrared radiation that cools the region. Understanding the distribution of the NO concentration is important in understanding the energy redistribution in the Earth's upper atmosphere. In this paper, a new NO concentration data set between 120 and 250 km from January 2002 to the present day is derived from the latest Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) NO emission measurements and Mass Spectrometer Incoherent Scatter Radar (MSIS) 2.1 empirical model of temperature and O, and O2 number density. The derived SABER NO concentration varies with solar activity. The SABER NO agrees well with the empirical MSIS 2.1 NO between 120 and 250 km. Below 120 km, the temperature may be warmer than predicted by MSIS 2.1, leading to a substantial difference between SABER NO and MSIS 2.1 NO. A comprehensive error analysis considering systematic and random errors in all the terms in the model used to derive the NO concentrati