Storm-Time Behaviors of the Thermospheric O/N2 and NO Variations

Tuesday, 16 December 2014
Yongliang Zhang1, Larry J Paxton1, Daniel Morrison1, Hyosub Kil1,2 and Daniel Robert Marsh3, (1)The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States, (2)Johns Hopkins Univ, Laurel, MD, United States, (3)National Center for Atmospheric Research, Boulder, CO, United States
The thermospheric O/N2 column density ratio and nitric oxide (NO) column density are extracted from the TIMED/GUVI spectrograph data under sunlit conditions. The coincident O/N2 ratio and NO column density maps during a few geomagnetic storms reveal two major features: (1) Storm-time O/N2 depletion and NO enhancement extend from high to mid and low latitudes. They are anti-correlated on a global scale, (2) the NO enhancement covers a wider longitude and latitude region than O/N2 depletion on a local scale. The similarity between O/N2 depletion and NO enhancement on global scale is due to storm-time equatorward meridional wind that brings both O/N2 depleted and NO enhanced air from high to low latitudes. The altitude dependence of the storm-time meridional wind, different peaks altitudes of the local O/N2 and NO variations, and long life time of NO (one day or longer) may explain the different behaviors of O/N2 and NO on a local scale.