Radiative cooling due to NO at 5.3

The effect of geomagnetic storms on the peak emission of NO Volume Emission Rate (NO VER) at 5.3 m, in mesosphere and lower thermosphere (MLT) region, is studied over the Asian sector during 26\textendash29 September 2011 (storm 1) and 18\textendash21 February 2014 (storm 2). The data for peak emission of NO VER is obtained from SABER instrument onboard the NASA\textquoterights TIMED satellite. The SABER retrieved data along with the neutral densities obtained from NRLMSISE-00 model have been used to study the latitudinal and longitudinal variation of peak NO VER during the storm period. The variations induced in the peak emission of NO VER is understood with the help of fluctuations in neutral species and the resulting changes in chemistry. It has been found that the peak emission of NO VER is strongly influenced by the storm conditions. The peak emission of NO VER at 5.3 m is found to be maximum at higher latitudes during the storms. However, the magnitude of peak NO VER gradually decreases towards the equator during the storms. The modeled atomic oxygen number density shows depletion at the higher latitudes corresponding to peak altitude of NO VER. There is a negative correlation between the peak emission of NO VER and Dst index during the main phase of the storm. The peak emission of NO VER and modeled atomic oxygen number density shows the positive correlation at the equator region, while negative correlation at the higher latitudes. At higher latitudes modeled atomic oxygen number density shows positive correlation with Dst index, while negative correlation at the equator. The correlation factors obtained between various parameters related to the storm time radiative cooling strongly support the existing understanding of the variation of NO VER during extreme space weather events.