Model Study of Peak Emission Rate of Atomic Oxygen Redline Dayglow Emission

A comprehensive model featuring volume emission rate and solar flux is developed to study the 630.0 nm redline dayglow emission in the earth's thermosphere. The present model is tested by using available WINDII data. The modeled peak emission rates are found in good agreement with WINDII measurements (within 15 percent). The peak emission rate (Vp) of redline dayglow emission is studied under high solar activity conditions. It has been found that the diurnal variation of peak emission rate with respect to the peak emission rate at equator (Vp(eq)) shows a dip at the equator and a peak between 15° and 30° latitudes in both the hemispheres. The non-smooth variation of the ratio Vp/Vp(eq) between both the hemispheres is explained on the basis of variation of electron density in the thermosphere. The present model is further used to study the seasonal variation of peak emission rate of redline dayglow emission. The seasonal variation of the ratio Vp/Vp(eq) shows an asymmetry between both the hemispheres at various local times. The annual asymmetry index is introduced for peak volume emission rate of redline dayglow emission. The overall study of annual asymmetry index shows that the ratio Vp/Vp(eq) is always higher in northern hemisphere than in southern hemisphere at different local times.