The influences of temperature and meridional neutral wind on 630.0 nm nightglow

Tuesday, 16 December 2014
Chih Yu Chiang, Wing Yee Sunny Tam and Tzu-Fang Chang, NCKU National Cheng Kung University, Tainan, Taiwan
A number of recent studies have highlighted the observational evidence of a coupling between temperature and neutral wind to study the midnight brightness of 630.0 nm nightglow, which is usually related to midnight temperature maximum (MTM) effect. Thus, in this study, we calculate the volume emission rate of the 630.0 nm nightglow to investigate the influence of neutral temperature and meridional neutral wind. We utilize the SAMI2 model which involves the Mass Spectrometer Incoherent Scatter model (MSIS) and the Horizontal Wind Model (HWM) to simulate the charged and neutral species at 630.0 nm nightglow emission layer. The result shows that the neutral wind is more efficient to affect the emission rate of nightglow than temperature. It is found that a returning point shows up as the temperature changes. A returning point means the production rate of OI(1D) approximates to the loss rate of it. From the observations by ISUAL payload onboard the FORMOSAT-2 satellite, we frequently find the similar patterns during the selected seasons. Through the studies, it is also found the emission rate of OI(1D) could be expressed by the ratio [O+][O2]/[O].