The responses of the nightglow emissions observed by the TIMED/SABER satellite to solar radiation

Abstract

AbstractThe responses of four nightglow emissions, NO emission at 5.3 µm, O2 infrared atmospheric band at 1.27 µm, and OH emissions at 2.0 µm and 1.6 µm (referred to as OH2 and OH1 in this study), to solar radiation are studied and compared based on the data observed by the Sounding of the Atmosphere using Broadband Emission Radiometry instrument over 13 years. The quantitative relationships between the nightglow emissions and solar radiation are obtained by a linear regression fit using the F10.7 index. The intensities and the peak heights of the 13 year average global mean NO, O2, OH2, and OH1 nightglows are 270.0 ± 42.8 kR, 106.9 ± 2.2 kR, 133.2 ± 1.6 kR, 217.5 ± 2.4 kR, 123.6 ± 0.2 km, 89.8 ± 0.05 km, 88.1 ± 0.02 km, and 86.6 ± 0.02 km, respectively. Among the four nightglow emissions, the influence of solar radiation on the ones at lower heights is weaker than the ones higher above. The responses of the global mean NO, O2, OH2, and OH1 nightglow intensities to solar radiation are 176.3 ± 4.8%/100 solar flux units (sfu), 22.2 ± 1.4%/100 sfu, 12.9 ± 1.1%/100 sfu, and 11.4 ± 1.3%/100 sfu, respectively. The intensities and peak emission rates of the four global mean nightglow emissions are highly correlated to solar radiation. The response of the height of the global mean O2 nightglow peak emission rate to solar radiation is 0.51 ± 0.08 km/100 sfu. The responses of NO, OH2, and OH1 nightglow peak heights to solar radiation are not obvious. In addition, the responses of nightglow emissions to solar radiation change with latitude.