Abstract Daytime oxygen airglow emission rate variability provides us with a means of remote investigations of the upper atmospheric behavior. Dayglow emission rates typically show a diurnal pattern with a peak at around noon, especially during geomagnetic quiet conditions. The photochemical and empirical models show that the emission rates typically vary as a function of solar zenith angle (SZA) and solar flux. Thus, both, larger solar flux magnitudes and smaller solar zenith angles, contribute to larger dayglow emission rates as the yield of excited oxygen atoms is expected to be greater in those conditions. However, variability in the annual dayglow emission rates obtained from measurements at low-latitudes (Hyderabad, India; 170 N, 800 E; 8.70 N Mag. Lat.) and mid-latitudes (Boston, USA; 42.20 N, 710 W; 48.30 N Mag. Lat.) show different behavior with regard to solar flux variation. The variability in the low-latitude emission rate is primarily dependent on that of the solar flux. However, such primary dependence on the solar flux is not reflected on the emission rate variability seen over mid-latitudes. This discrepancy is understood to be due to the relative effects of solar flux and the globally changing compositional variability, characterized by the oxygen to molecular density ratios (O/N2), that show varying behavior from mid- to low-latitudes. Seasonal compositional variation due to transport processes is attributed to be the cause for the observed discrepancy which is also confirmed by independent satellite measurements. We also present an empirical model of O/N2 as a function of day of the year and latitude obtained using satellite based ultraviolet measurements to quantify the compositional variation.

中文翻译：

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太阳通量与成分变化对低纬度和中纬度白天氧光发射率变化的影响

摘要 白天氧气气辉排放率的变化为我们提供了一种远程调查高层大气行为的方法。日光发射率通常显示出昼夜模式，在中午左右达到峰值，尤其是在地磁安静条件下。光化学和经验模型表明，发射率通常作为太阳天顶角 (SZA) 和太阳通量的函数而变化。因此，较大的太阳通量大小和较小的太阳天顶角都有助于较大的白昼发光率，因为在这些条件下激发氧原子的产量预计会更高。然而，从低纬度（印度海得拉巴；170 N，800 E；8.70 N Mag. Lat.）和中纬度（美国波士顿；42.20 N，710 W；48.30 N Mag. 纬度 ) 在太阳通量变化方面表现出不同的行为。低纬度发射率的变化主要取决于太阳通量的变化。然而，这种对太阳通量的主要依赖并未反映在中纬度地区的排放率变化上。这种差异被认为是由于太阳通量和全球变化的成分变异性的相对影响，以氧分子密度比 (O/N2) 为特征，表现出从中低纬度变化的行为。由于运输过程引起的季节性成分变化被认为是观察到的差异的原因，独立卫星测量也证实了这一点。