Monitoring the evolution of the anthropogenic light emissions is a priority task in light pollution research. Among the complementary approaches that can be adopted to achieve this goal stand out those based on measuring the direct radiance of the sources at ground level or from low Earth orbit satellites, and on measuring the scattered radiance (known as artificial night sky brightness or skyglow) using networks of ground-based sensors. The terrestrial atmosphere is a variable medium interposed between the sources and the measuring instruments, and the fluctuation of its optical parameters sets a lower limit for the actual source emission changes that can be confidently detected. In this paper we analyze the effect of the fluctuations of the molecular and aerosol optical depths. It is shown that for reliably detecting changes in the anthropogenic light emissions of order ∼1 % per year, the inter-annual variability of the annual means of these atmospheric parameters in the measurement datasets must be carefully controlled or efficiently corrected for.

中文翻译：

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检测人为光发射的变化：大气变化导致的限制


监测人为光发射的演变是光污染研究的一项优先任务。在为实现这一目标而可以采用的互补方法中，最突出的是那些基于测量地面或近地轨道卫星的光源的直接辐射，以及使用地面传感器网络测量散射辐射（称为人工夜空亮度或天光）的方法。陆地大气是介于光源和测量仪器之间的可变介质，其光学参数的波动为可以可靠检测的实际光源发射变化设定了下限。在本文中，我们分析了分子和气溶胶光学深度波动的影响。结果表明，为了可靠地检测每年 ∼1 % 的人为光发射变化，必须仔细控制或有效校正测量数据集中这些大气参数的年平均值的年际变化。