Research on the influence of weather conditions on urban night light environment

The increasingly serious urban light pollution has deepened the relevant research, and weather conditions indeed have great impact on the urban night light environment. Based on the SQM instrument, fish-eye camera and weather-related systems, this paper analyzes the changing law of night sky with time and weather. The brightness of the typical clear night sky changes regularly with time, and mainly includes five phases: rapid decline phase, slow decline phase, unstable decline phase, smooth phase, and rapid increase phase of sky brightness. In two phases of the smooth sky brightness, the average sky brightness in the high and low brightness phase respectively is 18.123 mag/arcsecond(2) and 18.82 mag/arcsecond(2), and about 15 times and 8 times higher than those of the natural night sky. This paper establishes the regression model of typical clear night sky brightness in rapid decline phase and rapid increase phase of sky brightness. The sky magnitude brightness in rainy weather is much lower than that in clear weather, the difference is about 3 mag/arcsecond2, the brightness can be reach 15.63 mag / arcsecond(2); the average magnitude brightness in snowy days is about 0.17 mag/arcsecond(2) higher than that in cloudy weather. There is a significant correlation among the air quality index, the ground illumination ratio of moon, the atmospheric visibility and the sky brightness. The deepened air pollution can also intensify light pollution, which can increase to 3 and 10 times higher than the night sky brightness under the moderate and severe air pollution. The lunar cycle has the least impact on light pollution in clear days, the sky brightness with the full moon is about 2 and 3 times higher than that without the moon.