Cloud coverage acts as an amplifier for ecological light pollution in urban ecosystems

Area of Science:

• Environmental Science
• Ecology
• Astronomy

Background:

• The diurnal light-dark cycle is a crucial environmental cue for Earth's ecosystems.
• Artificial light at night (ALAN) from urban areas causes ecological light pollution, disrupting natural cycles and affecting organism behavior.
• Factors amplifying sky luminance may intensify ecological light pollution.

Purpose of the Study:

• To investigate how cloud coverage affects sky luminance and ecological light pollution.
• To quantify the amplification of sky glow under different weather conditions and distances from urban centers.

Main Methods:

• Measurements of sky luminance were taken.
• Analysis was conducted for locations within a city and at varying distances from it.
• Comparison of sky luminance during overcast and clear nights, including moonlit conditions.

Main Results:

• Cloud coverage was found to dramatically amplify sky luminance.
• Sky luminance increased by a factor of 10.1 within Berlin and 2.8 at 32 km from the city.
• Overcast nights in the city were 4.1 times brighter than clear, moonlit rural nights.

Conclusions:

• Cloud cover significantly intensifies ecological light pollution.
• Urban ALAN is amplified by weather, with implications for chronoecological studies.
• The amplification effect of light pollution under cloudy conditions needs to be considered in urban ecological research.