Mapping ambient light at night using field observations and high-resolution remote sensing imagery for studies of urban environments

Artificial lighting allows for a variety of activities to take place in the absence of sunlight, but also has an increasingly recognized range of negative social and health-related effects. For studies of urban ambient light at night (ALN), objective and standardized data on the amount of ALN experienced by people is often unavailable at the necessary intra-urban spatial scale. In this paper, we outline options for producing such data through (1) field observations acquired with a luminance meter mounted on a vehicle, (2) a 1-m resolution image mosaic produced from a dedicated aerial survey, and (3) a 50-m resolution image taken from the International Space Station. We produce two remote sensing-derived maps of ALN for a large urban area in Canada, and compare their spatial detail to the World Atlas of Artificial Night Sky Brightness, a publicly available alternative data source. Convergent validity with field observations suggests that both mapping approaches can be used to quantify the amount of light humans are exposed to at night, at different locations across a large urban area, and may thus aid in further studying the varied effects of artificial nighttime lighting.