<title>Light energy loss and its application to estimating global energy usage</title>

Abstract

We are now developing a system to estimate light energy loss to space using the US DMSP (Defense Meteorological Satellite Program) data and obtained many interesting results. The satellites have solar synchronous orbits with altitude around 800 km, and continuously obtain absolute (well-calibrated) flux ofterrestrial surface light. City light ejected to space is mostly energy loss because the light is not used to illuminate objects to be seen or decorated. The total amount of its energy loss in Japan estimated by us is an order of 20 billion yen (about 200 million US dollars). We are now estimating its loss for each cities (or areas) in Japan and in the world. Further, we found a possibility to estimate energy usage of each country after obtaining a clear relation between light energy loss and electric energy usage within different areas ofindividual electric companies in Japan. Therefore, we would like to conclude that our continuous estimation of city light from space are and will be creating a global information of energy usage.

Effects of light pollution revealed during a nocturnal aerial survey by two hyperspectral imagers

“…The total power emitted by artificial light sources is, on average, directly related to the overall energy consumption of the community. [1][2][3] The level of light pollution is therefore a general measure of how human activity modifies its environment, and hence is, although indirectly, an important parameter for monitoring and modeling all kinds of artificial pollution. This parameter is also relevant for economic investigations, because the amount of power ͑nocturnal light emission͒ that any country demands is strictly related to its gross domestic product.…”