Change Detection in Satellite Observed Nighttime Lights: 1992-2003

NOAA´s National Geophysical Data Center has developed a time series of annual global nighttime lights products at approximately 1 km resolution extending from 1992 to 2003. These products are cloud-free composites which have been processed to remove ephemeral lights from events like fires and background noise. Because the OLS has no on-board calibration an empirical approach was used to inter-calibrate the composites. In the inter-calibrated set it is possible to observe both expansions and contractions of lights. Many cities show rims of growth in lighting at their margins. The expansion of dim lighting detection into rural areas and smaller settlements occurred in many parts of the world. Contraction of lighting occurred in sections of the Former Soviet Union. More subtle declines in the brightness of lighting are detected in skyglow surrounding large cities, perhaps as the result of changes in lighting type and improvements in light fixtures.