PNAS has an article relating GDP with luminosity: summarized in ScienceNOW Bright Lights, Rich Cities:
In the hope of finding an alternative means of measuring GDP, macroeconomists Xi Chen and William Nordhaus of Yale University turned to nighttime images of the globe taken by U.S. Air Force satellites. They overlaid a grid on these high-resolution images and measured the amount of light, or radiance, emanating from each cell. For countries that already provide economic information widely considered trustworthy, brighter radiance in a given region correlated tightly with a higher GDP in that region, the researchers report online today in theProceedings of the National Academy of Sciences. Using this data, the economists built a statistical model, correcting for certain variables such as location on a continent (reflections on large bodies of water can distort satellite images) and distortion of the image by the atmosphere, that then allowed them to estimate the GDP for countries with unclear economic status.