Estimation of Steel Stock in Building and Civil Construction by Satellite Images

Steel is the most widely used material in the world and numerous studies analyzing the material flow of steel have been conducted for Japan, Asia and the world. While top-down and bottom-up approaches have been employed in material flow analysis and steel stock accounting, the applicability of these approaches is largely dependent on data availability. To overcome this problem of limited data, we proposed a method for estimating steel stock based on satellite images. Previous studies have shown that satellite images of nighttime lights are closely correlated with human activities, such as electricity consumption, CO(2) emissions, and GDP, etc., which are also linked to the amount of steel stock. Therefore, in this study, images of nighttime lights were used in conjunction with land cover data to estimate the building and civil construction steel stock in Japan and other Asian countries. We initially performed the analysis for each prefecture of Japan and then applied the combined result to Japan, China, South Korea and Taiwan. Building steel stock was highly correlated with urban nighttime lights, while the steel stock used for civil construction structures was more closely correlated with total nighttime lights.