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Night on Earth: Mapping decadal changes of anthropogenic night light in Asia [1]

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Date: 2013-06-01  

The defense meteorological satellite program (DMSP) operational linescan system (OLS) has imaged emitted light from Earth's surface since the 1970s. In 1992 a digital archive was established for DMSP-OLS data at the NOAA National Geophysical Data Center. Annual composites of temporally stable night light have been processed and distributed by the NGDC for every year since 1992. Temporal overlap in the missions of multiple OLS sensors allows for intercalibration of the 30 annual composites over the past 19 years (Elvidge et al., 2009). These data offer the opportunity to quantify a unique spatiotemporal signature of human settlement growth and evolution. Here we summarize some initial results of a spatiotemporal analysis of annual change in the extent, distribution and intensity of anthropogenic night light in Asia.

The objective of this study is to quantify apparent changes in the number, extent and brightness of stable night lights in Asia. We limit the geographic scope of this study to Asia because this is where we observe the greatest changes. The intention is to illustrate a methodology for characterization and vicarious validation of apparent changes in areas where anthropogenic changes are large enough to be clearly distinguished from other types of change related to sensor calibration and atmospheric effects. The first part of the study illustrates the use of the principal component (PC) transformation and empirical orthogonal function (EOF) analysis with multi-temporal night light data. Background and details of the EOF analysis are given by Small (under review). Here we present the results of the EOF analysis and discuss the spatiotemporal changes quantified by the analysis. The second part of the study presents a vicarious validation of changes in night lights using changes in land cover as imaged by Landsats 5 and 7. The third part of the study presents spatial and temporal variations in the area, number and rank size distributions of lighted areas and discusses the implications for urban growth processes.

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[1] Url: http://www.sciencedirect.com/science/article/pii/S030324341200044X

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