Assessing Light Pollution in China Based on Nighttime Light Imagery

Wei Jiang,Yuan Ni,Ruiqi Ma,Tengfei Long,Guojin He,Chen Wang

doi:10.3390/rs9020135

Abstract

Rapid urbanization and economic development inevitably lead to light pollution, which has become a universal environmental issue. In order to reveal the spatiotemporal patterns and evolvement rules of light pollution in China, images from 1992 to 2012 were selected from the Defense Meteorological Satellite Program Operational Linescan System (DMSP/OLS) and systematically corrected to ensure consistency. Furthermore, we employed a linear regression trend method and nighttime light index method to demonstrate China’s light pollution characteristics across national, regional, and provincial scales, respectively. We found that: (1) China’s light pollution expanded significantly in provincial capital cities over the past 21 years and hot-spots of light pollution were located in the eastern coastal region. The Yangtze River Delta, Pearl River Delta, and Beijing–Tianjin–Hebei regions have formed light pollution stretch areas; (2) China’s light pollution was mainly focused in areas of north China (NC) and east China (EC), which, together, accounted for over 50% of the light pollution for the whole country. The fastest growth of light pollution was observed in northwest China (NWC), followed by southwest China (SWC). The growth rates of east China (EC), central China (CC), and northeast China (NEC) were stable, while those of north China (NC) and south China (SC) declined; (3) Light pollution at the provincial scale was mainly located in the Shandong, Guangdong, and Hebei provinces, whereas the fastest growth of light pollution was in Tibet and Hainan. However, light pollution levels in the developed provinces (Hong Kong, Macao, Shanghai, and Tianjin) were higher than those of the undeveloped provinces. Similarly, the light pollution heterogeneities of Taiwan, Beijing, and Shanghai were higher than those of undeveloped western provinces.

Highlights

Light pollution was first identified by astronomers in the 1930s [1]
The standard deviation of night lights (SDNL) of Tibet had the fastest growth of up to 219%, followed by Yunnan, with 156%. These results show that the light pollution imbalance among undeveloped provinces increased during the study years
Hebei urban agglomeration have formed a light pollution stretch area and the spatial connectivity of light pollution in the Yangtze River Delta and Pearl River Delta is more obvious than that of the Beijing, Tianjin, and Hebei urban agglomeration. This result is consistent with the findings described widely used total night light (TNL) index, we developed three nighttime light indices to quantitatively assess the light pollution across the national, regional, and provincial scales, respectively

Summary

Introduction

Light pollution was first identified by astronomers in the 1930s [1]. Nowadays, it has become a widely discussed environmental issue following water pollution, air pollution, and noise pollution [2].In 2001, 19% of the global land area suffered from light pollution, which is higher than the thresholdRemote Sens. 2017, 9, 135; doi:10.3390/rs9020135 www.mdpi.com/journal/remotesensingRemote Sens. 2017, 9, 135 value, and 21% of the world’s population are living in light-polluted environments [3]. Light pollution was first identified by astronomers in the 1930s [1]. Nowadays, it has become a widely discussed environmental issue following water pollution, air pollution, and noise pollution [2]. Since the Chinese government implemented reform and the opening-up policy, unprecedented urbanization has taken place across the country, resulting in huge power consumption and a large number of cities with lights turned on all night. These places are referred to as ‘sleepless cities’.

Methods

Results

Discussion

Conclusion