Monitoring bidecadal development of urban agglomeration with remote sensing images in the Jing-Jin-Tang area, China

As an important urban agglomeration of China, the Jing-Jin-Tang area has experi- enced intense urbanization since the 1980s. This study explores the spatiotemporal dynamics of urban areas in this region using multitemporal Landsat images. An enhanced built-up (BU) index method was applied to extract BU areas with an overall accuracy ranging from 75% to 91.35%. Seven spatial metrics were used to discern urban growth patterns at city and county levels. The results indicate that all cities witnessed a rapid growth of BU areas with different spatial patterns. Beijing has been aggregating since the 1990s and a large homogeneous urban patch has formed. The construction and development of metropolitan Beijing and Tianjin started in the early 1980s and became almost fully developed by the end of 1990. Tangshan, like many medium-sized cities in China, is still enduring a development process with an accelerating pace. The metropolitan areas of Beijing and Tianjin have been greatly developed with BU densities exceeding 90% since 2000, compared with Tangshan's 55% in 2010. These results provide spatial information on the evolution of urban extent in the period of 1990s to 2010s in this region. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original pub- lication, including its DOI. (DOI: 10.1117/1.JRS.8.084592) The Beijing-Tianjin-Tangshan (a.k.a. Jing-Jin-Tang) urban agglomeration is mainly com- posed of three adjacent cities: Beijing, Tianjin, and Tangshan in northern China. It is located at the heart of the Bohai Economic Rim, and plays a vital role in the nation's economic growth. 3 This area has experienced intense urbanization since the national economic reform of the late 1980s. The rapid growth of built-up (BU) areas has brought great pressure to local environment and has led to serious environmental problems such as water shortage, air/water pollution, and vegetation degradation, especially in overpopulated areas. Air pollution results in significant neg- ative health impacts on the large population in cities like Beijing. 4 Dumping solid waste on the