A comparative study of urban expansion in Beijing, Tianjin and Shijiazhuang over the past three decades

• We mapped and compared urban land expansion in the Jing-Jin-Ji Urban Agglomeration.
• Beijing, Tianjin and Shijiazhuang demonstrated different urban growth patterns.
• The composition of urban growth type varied with city and time.
• Landscape responses to urban expansion changed at different scales.
• A considerable regional disparity in urban expansion magnitude and speed was observed.

Detailed comparative studies on spatiotemporal patterns of both urbanized area and urban expansion over a relatively long timeframe are rare. Here, we compared spatiotemporal patterns of urbanization in three major cities (i.e., Beijing, Tianjin and Shijiazhuang) in the Jing-Jin-Ji Urban Agglomeration using multi-temporal Landsat MSS, TM, and ETM+ images data of circa 1980, 1990, 1995, 2000, 2005 and 2010 integrated with Geographic Information System (GIS) techniques and landscape analysis approaches. A multi-scale analysis on the landscape responses to urban expansion from regional landscape to city and within city levels was performed. Results showed that urban area in Beijing, Tianjin and Shijiazhuang has expanded from 801 km2, 795 km2 and 682 km2 to 2452 km2, 3343 km2 and 1699 km2, increasing annually at 3.7%, 4.7% and 3.2%, respectively. Spatially, Beijing, Tianjin and Shijiazhuang have presented a mononuclear concentric polygon pattern, a double-nucleated polygon-line pattern, a sectorial point pattern, respectively, resulting primarily from their respective topographic constraints as well as urban planning and policy. Landscape responses to urban expansion varied with time and scale investigated, suggesting a general understanding on landscape metrics at regional or city level may fail to reveal detailed within city landscape dynamics under the impacts of urban expansion. The Jing-Jin-Ji Urban Agglomeration faces a great challenge to manage trades-offs between narrowing down intra-regional disparity and maintaining regional economic and ecological benefits.