Time-series nighttime imagery for measuring the growth of Urban agglomeration in the Guangdong-Hong Kong-Macao Greater Bay Area

Abstract

This paper studies the structure and dynamics of urban agglomeration between 1992 and 2018 in one of most developed regions in China – the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) – based on the harmonized night-time light (NTL) data from the Defense Meteorological Satellite Program (DMSP) and Visible Infrared Imaging Radiometer Suite (VIIRS) imagery. We adopted Zipf's law as the rule to control the spatial clustering of adjacent lit pixels. The clustered pixels as patches are concentration of human activities and can then be used for regional urbanization analysis. Unlike conventional spatial units that are rarely changed, such as administrative boundaries, these patches change subtly each year and, more importantly, can help us to examine precisely the urbanization pattern in both development mode and intensity. We investigated the urban growth pattern during the 27-year timespan and conducted the analysis at both region and city levels. Interestingly, the results suggest that Zipf's law of derived patch sizes can hold nearly every year, showcasing the consistent spatial coherency of the urban agglomeration process in the entire region. The correlation between urbanization metrics for each city at three stages (1992–2000, 2000–2010, and 2010–2018) can further lead to deep insights towards the synergetic course of the coordinated and multi-center development.