Spatiotemporal Mechanisms of Mountainous Urban Expansion Using Nighttime Lighting Remote Sensing—The Case of Guizhou

Abstract

Nighttime light remote sensing has provided valuable insights into the spatiotemporal development of mountain cities across the karst area. Taking Guizhou as the study case, this study integrates DMSP/OLS and NPP/VIIRS nighttime light data from 1992 to 2022. The optimal threshold for identifying urban areas was determined through conventional data analysis. The extent of built-up areas across eight distinct periods was extracted to examine the spatiotemporal characteristics of mountain cities. The results revealed the following: The urban area of Guizhou has consistently expanded over the past three decades, with the rate and intensity of this growth following an M-shaped fluctuation pattern. The expansion rates of prefecture-level cities were categorized into four types: stable, fluctuating, breakthrough, and gradual. This urban growth predominantly followed a northeast-southwest axis. Guiyang has long served as the urban core of Guizhou, with the core shifting 42.03 km to the northeast over this period. Urban expansion exhibited three primary patterns: ring-like, linear (axial), and punctate. Notably, ring-like expansion was marked by a hollow annulus, while linear (axial) expansion mainly occurred along river valleys near smaller tributaries. The urban core of Guizhou evolved in distinct phases. Initially, Guiyang was the sole micro core, later developing into the primary core. Ultimately, a hierarchical urban structure emerged, with Guiyang as the main core, Zunyi as a secondary core, and a constellation of Kaili, Duyun, and Fuquan Cities forming peripheral micro cores. This system was characterized by Guiyang’s influence over Anshun and the decentralized growth of other cities. These findings offer important insights for urban planning and territorial development in mountain cities, such as those in Guizhou.