Abstract: With the continuous development of society, coordinating urbanization with the ecological environment has become a critical challenge for sustainable regional development. This study aims to advance the understanding of spatial heterogeneity in the coupling coordination between urbanization and ecological environment using time-series remote sensing technology, a departure from traditional statistical data analysis. Specifically, we developed a composite nighttime light index (CNLI) to spatially represent urbanization levels and a time-series remote sensing ecological index (ts-RSEI) to assess ecological conditions. By combining quadrant analysis with the coupling coordination degree (CCD) model, we examined the urbanizationecological environment relationship in the coastal urban belt of the Yangtze River Delta during 1992-2021. The results showed that: (1) Shanghai consistently exhibited the highest level of urbanization, driving the urbanization development in neighboring cities, especially in the southern delta. (2) Ecological degradation displayed a bimodal distribution, with significant declines in cities between Shanghai and Zhoushan. (3) Overall, the coupling coordination between urbanization and the ecological environment shifted from the second quadrant to the fourth quadrant. The CCD followed an “inverted U-shaped” trend, increasing from 0.356 to 0.684 and then decreasing to 0.432. Spatially, the coupling coordination between urbanization and the ecological environment in Shanghai and its surrounding cities (e.g., Nantong, Jiaxing, Ningbo, Zhoushan, and Taizhou) shifted from the regional peak in the 1990s to the regional trough in the 2020s, and the downward trend gradually slowed down after 2015. In contrast, cities in the northern and southern delta (e.g., Lianyungang, Yancheng, and Wenzhou) as well as their suburban areas gained an advantage in the coupling coordination between urbanization and ecological environment. This pattern of spatially heterogeneous development is closely linked to the allocation of natural resources and policy-driven urban infrastructure optimization.

Key words: coupling coordination relationship, urbanization, ecological environment, time-series remote sensing, Yangtze River Delta