Urban environmental changes and its implications in the coupled human-nature system

Abstract:

Changes in urban environments play important roles in sustainable urban development. Satellite observations in fine spatial and temporal resolutions, together with new computer technologies, provide the possibility to monitor these changes across large geographic areas and over a long period. In this study, we developed new algorithms to characterize urban environmental changes including 2D and 3D urban extents, urban heat island, and urban phenology (i.e., onsets of green-up and senescence phases) and successfully implemented them on the advanced Google Earth Engine, a start-of-art platform for planetary-scale data analysis, mapping, and modelling for developing national and global products of these key indicators. The evaluation indicates that the proposed algorithms are robust and perform well in monitoring changes in urban environments. Using the developed products, we explored the implications of urban environment changes in the coupled human-nature system by investigating the responses of building energy use and vegetation phenology to these changes. We found urbanization leads to significant changes in urban environments and consequently affects the coupled human-nature system. The resulted products of urban extents, urban heat island, and phenology indicators from this study offer new datasets for relevant urban studies such as modeling urban sprawl over large areas and investigating responses of ecosystem and human activities to urbanization.