MAPPING URBAN EXPANSION FROM LOCAL TO GLOBAL SCALES USING SATELLITE OBSERVATIONS

Satellite-based Earth observations with different spatiotemporal resolutions show a great potential to map urban expansion from local to global scales over past decades. In this study, we developed algorithms to map urban expansion at the local and global levels using nighttime light (NTL) and Landsat data and investigated temporal dynamics of urban extent. At the global level, we mapped urban extent dynamics from 1992 to 2013 at a 1km spatial resolution using the Defense Meteorological Satellite Program / Operational Linescan System (DMSP/OLS) NTL data. At the local level, we explored the feasibility of Landsat observations for continuous monitoring of urban expansion from 1985 to 2015 at a 30m spatial resolution in Ames and Des Moines, Iowa, US. Our results indicate that the NTL derived urban dynamics are informative for global urbanization studies, whereas the Landsat derived urban expansion reveals more details of environmental change related to the sprawl process. The new products of urban dynamics can serve as reliable datasets for analysis of spatiotemporal dynamics of urban areas at the local and global scales for their unique attribute of a spatially and temporally consistent definition of urban extent.