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Enhanced Vegetation Growth in the Urban Environment Across 32 Cities in the Northern Hemisphere

How the urban environment influences vegetation phenology is important to understand the living environment and the climate‐vegetation interaction. This study investigates changes in vegetation phenology in the urban environment using remote sensing data for 32 major cities in the Northern Hemisphere. Vegetation phenological information for both urban and rural areas of each individual city was derived from the remote sensing data. We found that the urban environment generally enhanced vegetation growth but at varied degrees for different regions in the Northern Hemisphere. Vegetation phenology metrics, including the start of season (SOS), the end of season (EOS), and the growing season length (GSL), have large differences between urban and rural environment. Vegetation SOS in urban areas occurred earlier than in rural areas for 22 in 32 cities, and the relationships between advanced urban SOS and the distance away from urban centers are significant for 9 cities. Vegetation EOS in urban areas occurred later than in rural areas for 19 in 32 cities, and the relationships between delayed urban EOS and the distance away from urban centers are significant for 10 cities. The response of SOS to the urban environment is found dependent upon the latitude of urban centers and urban spring daytime and nighttime temperatures. Analysis on ground observational records of vegetation phenology in the region of North America supports the findings derived from remote sensing data. These findings could help to understand the impacts of the urban environment on vegetation growth.