Exploring Urban Precipitation Anomalies: The Influence of Local Climate and Urban Development

With urbanization continuing to reshape landscapes, understanding its impact on weather patterns is crucial. Although prior studies have explored urban-induced precipitation, none have offered a global perspective. This research is the first global analysis of urban precipitation anomalies for over one thousand cities worldwide. We find that urban precipitation anomalies are unequal across continents and climates. Over 60% of the global cities and their downwind regions show urban precipitation enhancements. Compared to cold and dry climates, cities in hot and humid climates are more likely to have large magnitudes of urban precipitation anomalies. Urbanization can amplify the urban precipitation enhancement, as the cities with larger populations, more apparent urban heat island effect, and higher aerosol load show a more obvious urban wet island effect. This research maps global urban precipitation anomalies and lays the foundation to consider urbanization as a factor in future scenarios beyond large-scale climate change, which will help to project extreme precipitation in urban areas and develop more resilient cities of the future.