Satellite observations detect ‘urban pulse’ of six global cities

Cities behave like living organisms, exhibiting growth spurts, transformations, and even decay. Researchers have now captured this dynamic behavior in six major global cities, Dubai, Lagos, Mexico City, Mumbai, Seattle, and Shenzhen, by tracking their "urban pulse" using satellite imagery.

This novel approach moves beyond traditional methods that rely on infrequent, aggregated data like yearly censuses or decade-long footprint maps. According to study lead author Zhe Zhu, a professor at the University of Connecticut, the "urban pulse" is inspired by the human pulse, offering insights into a city's health and development processes. "The urban pulse measures the high-frequency process of development, and therefore we can spot early warning signs of economic stress or stagnation before they become full-blown crises," Zhu explained.

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We got the inspiration from the human pulse, which tells us ​different information about our health than weight or height. The urban pulse measures the high-frequency process of development, and therefore we can ​spot early warning signs of economic stress or stagnation before they become full-blown crises.

The study, published in the journal Proceedings of the National Academy of Sciences, highlights that urbanization is not a uniform process. Senior author Karen Seto, a Yale University professor, noted that development is often "spiky," occurring in intense bursts, or "cyclical," with boom-and-rest phases. Furthermore, different neighborhoods within the same city can develop at completely uncoordinated times, a phenomenon described as "asynchronous."

Utilizing high-frequency satellite imagery from NASA and the European Space Agency, the researchers tracked physical changes such as new construction, demolitions, infrastructure improvements, and expansion into green spaces. The selected cities represent a diverse range of political and economic conditions, from the state-led development of Shenzhen to the market-driven growth of Seattle and the informal expansion of Lagos.

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Urbanization is actually ‘spiky,’ meaning that it happens in abrupt, intense bursts, or ‘cyclical,’ moving through boom-and-rest phases that don’t match annual seasons, or ‘asynchronous,’ as different neighborhoods in the exact same city ​develop at completely different, uncoordinated times.