Cities may not be living things, but they behave a lot like them — growing, changing, and sometimes declining in ways that mirror biological processes. Now, a team of researchers has used satellite imagery to monitor the vital signs of six major cities across the globe, identifying what they call a distinctive “urban pulse” unique to each one.
The six cities studied were Dubai, Lagos, Mexico City, Mumbai, Seattle, and Shenzhen. Scientists developed a new approach to document changes happening in each city in near real-time, offering a far more detailed picture than traditional methods have allowed.
For years, experts have tracked urban growth using data collected infrequently — things like annual census figures, yearly economic reports, or decade-long maps showing how a city’s boundaries have shifted. But the researchers behind this new study argue that approach leaves out crucial details about how cities actually develop.
“We got the inspiration from the human pulse, which tells us different information about our health than weight or height,” said study lead author Zhe Zhu, a professor of remote sensing and director of the Global Environmental Remote Sensing Laboratory at the University of Connecticut’s Department of Natural Resources and the Environment.
Zhu explained that the urban pulse concept goes beyond simply recording end results. “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,” he said. “We compare traditional metrics to looking at a heart attack — the outcome — whereas the ‘urban pulse’ is like monitoring the daily lifestyle and vital signs leading up to that heart attack — the process.”
The study’s central finding, published in the journal Proceedings of the National Academy of Sciences, is that urban growth is far from smooth or predictable. Study senior author Karen Seto, a professor of geography and urbanization science at Yale University, described what the data revealed.
“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,” Seto said. “This is important because, for decades, researchers have characterized cities through static maps.”
To gather their data, the team relied on dense, high-frequency satellite imagery from NASA’s Landsat program and the European Space Agency’s Sentinel-2 satellites. They focused on physical changes such as new construction, demolition, major infrastructure upgrades, and development spreading into green spaces.
“We selected cities with a wide range of political-economic conditions including the state-led development of Shenzhen, the market-driven growth of Seattle, the informal expansion of Lagos and the megaprojects of Dubai,” Zhu said.
Each city displayed its own distinct pattern. Shenzhen — once a small fishing village near Hong Kong that has grown into a massive metropolis — showed the highest levels of growth intensity, with large, clustered spikes reflecting rapid, government-directed development. Dubai also recorded enormous growth, but its pulse was more speculative in nature, driven by isolated, high-cost coastal megaprojects that surged and then stalled. Lagos, Nigeria’s largest city, had a highly fragmented pulse, with long quiet stretches broken up by short, intense bursts of activity. Seattle’s pattern reflected a market-driven cycle of redevelopment and increasing density.
Mumbai, India’s financial and commercial hub, and Mexico City, the most populous city in North America, stood out for their resilience — both showed far less disruption during global shocks like the COVID-19 pandemic compared to the other cities studied.
“Just as a human pulse reacts to illness, our data captured the exact moment COVID-19 triggered a synchronized ‘cardiac arrest’ in development worldwide. But the recovery was entirely unequal,” Zhu said.
He added: “Shenzhen saw a sharp, coordinated dip followed by a rapid rebound. Lagos experienced a muted pulse that transitioned into smaller, incremental changes. Meanwhile, cities like Mumbai and Mexico City showed much less of an impact. It showed us that global shocks don’t manifest the exact same way in every city’s ‘body.’”
The researchers believe their method has real-world applications for those managing urban areas. “For urban planners and policymakers, it functions as a diagnostic tool. Instead of reacting to a crisis after the fact, they can see exactly when and where a neighborhood’s ‘pulse’ is slowing down and intervene early to prevent infrastructure collapse or economic decay. It also prevents cities from overheating their labor and material markets,” Seto said.
