A multi-institutional team of researchers led by University of Connecticut Professor Zhe Zhu has developed a method for measuring the dynamic, real-time activity of urban environments from space, which they are calling an “Urban Pulse.”
The research team behind the novel urban activity metric said that monitoring a city’s Urban Pulse could help mitigate uncontrolled urban sprawl or decay and enable environmentalists and urban planners to intervene before disasters become unavoidable.
Measuring an Urban Pulse Could Reveal Neighborhoods ‘Not Doing Well”
Although environmentalists and urban planners have a wide range of tools to measure the activities within a city, Zhu notes that scientists have spent decades merely capturing the “outcome of urbanization,” such as a finished road or a newly completed home. However, the researcher and lead author of a study detailing the Urban Pulse methodology added that, even with all the current tools, “you don’t really see the dynamics within an urban area.”
According to a statement detailing the new approach, a city’s pulse is determined by all construction activity within it. Along with new construction, the metric includes repairs, infrastructure improvements, or expansion into previously undeveloped green spaces. When used correctly, the researchers said that it can help determine “if and where their city is not doing well.”
“This would allow (authorities) to be proactive rather than conducting a metaphorical autopsy after the decay of an area is evident,” the team explained.
Bridging the Gap Between Abstract Urban Theories and Measurable, Real-World Data
To test their approach, the team evaluated the Urban Pulse of six cities: Seattle, Shenzhen, Lagos, Mumbai, Dubai, and Mexico City. This involved a deep examination of what the team termed “decades of dense time-series data” collected by NASA’s Harmonized Landsat and Sentinel-2 (HLS) satellites for physical transformations in an urban environment, such as new construction, measurable infrastructure improvements, and demolition.
Instead of analyzing each city’s changes manually, the team evaluated the above changes on what they called “the neighborhood level” using a deep-learning and time-series-analysis approach called CAPES, developed by former UConn postdoctoral researcher Ji Won Suh. The team said that, by observing these “high-frequency rhythms of development” from a broad ‘outer space’ perspective, their approach “bridges the gap between abstract urban theories and measurable, real-world data.”
After examining CAPES’ results, the team found several key markers within the Urban Pulse. For example, the view from space revealed that growth within cities is not smooth and steady. Instead, Zhu and colleagues said that development happens in “abrupt, intense, and episodic bursts of construction.”
CAPES also revealed that the rhythms of an urban environment are cyclical. For example, while a city may show relatively steady growth on a broader level, individual neighborhoods go through “dramatic boom-and-rest cycles” of expansion and dormancy that don’t appear to follow predictable annual seasons.
The third pattern revealed by measuring the six cities’ Urban Pulse from space was that cities are “asynchronous,” meaning a single city does not ‘beat’ in unison. The team noted that neighborhoods “pulse at completely different times.” When it functions properly, this “uncoordinated rhythm” helps prevent the city’s infrastructure and labor markets from “overheating.”
Unlike previous methods for tracking a city’s evolution, the team noted that their Urban Pulse approach can help researchers “visualize a city’s reaction to global shocks.” For example, the team said that their analysis captured “the exact moment the COVID-19 pandemic triggered a widespread, synchronized ‘cardiac arrest’ in urban development worldwide.”
However, their new tool also revealed what the researchers termed “profound inequalities” in how individual cities recovered from the dramatic halt to urban growth. For example, the team said that the Urban Pulse of Shenzhen revealed synchronized ‘dips’ in activity, followed almost immediately by “rapid, policy-driven rebounds.” However, the same Orban Pulse analysis showed that the reactions in Mumbai and Mexico City were much more “muted.”
“It’s like in human beings,” Zhu explained. “When you get a disease, it’s not going to show up exactly the same in different people.”
A ‘Very Impactful Tool’ for Navigating Cities
Although the Urban Pulse metric offers a tantalizing tool for academics, the team noted real-world benefits for global policymakers, urban planners, and environmentalists, adding that “it serves as an early warning system.”
“By monitoring the rhythm, rate, and amplitude of neighborhood pulses, governments can identify early signs of urban decay or unsustainable sprawl and intervene before crises become entrenched,” they explained.
The team also suggested that making Urban Pulse data publicly available could “revolutionize how everyday people interact with their cities.” For example, an urban family considering a move to a new city or a new part of their current city could track a target neighborhood’s pulse to spot early warning signs of decay or early indicators of positive-trending growth. The same data could help business owners plan new locations or expanded service routes, depending on the business profile and the local Urban Pulse trends.
“This is going to be a very impactful tool influencing not only top-down policy decisions from governments but also bottom-up decisions from everyday people navigating their cities,” Zhu explained.
In a recent study, “The Urban Pulse: Diagnosing the urbanization process as spiky, cyclical, and asynchronous” was published in the Proceedings of the National Academy of Sciences.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.