Decades of NASA Satellite Data Reveals the Elusive, Enigmatic βUrban Pulseβ of Six Major Cities
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 βUrban Pulse.β
The research team behind the novel urban activity metric said that monitoring a cityβs 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 βNot Doing Wellβ
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 βoutcome of urbanization,β 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, βyou donβt really see the dynamics within an urban area.β
According to a statement detailing the new approach, a cityβs 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 βif and where their city is not doing well.β
βThis would allow (authorities) to be proactive rather than conducting a metaphorical autopsy after the decay of an area is evident,β 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 βdecades of dense time-series dataβ collected by NASAβs Harmonized Landsat and Sentinel-2 (HLS) Β satellites for physical transformations in an urban environment, such as new construction, measurable infrastructure improvements, and demolition.
Instead of analyzing each cityβs changes manually, the team evaluated the above changes on what they called βthe neighborhood levelβ 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 βhigh-frequency rhythms of developmentβ from a broad βouter spaceβ perspective, their approach βbridges the gap between abstract urban theories and measurable, real-world data.β

After examining CAPESβ 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 βabrupt, intense, and episodic bursts of construction.β
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 βdramatic boom-and-rest cyclesβ of expansion and dormancy that donβt appear to follow predictable annual seasons.
The third pattern revealed by measuring the six citiesβ Urban Pulse from space was that cities are βasynchronous,β meaning a single city does not βbeatβ in unison. The team noted that neighborhoods βpulse at completely different times.β When it functions properly, this βuncoordinated rhythmβ helps prevent the cityβs infrastructure and labor markets from βoverheating.β
Unlike previous methods for tracking a cityβs evolution, the team noted that their Urban Pulse approach can help researchers βvisualize a cityβs reaction to global shocks.β For example, the team said that their analysis captured βthe exact moment the COVID-19 pandemic triggered a widespread, synchronized βcardiac arrestβ in urban development worldwide.β
However, their new tool also revealed what the researchers termed βprofound inequalitiesβ 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 βdipsβ in activity, followed almost immediately by βrapid, policy-driven rebounds.β However, the same Orban Pulse analysis showed that the reactions in Mumbai and Mexico City were much more βmuted.β
βItβs like in human beings,β Zhu explained. βWhen you get a disease, itβs not going to show up exactly the same in different people.β
A βVery Impactful Toolβ 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 βit serves as an early warning system.β
βBy 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,β they explained.
The team also suggested that making Urban Pulse data publicly available could βrevolutionize how everyday people interact with their cities.β For example, an urban family considering a move to a new city or a new part of their current city could track a target neighborhoodβs 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.
βThis 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,β Zhu explained.
In a recent study, βThe Urban Pulse: Diagnosing the urbanization process as spiky, cyclical, and asynchronousβ was published in theΒ 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.