Zhe Zhu And Karen C. Seto Measure Cities’ Urban Pulse Using NASA Landsat And Sentinel-2

Researchers led by University of Connecticut Professor Zhe Zhu and senior author Karen C. Seto developed the “Urban Pulse” framework to measure, monitor, and manage cities as a dynamic process rather than a static snapshot.

“People often speak metaphorically of the heartbeat or pulse of a city, but according to the authors of a new paper published in the Proceedings of the National Academy of Sciences, cities do indeed have an “urban pulse”—an indication of urban “metabolic activity” that can be measured to suss out telltale patterns”

Ars Technica

The method uses dense time-series data from NASA’s Landsat and the European Space Agency’s Sentinel-2 satellites to track construction activity and intensity at the neighborhood scale across six cities: Seattle, Shenzhen, Lagos, Mumbai, Dubai, and Mexico City.

Ars Technica

Seto said, “Treating a city as a static snapshot is akin to diagnosing a patient based on a single heartbeat,” and she added that “The Urban Pulse framework changes how we understand, monitor, and manage the world’s cities.”

The team’s metric, Capital Infrastructure and Real Assets (CIRA), is designed to render “invisible city-wide dynamics visible” by tracking construction and related changes over time.

In the study’s framing, “Cities do not grow smoothly or continuously,” with development defined by “sharp, short-lived spikes and episodic surges, punctuated by long periods of baseline quiet.”

The Urban Pulse approach describes three “vital signs” that characterize urbanization patterns, including that cities are “spiky,” “cyclical,” and “asynchronous.”

Zhu said, “For decades, we had just been capturing the outcome of urbanization—a house that’s been built, or a road expansion,” but the framework aims to show “the dynamics within an urban area.”

EurekAlert!

Ars Technica reports that the authors define urbanization as “processes of concurrent change in at least six dimensions, including demography, economy, infrastructure, environment, governance and culture,” which “give rise to outcomes” such as “population growth, urban land expansion, GDP growth, and innovation.”

In the satellite-derived analysis, neighborhoods go through “dramatic boom-and-rest cycles” that do not follow predictable annual seasons, and different neighborhoods “pulse at completely different times.”

EurekAlert! adds that the team’s data captured “the exact moment the COVID-19 pandemic triggered a widespread, synchronized ‘cardiac arrest’ in urban development worldwide.”

Beyond academia, the researchers say Urban Pulse monitoring can help governments, urban planners, and environmentalists intervene before crises become entrenched by identifying early signs of urban decay or unsustainable sprawl.

“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 Debrief

The Debrief quotes the team explaining, “This would allow (authorities) to be proactive rather than conducting a metaphorical autopsy after the decay of an area is evident,” and it describes the tool as “an early warning system.”

EurekAlert! similarly frames the method as a diagnostic tool, saying “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.”

The researchers also argue that making Urban Pulse data publicly available could “revolutionize how everyday people interact with their cities,” including for an urban family considering a move to a new city or a new part of their current city.

Ars Technica adds that the “urban pulse” could be checked while “house-hunting” or while scouting potential locations for a new business, tying the satellite metric to “top-down policy decisions from governments” and “bottom-up decisions from everyday people.”