NASA-Backed Research Introduces 'Urban Pulse' Method to Track City Growth from Space

A recent study published in PNAS by researchers including Zhe Zhu and Karen Seto outlines an "Urban Pulse" framework to track urban change over time using satellite data. Rather than relying on static before-and-after snapshots, the method uses Harmonized Landsat and Sentinel-2 (HLS) data combined with deep learning to measure construction activity across neighborhoods.

Tracking the Rhythm of Urbanization

The research team applied the Classify Areas with Potential and then Exclude the Stable pixels (CAPES) method to study six cities: Dubai, Lagos, Mexico City, Mumbai, Seattle, and Shenzhen. By analyzing high-frequency observations captured every two to three days, the researchers tracked fine-grained physical changes such as construction, infrastructure improvements, repairs, and demolition.

Key findings from the study include:

• Episodic Growth: Urbanization unfolds in cycles of expansion, stabilization, and decline rather than continuous linear progression.
• Asynchronous Neighborhoods: Different parts of the same city change independently, with construction spikes occurring at different times across neighborhoods.
• System Shocks: The data reflected broader disruptions, showing a synchronized dip in construction activity around the COVID-19 pandemic followed by varied local recovery rates.

Practical Implications for City Planners

Researchers suggest that monitoring neighborhood-level pulses could eventually help planners detect early signs of infrastructure strain, economic stagnation, or environmental vulnerability. Because citywide averages can mask local disparities, high-temporal-resolution data could assist officials in identifying areas that require closer investigation or targeted infrastructure upgrades.

Readers can verify these findings by reviewing the published study by Zhu et al. (2026) in *Proceedings of the National Academy of Sciences* (PNAS) or exploring ongoing Earth observation initiatives through the NASA/USGS Landsat program and the Harmonized Landsat and Sentinel-2 project.