Seattle and Portland, Oregon, are among the cloudiest cities in the United States. But that infamous cloud cover is no match for the U.S.-Indian Earth satellite NISAR (NASA-ISRO Synthetic Aperture Radar), which is designed to peer straight through clouds. Doing so allows scientists to study the Pacific Northwest’s natural landmarks and bustling port cities like never before.
Comparing the highly detailed imagery from the NISAR mission over time can reveal subtle changes in forests, wetlands, urban areas, and infrastructure. Radar images from the satellite — a joint effort between NASA and the Indian Space Research Organisation (ISRO) — can also detect subtle motions associated with volcanic activity, glacier movement, slips along faults, and slow-moving landslides.
“The Pacific Northwest is home to millions of people and supports major industries from tech and aerospace to agriculture and forestry,” said remote sensing technologist Brandi Downs of NASA’s Jet Propulsion Laboratory in Southern California, who helped process the NISAR imagery. “This recent imagery highlights how NISAR data can support resource management, natural-hazard monitoring, and environmental decision-making.”
Built by JPL, NISAR’s L-band radar uses microwaves that can pass uninterrupted through clouds and, thanks to its 39-foot (12-meter) antenna reflector, provides a high level of detail for anyone who wants to understand how a region’s surface and natural resources are changing. These radar signals, sent toward the Earth’s surface, are reflected off the ground and back to the spacecraft, a phenomenon called backscatter. By measuring changes in the reflected signal, scientists can identify properties on the surface like moisture, vegetation, and variations in terrain.
Radar images don’t capture true color the same way photographs do. Instead, the colors seen here represent different combinations and intensities of radar signals or their orientation. The latter is called polarization.
Captured Nov. 10, 2025, the Pacific Northwest imagery shows the waterways around Portland and Seattle, with the roadways and cityscapes built alongside them. Some of these areas are dotted in magenta due to radar signals strongly reflecting off flat surfaces like roads and buildings. The small areas of yellow may be produced by a range of factors, including land cover, soil moisture, and surface geometry.
With radar images like these, scientists can look for changes in backscatter over time to tell where trees and plants have been removed, regrown, or destroyed, and to estimate how much carbon is stored in forests. Monitoring the boundaries of water and wetlands provides insight into flood risks or shifts in river channels.
Yellow-green in the imagery indicates the forests and wetlands covering the region. Those are interrupted by the dark blue peaks of Mount Rainier and Mount Saint Helens, two of the best-known natural landmarks in the Pacific Northwest. Dark blue is representative of relatively smooth surfaces, including both water and exposed mountaintops. Near the foot of each mountain are patches of purple squares cut into the lighter-green vegetation. Their precise right angles indicate that they’re human-made, and most likely the effect of forests being thinned or vegetation growing back after having been thinned in the past.
“A single radar image is a snapshot of the surface conditions,” Downs said. “But scientists typically rely on a time series of images to understand what’s happening. One of NISAR’s strengths is it observes the same areas twice every 12 days, producing a sequence of radar measurements that tells a full story.”
A joint mission developed by NASA and ISRO, NISAR was launched in July 2025 from Satish Dhawan Space Centre on India’s southeastern coast. Managed by Caltech, JPL leads the U.S. component of the project and provided the satellite’s L-band SAR, with a wavelength of 9 inches (24 centimeters), and antenna reflector. The spacecraft bus, the S-band SAR, which operates at a wavelength of 4 inches (10 centimeters), as well as the launch vehicle and launch services were provided by ISRO.
The NISAR satellite is the first to carry two SAR instruments at different wavelengths and monitors Earth’s land and ice surfaces twice every 12 days, collecting data using the spacecraft’s giant drum-shaped reflector, the largest radar antenna reflector NASA has ever sent into space.
To learn more about NISAR, visit:
https://science.nasa.gov/mission/nisar/
Media Contacts
Andrew Good / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433 / 626-379-6874
andrew.c.good@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
2026-019
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