Latest news with #flowwaves
Washington Post
3 days ago
- Science
- Washington Post
Satellite measures river flow waves for the first time
Long river waves, known as flow waves, have been measured by satellite for the first time, researchers announced May 14, a breakthrough that could expand understanding of river dynamics, floods and the other hazards sometimes present when the waves form. In a study in Geophysical Research Letters, the researchers found that the long waves can be spotted and studied using data from a NASA-French space agency satellite designed to study Earth's water.
Gizmodo
22-05-2025
- Science
- Gizmodo
NASA Satellites Capture ‘River Tsunamis' Surging Hundreds of Miles Inland
Giant ocean waves engulfing tiny boats are the stuff of nightmares—but it turns out rivers also form flood waves that are nothing to sneeze at. That's according to researchers from Virginia Tech and NASA's Jet Propulsion Laboratory (JPL), who measured three large flood waves, also called flow waves, in U.S. rivers via satellite data. They claim their approach is the first of its kind, and could inform flood mitigation and warning efforts. While tides and wind drive ocean waves, intense rain or snowmelt can trigger river waves, which consist of water surges that can span hundreds of miles. River waves are crucial to the movement of nutrients and organisms, but can also be dangerous. 'Analyzing flow wave dynamics to answer questions such as, 'How high could water levels rise during a flow wave?' and 'How fast do flow waves travel?' has important implications for human safety, infrastructure design and management, and fluvial ecology,' the researchers wrote in a study published May 14 in the journal Geophysical Research Letters. The team investigated this phenomenon in data from NASA and the French space agency CNES' Surface Water and Ocean Topography (SWOT) satellite. SWOT can detect the height of almost all bodies of water on Earth's surface by shooting microwaves at the water and measuring the time it takes for them to bounce back. 'In addition to monitoring total storage of waters in lakes and rivers, we zoom in on dynamics and impacts of water movement and change,' Nadya Vinogradova Shiffer, a SWOT program scientist who did not participate in the study, said in a NASA statement. Lead author Hana Thurman, a researcher in the Department of Geosciences at Virginia Tech, found three obvious examples of river waves within the SWOT data. One occurred in Montana's Yellowstone River in April 2023, when a 9.1-foot-tall (2.8-meter-tall) crest suddenly rose and sped toward North Dakota's Missouri River. The wave's peak stretched across 6.8 miles (11 kilometers), and was likely the result of a collapsed ice jam farther up the river. 'We're learning more about the shape and speed of flow waves, and how they change along long stretches of river,' Thurman explained. A second and significantly more dramatic river wave took place in January 2024 in the Colorado River in Texas. It was 30 feet (9 m) tall, spanned 166 miles (267 km), and moved at around 3.5 feet (1.07 m) per second for over 250 miles (400 km). The third river Thurman analyzed via SWOT data formed in Georgia's Ocmulgee River two months later: 20 feet (6 m) tall, stretching across over 100 miles (165 km), and traveling at around a foot (0.33 m) per second for more than 124 miles (200 km). Rainfall likely caused both these cases. While experts can measure river waves with stream gauges, they are sparsely distributed. As such, 'satellite data is complementary because it can help fill in the gaps,' said George Allen, a Virginia Tech hydrologist and co-author of the study. The NASA statement likened stream gauges to highway toll booths—providing measurements at fixed points—while SWOT is more like a traffic helicopter taking aerial photographs as it passes by. Needless to say, such space-based observations can bolster flood detection and warning systems. 'If we see something in the data, we can say something,' Cedric David, a hydrologist at the JPL, concluded. 'For a long time, we've stood on the banks of our rivers, but we've never seen them like we are now.'
