On July 30, 2025, a massive 8.8-magnitude earthquake struck off Russia’s Kamchatka Peninsula. A little over an hour later, the Surface Water and Ocean Topography (SWOT) satellite captured the passing tsunami in unprecedented detail. It recorded a wave height of more than 45 centimeters (1.5 feet), providing a real-world test for forecast models as the water surged across the Pacific Ocean.
With that event, coastal communities were able to act, adding protections and bracing for tidal changes with a keener understanding of the wave’s timing and possible impacts. SWOT — a joint venture between NASA and France’s Centre National d’Etudes Spatiales (CNES), with support from the Canadian and United Kingdom space agencies — is designed to offer scientists a detailed, first look at the makeup and extent of such ocean events, providing insights that can dramatically improve warnings for communities and international shipping.
“The power of SWOT’s broad, paintbrush-like strokes over the ocean is in providing crucial real-world validation, unlocking new physics, and marking a leap towards more accurate early warnings and safer futures,” said Nadya Vinogradova Shiffer, NASA Earth lead and SWOT program scientist at NASA headquarters in Washington.
SWOT’s measurements revealed not just the height of the wave but also its shape and direction. These data points were compared with U.S. National Oceanic and Atmospheric Administration (NOAA) tsunami forecast models and the results matched, confirming the model’s accuracy. “A 1.5-foot-tall wave might not seem like much, but tsunamis are waves that extend from the seafloor to the ocean’s surface,” said Ben Hamlington, an oceanographer at NASA’s Jet Propulsion Laboratory in Southern California. “What might only be a foot or two in the open ocean can become a 30-foot wave in shallower water at the coast.”
The importance of SWOT’s data extends beyond any single event. NOAA’s Center for Tsunami Research is using its observations to refine its forecast models and reinforce the alerts sent to vulnerable coastal areas. Chief scientist Vasily Titov called the results exciting, noting that SWOT data could revolutionize tsunami forecasts — a capability sought since the catastrophic 2004 Sumatra event that killed some 230,000 people, he told NASA.
Josh Willis, a JPL oceanographer, emphasized the value of satellite-based observations: “The satellite observations help researchers to better reverse engineer the cause of a tsunami, and in this case, they also showed us that NOAA’s tsunami forecast was right on the money.”
SWOT does more than track and monitor storms. During calmer periods it explores rivers, lakes and seas to determine how much water is present; where it’s moving; and how the bodies are changing in size, shape and height in relation to wind, temperature and other external forces. The results offer insights to potentially affect freshwater storage, fisheries management, shipping, agriculture and offshore operations.
“This means that we will know the changes in the volume of water, the storage, how much water we have on continents in those water bodies. But we also know how water is flowing through them,” Cédric David, a JPL hydrologist, told a NASA interviewer ahead of SWOT’s December 2022 launch.
SWOT’s mission
SWOT’s journey began in 2007 when it was included in the National Research Council’s Decadal Survey of Earth science missions, according to NASA. Years of international teamwork followed, resulting in a December 16, 2022, launch aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California.
SWOT’s mission was to make the first global survey of Earth’s surface water and observe the intricate details of the ocean’s surface topography. The satellite’s payload included advanced instruments, such as the Ka-band radar interferometer, GPS receiver, microwave radiometer and technology contributions from all participating agencies. These tools allowed SWOT to track all of Earth’s waters with unmatched precision, studying lakes, rivers, reservoirs and oceans at least once every 21 days to improve ocean circulation models, provide weather and climate predictions, and aid in freshwater management around the world, a JPL mission overview said. “In the ocean, we’ll be continuing 30 years of observations of sea levels, but doing that in such a much finer way that we’ll be able to better understand ocean currents. That’s really important for things like navigation, for example,” David said.
Predecessors
SWOT was preceded by other ocean-monitoring satellites, beginning with Seasat, which launched in June 1978. Seasat operated for 105 days before a power system failure ended the mission. Despite its short lifespan, Seasat collected more information about ocean physics than had been acquired in the previous 100 years of shipboard research, JPL said. It provided valuable data on sea-surface winds and temperatures, wave heights, atmospheric conditions and ocean topography. It also established satellite oceanography and proved the viability of several radar sensors, including an imaging radar to study the planet.
After Seasat, precise sea surface measurements were conducted by the TOPEX/Poseidon mission and Jason satellite missions. Sent into orbit in 1992, TOPEX/Poseidon was the result of a joint venture between CNES and NASA to measure ocean surface topography to an accuracy of 4.2 centimeters. This would enable scientists to forecast the 1997-1998 El Niño and provide improved understanding of ocean circulation and its effect on weather patterns worldwide. TOPEX stands for “Topography Experiment.” While a three-year prime mission was planned, TOPEX/Poseidon delivered 13-plus years of data from orbit, according to NASA.
The Jason satellite program — Jason-1, Jason-2 and Jason-3 — followed in the 2000s. Named after the Greek mythological hero who led the Argonauts on a quest to find the Golden Fleece, the program’s mission was to monitor global ocean circulation, weather changes and sea-level rise by measuring sea surface height using radar altimeters on low Earth orbiting satellites. The program arose out of an international effort involving NASA, NOAA, CNES and the European Organisation for the Exploitation of Meteorological Satellites. The Jason-3 ocean altimeter satellite is still active, collecting data on ocean circulation, sea-level rise and wave height.
Looking ahead
Amid growing challenges posed by weather, rising sea levels and water scarcity in some regions, SWOT’s ability to observe and understand Earth’s water cycles — including tsunamis in the Pacific Ocean and rivers on every continent — is increasingly critical to scientists to help communities adjust to future weather changes and avoid catastrophes.
SWOT differed from earlier altimeter satellites in that it provided the first truly global observations of changing water levels, stream slopes and the flooding of rivers, lakes and floodplains. It also observes ocean circulation at an unprecedented scale of 15 to 25 kilometers. The JPL said SWOT’s mission is due to wrap up at the end of 2025, although, like its predecessors, it might send data for months or years afterward.
SWOT’s impact on weather research and water resource management will likely endure for years, specifically to help scientists:
- Understand how oceans absorb heat and carbon, which affects global temperatures.
- Study coastal sea-level changes and their impact on events like storm surges and flooding.
- Monitor the health and volume of freshwater bodies, aiding in water management and resource allocation.