International Sea Level Satellite Observes El Niño Precursor
Sea level height data from the international Sentinel-6 Michael Freilich satellite collected from March to May 2026 show higher, warmer water moving from the western Pacific Ocean to just off the coast of Colombia, Ecuador, and Peru. This phenomenon is known as a warm Kelvin wave, signified in this animation of the data by yellow, orange, red, and white. The emergence of Kelvin waves in the early part the year is a signal that an El Niño event is likely to follow.
In early 2026, measurements from Sentinel-6 Michael Freilich showed a small Kelvin wave forming around Micronesia in late January and dissipating by mid-February. The wave shown in the animation emerged in early March, then moved east over time. By mid-May, the seas around Peru were more than 5.9 inches (15 centimeters) higher than long-term averages. Because water expands as it warms, a rise in elevation of an area of the ocean indicates increasing temperature.
The additional heat at the sea surface can change the circulation patterns of energy, water, and air in the atmosphere, which can affect weather. El Niños can cause heavy precipitation in some regions and deficits in others, influencing daily life and commerce around the world.
Sentinel-6 Michael Freilich, named after former NASA Earth Science Division Director Michael Freilich, is one of two satellites that compose the Copernicus Sentinel-6/Jason-CS (Continuity of Service) mission.
Sentinel-6/Jason-CS was jointly developed by ESA, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), NASA, and NOAA, with funding support from the European Commission and technical support on performance from the French space agency CNES (Centre National d’Études Spatiales). Spacecraft monitoring and control, as well as the processing of all the altimeter science data, is carried out by EUMETSAT on behalf of the European Union’s Copernicus programme, with the support of all partner agencies.
A division of Caltech in Pasadena, NASA’s Jet Propulsion Laboratory contributed three science instruments for each Sentinel-6 satellite: the Advanced Microwave Radiometer, the Global Navigation Satellite System - Radio Occultation, and the Laser Retroreflector Array. NASA also contributed launch services, ground systems supporting operation of the NASA science instruments, the science data processors for two of these instruments, and support for the U.S. members of the international Ocean Surface Topography Science Team.
To learn more about Sentinel-6 Michael Freilich, visit: