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How 2 US, European Satellites Are Studying Hurricanes During El Niño

✇NASA Breaking News
By: Stephen Carney

5 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Category 5 Hurricane Melissa, one of the most powerful storms to strike the Caribbean in recent history, is pictured about 50 miles south of Jamaica in this photograph from the International Space Station as it orbited 262 miles above the Yucatan Peninsula.
Hurricane Melissa is seen 50 miles south of Jamaica in this photograph taken from the International Space Station on Oct. 28, 2025.
NASA

Last November, NASA and its European partners launched the Sentinel-6B satellite to improve hurricane forecasts, help protect infrastructure, and benefit commercial industries, including shipping. The satellite now is flying 30 seconds behind its predecessor, Sentinel-6 Michael Freilich. Both satellites are providing precise sea level height measurements during what oceanographers expect to be a historic El Niño, a naturally occurring oceanic phenomenon in which warmer-than-usual Pacific waters shift global weather patterns.

The two satellites make up the Copernicus Sentinel-6/Jason-CS (Continuity of Service) mission, the latest in a series of ocean-observing radar altimetry missions that have been monitoring Earth’s changing seas continuously since the early 1990s.

The data each satellite is collecting will not only allow scientists to better understand this year’s El Niño but will also help them create more accurate hurricane predictions.

“This El Niño was a late-bloomer,” said Josh Willis, Sentinel-6B’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “It didn’t kick off until the middle of the year and is just now reaching a strength similar to what we’ve seen in the satellite record during significant El Niños in 1997 and 2015. We expect it to be big, and it’s already having big impacts.”

El Niños generally scramble weather patterns tied to rainfall and storms, including hurricanes. They also redistribute heat in the ocean, which affects sea level. Normally, Earth’s warmest ocean waters sit along the equator in the western Pacific. During El Niño, weakened winds, which usually blow westward along the equator, result in heat spreading east toward South America. The change in ocean heat shifts hurricane activity from the Atlantic to the Pacific Ocean.

Predicting hurricane strength

On July 15, Sentinel-6B began delivering low-latency data to scientists that could be used for weather predictions. That data will take some time to work its way into the research models on which meteorologists and climate scientists rely, but when it does, those improved models could save lives.

Data from Sentinel-6 satellite missions feeds into hurricane tracking algorithms used by federal and state agencies. Those predictions can activate disaster response efforts, mobilizing resources ranging from sandbag placement to National Guard activation. They also can lead to evacuation orders that require quick but well-informed decisions about logistics at a local level. More severe events may require engaging larger organizations, such as the Federal Emergency Management Agency.

A tropical storm can take a week or more to become a hurricane and make its way to a coastline, but a hurricane can rapidly intensify in the 48 hours prior to landfall, leaving planners little time to prepare.

“Hurricanes have been known to speed up quickly at the last moment, so the window in which to decide what to do is short,” said Deirdre Byrne, an oceanographer and altimetry expert with the National Oceanic and Atmospheric Administration (NOAA). “The goal is to forecast how much and how rapidly intensification will happen so that officials can make the right calls.”

Byrne oversees one of the country’s most crucial hurricane forecasting algorithms, NOAA’s Satellite Ocean Heat Content Suite, which has been operating since 2012.

Each Sentinel-6 satellite measures ocean height, as well as the size of waves and marine wind speed, using a radar altimeter, which bounces thousands of radar pulses a second off the crests and troughs of waves. Ocean height varies from place to place and provides insight into the ocean’s heat content, since warm water expands. That, in turn, helps forecast how fast hurricanes will grow.

The satellites each carry a second instrument, called the Global Navigation Satellite System – Radio Occultation (GNSS-RO), which measures atmospheric properties, such as humidity, pressure, and temperature.

Among the measurements Sentinel-6 is gathering, Byrne is most anticipating the ocean height data, which she plans to begin incorporating into the current Satellite Ocean Heat Content Suite algorithm by the end of the year.

“In terms of data quality, the Sentinel-6 missions are unparalleled,” Byrne said.

Together, the missions are also extending a precise dataset deep into its fourth decade. This record of sea level observations traces back to the TOPEX/Poseidon mission, which launched in 1992, and continues through to the present day with Sentinel-6 Michael Freilich. Sentinel-6B will take over for its predecessor as the reference satellite for global sea level measurements later this year.

“The key is consistency, measuring the same way, every time,” said Severine Fournier, Sentinel-6B deputy project scientist, JPL. “That’s what lets us predict hurricanes, and, in turn, protect coastal communities and infrastructure.”

More about Sentinel-6B

Sentinel-6 Michael Freilich, named after a former director of NASA’s Earth Science Division, is one of two satellites that compose the Copernicus Sentinel-6/Jason-CS mission.

Sentinel-6/Jason-CS, a part of the European Union’s Earth observation program called Copernicus, was jointly developed by ESA (European Space Agency), EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites), 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.

NASA JPL, a division of Caltech in Pasadena, contributed three science instruments for each Sentinel-6 satellite: the Advanced Microwave Radiometer, the GNSS-RO, and the Laser Retroreflector Array. NASA also contributed launch services, ground systems supporting operation of the agency’s science instruments, the science data processors for two of these instruments, and support for the United States members of the international Ocean Surface Topography Science Team.

For more about Sentinel-6B, visit:

https://science.nasa.gov/mission/sentinel-6B

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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

2026-060

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Europe’s Scorching Summer

✇NASA Breaking News
Output from NASA’s GEOS (Goddard Earth Observing System) global model shows daily maximum surface air temperature across Western Europe from May 1 to August 19, 2026. The darkest red areas indicate temperatures that met or exceeded 40°C (104°F).
NASA Earth Observatory/Lauren Dauphin

Western Europe got its first hint of an unusual summer in May 2026, when a heat dome produced exceptional temperatures that shattered records in several countries. Remarkable as it was, that early heat wave turned out to be only the opening salvo.

By mid-August, Europeans were sweating through their fifth heat wave of the season, with the latest onslaught pushing temperatures well above 40 degrees Celsius (104 degrees Fahrenheit) across a broad area. During these bouts of extreme weather, high temperatures were often unrelenting, persisting for several days and sometimes weeks on end, and remaining overnight.

For a region accustomed to relatively mild summers, the heat upended everyday life. Hospitalizations and heat-related deaths spiked. Highways and train tracks buckled, forcing road closures and service disruptions. Large and destructive wildfires raged in areas where they were once rarely seen. The heat also worsened the severe drought that has gripped the region for months, contributing to record-low river water levels and disrupting water and power supplies, transportation routes, and agriculture.

The animation above shows the daily maximum surface air temperature across Western Europe from May 1 to August 19, 2026. It was produced by combining satellite observations with temperatures predicted by a version of NASA’s GEOS (Goddard Earth Observing System) global model, which uses mathematical equations to represent physical processes in the atmosphere. The darkest red areas indicate where temperatures met or exceeded 40°C.

The heat broke records at a furious pace, often by wide margins. According to the UK Met Office, temperatures soared as high as 35.1°C (95.2°F) in London on May 26, smashing the previous May record by 2.3°C (4.1°F). In June, Bordeaux, France, broke its maximum-temperature record on three consecutive days, hitting 42.5°C on June 24, Météo-France reported. Slovakia, meanwhile, set new national records for both daytime and nighttime highs in August. Combined June and July temperatures in Western Europe were the highest on record, according to Europe’s Copernicus climate monitoring service.

In Europe, extreme temperatures collided with several vulnerabilities, including limited access to air conditioning, high nighttime temperatures, and a lack of green space in some cities. The circumstances triggered not just discomfort but heat exhaustion and heatstroke in some cases. Preliminary reports suggest that heat may have been associated with 10,000 excess deaths, including thousands of people in the UK, France, Germany, and Belgium.

“Air conditioning is an especially critical issue in Europe in the short term,” said Anamika Shreevastava, a researcher at New York University who studied urban heat islands as a postdoc at NASA’s Jet Propulsion Laboratory. One of her goals was to produce thermal maps based on NASA data from missions like ECOSTRESS that city planners could use to make cities more resilient to heat waves.

International Energy Agency data show that 23 percent of homes in Europe have air conditioning, compared to 90 percent of homes in the United States. That difference contributes to the much higher death rates that researchers have documented in European cities during heat waves than in comparable American cities. “Longer term, cities can also plant trees, expand parks, use reflective roof paint, and transition to building materials less likely to retain heat,” Shreevastava said.

An analysis from the World Health Organization indicates that heat stress is the world’s leading cause of weather-related deaths, noting it exacerbates underlying illnesses, including cardiovascular disease, diabetes, mental health conditions, and asthma. Researchers have calculated that roughly 489,000 heat-related deaths occur each year, with 45 percent of the deaths in Asia and 36 percent in Europe.

“For older adults with physical health problems, temperatures as low as 26.7°C (80°F) can pose significant danger,” said Deborah Carr, a Boston University sociologist who specializes in the study of aging. “Nighttime heat is especially harmful for older adults whose homes lack air conditioning.”

Carr is part of a research team that used demographic data, along with temperature and climate data archived by NASA, to identify which parts of the world are at the greatest risk of current and future heat exposure. Southern Europe was among the areas facing growing heat exposure and an aging population, the researchers found.

Other research, published in Lancet Planetary Health in August 2026, underscores the importance of demographics in assessing the risks posed by heat. This study, led by Stanford researcher Qinqin Kong, mapped where increasing heat is likely to lead to intolerable conditions in the coming decades for young, middle-aged, and older adults, concluding that safe thresholds will be breached often and widely, with risks falling disproportionately on older people.

“The human body can tolerate only a limited range of ambient heat,” said Kong, a recipient of a NASA Earth and Space Science and Technology award. “Understanding where, when, and to what extent these limits are exceeded is critical.”

With intolerable levels of heat expected to affect more people across larger regions and for longer periods than previously thought, Kong and his colleagues hope that their findings will inform targeted heat action plans, emergency preparedness, and health system planning.

NASA Earth Observatory image by Lauren Dauphin, using GEOS-FP data from the Global Modeling and Assimilation Office at NASA GSFC. Story by Adam Voiland.

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