Uploaded July 2026 | Updated September 2026, 3 weeks ago
As the Pacific Ocean moves into an El Niño phase, scientists are monitoring changes in sea-surface temperature, but also sea-surface salinity – which is another key indicator of this phenomenon. Measurements from satellites such as the European Space Agency's SMOS mission are revealing how freshwater and salt patterns shift across the Pacific as this year’s El Niño develops – offering a potential new pathway for early detection.
Drawing on data from ESA’s SMOS and NASA’s SMAP missions and other data sources, the animation illustrates the movement of the freshwater pool during the 2023 El Niño and La Niña events, and the current emerging El Niño.
Here, the eastern edge of the western Pacific freshwater pool shifts eastwards, together with the associated belt of deep atmospheric convection and heavy rainfall. One of the most striking features is the eastward displacement of the saltier waters immediately to the east of the freshwater pool, while salinity within much of the pool itself remains relatively low. This evolution reflects the combined influence of changing rainfall patterns and ocean surface currents as the trade winds weaken during El Niño.
Read full story: https://www.esa.int/Applications/Observing_the_Earth/FutureEO/SMOS/SMOS_salinity_could_offer_early_indicator_of_El_Nino
Credits: F. Bonjean/LOCEAN, adapted by ESA (data sources: ESA, NASA)
Access the video on the ESA video library: https://www.esa.int/ESA_Multimedia/Videos/2026/07/Shifting_freshwater_pool_of_the_El_Nino_Southern_Oscillation
Our main YouTube channel: youtube.com/@EuropeanSpaceAgency
We are Europe's gateway to space. Our mission is to shape the development of Europe's space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world. Check out https://www.esa.int/ to get up to speed on everything space related.
Copyright information about our videos is available here: https://www.esa.int/ESA_Multimedia/Terms_and_Conditions
As the Pacific Ocean moves into an El Niño phase, scientists are monitoring changes in sea-surface temperature, but also sea-surface salinity – which is another key indicator of this phenomenon. Measurements from satellites such as the European Space Agency's SMOS mission are revealing how freshwater and salt patterns shift across the Pacific as this year’s El Niño develops – offering a potential new pathway for early detection.
Drawing on data from ESA’s SMOS and NASA’s SMAP missions and other data sources, the animation illustrates the movement of the freshwater pool during the 2023 El Niño and La Niña events, and the current emerging El Niño.
Here, the eastern edge of the western Pacific freshwater pool shifts eastwards, together with the associated belt of deep atmospheric convection and heavy rainfall. One of the most striking features is the eastward displacement of the saltier waters immediately to the east of the freshwater pool, while salinity within much of the pool itself remains relatively low. This evolution reflects the combined influence of changing rainfall patterns and ocean surface currents as the trade winds weaken during El Niño.
Read full story: https://www.esa.int/Applications/Observing_the_Earth/FutureEO/SMOS/SMOS_salinity_could_offer_early_indicator_of_El_Nino
Credits: F. Bonjean/LOCEAN, adapted by ESA (data sources: ESA, NASA)
Access the video on the ESA video library: https://www.esa.int/ESA_Multimedia/Videos/2026/07/Shifting_freshwater_pool_of_the_El_Nino_Southern_Oscillation
Our main YouTube channel: youtube.com/@EuropeanSpaceAgency
We are Europe's gateway to space. Our mission is to shape the development of Europe's space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world. Check out https://www.esa.int/ to get up to speed on everything space related.
Copyright information about our videos is available here: https://www.esa.int/ESA_Multimedia/Terms_and_Conditions
