Earth (NASA/NOAA) – After three consecutive years of La Niña, spring 2023 saw the return of El Niño—a natural climate phenomenon characterized by the presence of warmer than normal sea surface temperatures (and higher sea levels) in the central and eastern tropical Pacific Ocean.
El Niño is associated with the weakening of easterly trade winds and the movement of warm water from the western Pacific toward the western coast of the Americas. The phenomenon can have widespread effects, often bringing cooler, wetter conditions to the U.S. Southwest and drought to countries in the western Pacific, such as Indonesia and Australia.
Satellite- and ocean-based measurements of sea surface temperature are one way to detect the arrival of El Niño. Its signature also shows up in satellite measurements of sea surface height, which rises as ocean temperatures warm up. That’s because warmer water expands to fill more volume, while cooler water contracts.
The map depicts sea surface height anomalies across the central and eastern Pacific Ocean as observed from June 1–10, 2023. Shades of blue indicate sea levels that were lower than average; normal sea level conditions appear white; and reds indicate areas where the ocean stood higher than normal.
Data for the map were acquired by the Sentinel-6 Michael Freilich and Sentinel-3B satellites and processed by scientists at NASA’s Jet Propulsion Laboratory (JPL). Note that signals related to seasonal cycles and long-term trends have been removed to highlight sea level anomalies associated with El Niño and other short-term natural phenomena.
