Early sea level signals that El Niño is arriving
The latest sea level data from the Sentinel-6 Michael Freilich satellite indicate. EARLY SIGNS in the equatorial Pacific Ocean of a developing El Niño, a periodic climatic phenomenon that can affect global weather patterns.
The data show Kelvin waves-a potential precursor to these conditions-which are approximately de 5 to 10 centimeters high at the ocean surface. and hundreds of kilometers wide, moving west to east along the equator toward the west coast of South America.
When they form at the equator, Kelvin waves bring warm water, which is associated with higher sea levels, from the western Pacific to the eastern Pacific. A series of Kelvin waves beginning in the spring is a known precursor to El Niño. This phenomenon is characterized by higher sea levels and warmer than average ocean temperatures along the western coasts of the Americas.
Water expands as it warms, so sea levels tend to be higher in places with warmer water. El Niño is also associated with a weakening of trade winds. The condition may bring cooler and wetter conditions to the southwestern U.S. and drought to western Pacific countries, such as Indonesia and Australia.
“Ocean waves dump heat around the planet, bringing warmth and moisture to our shores and changing our climate.”
The latest data from the Sentinel-6 Michael Freilich satellite cover the period between early March and late April 2023. By April 24, Kelvin waves had built up warmer water and higher sea levels (shown in red and white) off the coasts of Peru, Ecuador and Colombia. Satellites such as Sentinel-6 Michael Freilich can detect Kelvin waves with a radar altimeter, which uses microwave signals to measure the height of the ocean surface. When an altimeter passes over areas that are warmer than others, the data will show higher sea levels.
Record global warming
“We’ll be watching this El Niño like a hawk.”, Josh Willis, Sentinel-6 Michael Freilich project scientist at NASA’s Jet Propulsion Laboratory in Southern California, said in a statement. “If it’s big, the globe will see record warming, but in the southwestern U.S. we could be looking at another wet winter, immediately following the soaking we had last winter.”
Both the U.S. National Oceanic and Atmospheric Administration (NOAA) and the World Meteorological Organization have recently reported that there is a greater chance that El Niño will develop in late summer. Continued monitoring of ocean conditions in the Pacific by instruments and satellites such as Sentinel-6 Michael Freilich should help clarify in the coming months how strong it could become.
“When we measure sea level from space using satellite altimeters, we know not only the shape and height of the water., but also their motion, such as Kelvin and other waves,” said Nadya Vinogradova Shiffer, NASA program scientist and Sentinel-6 manager Michael Freilich in Washington. “Ocean waves dump heat around the planet, bringing warmth and moisture to our shores and changing our climate.”