NASA's scientists produced a new animation showing the 2015 El Niño event unfolding the Pacific Ocean. Observed changes in the sea surface temperature (SST) vary greatly from those typical for the 1997/98 phenomenon; they are stronger and deeper. The La Niña forecast still remains fairly uncertain.
During El Niño, variations of the water temperature occur not only at the surface of equatorial Pacific but also below the surface. This season, sea surface temperatures have produced different patterns when compared with 1997/98 event. During the El Niño maximum in November 2015, colder than average temperatures were reported in the Western Pacific while warmer than average conditions took place in the Eastern Pacific. Also, the changes in temperature were stronger and extended deeper than during 1997.
Visualization showing sea surface temperature (SST) anomaly data from January 1, 2015, through February 14, 2016. Video credit: NASA
Visualization showing sea surface temperature (SST) anomaly data from January 1, 1997, through February 14, 1998. Video credit: NASA
The 1997 event started with colder than average SSTs while the current phenomenon started with warmer than average temperatures in the Pacific, Atlantic and Indian Oceans.
"The '97 El Niño was much stronger in the Eastern Pacific, with much warmer water up to the coast of South America," said Robin Kovach, a research scientist with the Global Modeling and Assimilation Office (GMAO). Unlike that, the Central Pacific and a region west of the International Date Line have seen the warmest waters in 2015.
NASA's computer models utilized the input data from ocean buoys, atmospheric models, satellite data and numerous other sources to simulate the behavior of the ocean temperatures over the coming months. The GMAO seasonal forecast model suggests the current phenomena will retain its different characteristics until the end. Models run in February 2016 predict the SSTs will return to normal by June.
Visualization showing sea surface temperature (SST) anomaly data and subsurface temperature anomaly data from January 1, 2015, through February 14, 2016. Video credit: NASA
Visualization showing sea surface temperature (SST) anomaly data and subsurface temperature anomaly data from January 1, 1997, through February 14, 1998. Video credit: NASA
The February 5 run of the model doesn't predict the colder-than-average temperatures, necessary to produce a large La Niña. As of February 14, the computer simulation indicates colder-than-average conditions off the South American coast, extending from Ecuador to Panama.
In the past, very strong El Niño events typically transition to neutral conditions and then a La Niña event. This current El Niño has been different so it will be interesting to see what happens in the next forecast and the coming months.
Featured image: El Niño phenomenon, November 2015. Image credit: NASA