Impact of El Niño and La Niña on Rainfall

How El Niño and La Niña affect Rainfall

El Niño 1997

La Niña, 1988

El Niño and its counterpart La Niña alter weather patterns across the world. These images show the strongest El Niño and La Niña events of the past twenty years and their impact on rainfall over North and South America.

The top image pair shows the El Niño event of 1997, and the direct correlation between warm surface waters and rainfall. The 1997 El Niño was unusually strong and brought heavy rain to northwest South America and the southern United States. Cooler ocean temperatures caused drought in Australia and Indonesia, as shown in the 1997 rainfall anomaly image.

The lower image pair shows La Niña in 1988 . La Niña occurs when the eastern Pacific off the coast of South America cools. The unusually cold ocean cools the atmosphere above it. The cool, dense air means less  rain falls over the cold waters in the eastern equatorial Pacific. Image reveals that the drought reached Peru and Ecuador in northwest South America. Globally, La Niña causes unusually heavy rain in India, Southeast Asia, Australia, and southeastern Africa.

NASA Earth Observatory images by Rob Simmon and Jesse Allen, based on data from the National Oceanic and Atmospheric Administration’s Advanced Very High Resolution Radiometer and the Global Precipitation Climatology Project at NASA Goddard Space Flight Center. Caption by Holli Riebeek. [Edited for brevity by FEWW]

Related Links:

• El Niño