La Niña

La Niña is a coupled ocean-atmosphere phenomenon which is part of the ENSO (El Niño/Southern Oscillation) climate pattern. La Niña is the counterpart of El Niño. It is characterized by lower temperatures of sea surface waters of the equatorial Eastern Central Pacific.

Thus, during La Niña, the Pacific sea-surface height is higher (warmer) than normal West of the basin, while it is lower East stretching to the central Pacific Ocean.

La Niña changes global weather patterns with opposite effects to those resulting from El Niño. La Niña generally causes dry episodes along the coasts of North and South America, and drought conditions in the western Pacific.
As an example, the La Niña episode in 2010 caused one of the worst flooding faced by Australia over the last 50 years. A new La Niña episode is ongoing and is expected to continue for a few months.

Thanks to its capacity to measure ocean characteristics (e.g. temperature, currents, sea level, etc.), the GMES Marine Environment Monitoring service developed by MyOcean contributes to the monitoring of events such as El Niño or La Niña and can therefore help mitigating their negative impacts.

The animation below illustrates the El Niña phenomenon by showing variations of Pacific sea surface height during the period April - September 2010: the sea surface is higher (warmer) than normal (yellow and red) in the West; and lower (cooler) than normal (blue and purple) in the East.