La Niña (Spanish: the girl) describes a climate phenomenon in the tropical Pacific, which describes the weather primarily in the southern Pacific region, but also has global effects. The more well-known brother of La Niña is El Niño (Spanish: the boy).
El Niño describes the phases of pronounc warming of the equatorial Pacific, starting from the South American coast towards the west. This increase in seawater temperature can be 3 to 5 degrees in strong events, and over 5 degrees in very strong events. Strong or very strong El Niño events repeat themselves approximately every 10 years. In between there are more frequent weak “El Niños”. However, when the sea surface temperature is below average, it is referr to as La Niña.
This phenomenon of sea temperature deviations is associat with atmospheric circulation changes. The entire phenomenon is known as El Niño Southern Oscillation (ENSO). The so-call multivariate ENSO index MEI (multivariate El Niño Southern Oscillation Index) is often us today as a measure of the strength of El Niño and La Niña. The MEI is calculat from the surface pressure, the east-west and north-south components of the surface wind, the sea surface temperature, the air temperature at sea level and the degree of cloud cover in the equatorial Pacific.
The multivariate ENSO index MEI.v2 over the last decades
The El Niño phases are shown in r, the La Niña phases in blue. Source: https://psl.noaa.gov/enso/mei/
The multivariate ENSO index MEI.v2 over the last decades. The El Niño phases are shown in r, the La Niña phases in blue. Source: https://psl.noaa.gov/enso/mei/
Current situation and forecasts for the next few months
In September 2024, neither El Niño nor La Niña conditions prevail, or sri lanka mobile database in more scientific terms: the ENSO index was neutral, and sea surface temperatures in the central and eastern equatorial Pacific were almost average. However, the long-term models now show an increas probability (around 60%) that La Niña will continue until the end of the year, and probably until March 2025. The most likely event seems to be a weak La Niña event. If this does not occur, balanc ENSO conditions are likely to prevail. It is unlikely that El Niño will occur in the coming months. This information is bas on data from the
NOAA Climate Priction Center
.
What is the impact on other regions of the world?
The phenomenon describ above occurs in the tropical Pacific. There, colder or warmer sea temperatures change temperature, wind and precipitation conditions. But such changes in the atmospheric circulation how to choose the best free web host? pattern also have an impact on distant parts of the world.
Influence of La Niña on temperatures in different parts of the world. Blue means colder than normal, yellow means warmer than normal. Source: https://www.metoffice.gov.uk/
Influence of La Niña on temperatures in different parts of agb directory the world. Blue means colder than normal, yellow means warmer than normal. Source: https://www.metoffice.gov.uk/
Influence of La Niña on precipitation in different parts of the world. Blue means more precipitation than normal, yellow less than normal. Source: https://www.metoffice.gov.uk/
Influence of La Niña on precipitation in different parts of the world. Blue means more precipitation than normal, yellow less than normal. Source: https://www.metoffice.gov.uk/
There are still uncertainties regarding the long-range impact on Europe. The middle latitudes are naturally characteriz by high variability, and the so-call North Atlantic Oscillation has a greater influence here. The connection between the conditions in the tropics and the weather in Europe is being investigat using climate models.