The word El Ni?o comes from the Spanish El Ni?o, which originally means "little boy" and also refers to the Holy Child, that is, Jesus. It is used to express the westward extension on the west coast of South America (near Peru and Ecuador) , the phenomenon of abnormal warming of sea surface temperature near the date line through the equatorial Pacific Ocean.
In normal years, the southeast trade wind prevails in this area. The easterly wind stress on the equatorial surface transports surface warm water to the western Pacific, where it accumulates, causing the sea level there to rise and the seawater temperature to rise. In the East Pacific, under the influence of offshore winds, the surface seawater drifts offshore, causing continuous seawater quality divergence here, lowering the sea level, and upwelling of cold lower seawater, resulting in a decrease in sea surface temperature here. The upwelling cold seawater is rich in nutrients, causing plankton to multiply and providing sufficient food for fish. The abundance of fish provides abundant food for fish-eating birds, so there are many birds here. Due to the high sea water temperature, unstable air stratification and development of convection, the east coast of the equatorial Pacific has changed from dry and rainy to rainy, causing floods; while the west coast of the equatorial Pacific has changed from humid and rainy to humid and rainy due to the low sea water temperature and stable air stratification. Dry and less rainy.
When the southeast trade winds strengthen abnormally, the seawater in the equatorial eastern Pacific will upturn abnormally strongly and precipitation will be abnormally low; while the seawater temperature in the western equatorial Pacific will be abnormally high and precipitation will be abnormally high. This is known as a La Ni?a event. La Ni?a is the opposite of El Ni?o and refers to an abnormally low temperature in the eastern Pacific Ocean. Both phenomena are closely related to global climate and may lead to an increased chance of extreme weather.
However, every few years, the southeast trade wind weakens, the upturn of cold water in the eastern Pacific disappears, and the warm surface water flows back eastward, causing the sea level in the equatorial eastern Pacific to rise and the sea surface temperature to rise. Along the coasts of Peru and Ecuador, Transition from cold ocean currents to warm ocean currents. The inorganic salt nutrients in the lower seawater no longer flow to the sea surface, resulting in the mass death of local plankton and fish, and a large number of birds also die of starvation. forming a serious disaster. At the same time, the original dry climate changes to a rainy climate, even causing flooding. This is El Ni?o.
El Ni?o’s impact on climate is most significant in the equatorial Pacific region. During El Ni?o years, drought occurs in Indonesia, Australia, the South Asian subcontinent, and northeastern Brazil, while it is wet from the equatorial central Pacific to the west coast of South America. El Ni?o can have devastating effects, causing floods in Latin America, droughts in Australia and crop failures in India. Many observational facts also show that El Ni?o events have a certain impact on circulation changes in fairly distant areas, even in mid-to-high latitudes of the Northern Hemisphere, through teleconnections between air and sea. Research has found that when El Ni?o occurs, it will cause persistent low temperatures in the Japanese archipelago and northeastern my country in summer. In some years, precipitation in most areas of my country will tend to be less. This illustrates the integrity of the earth's surface environment from one aspect: changes in one sphere will lead to changes in other spheres, changes in one region will cause changes in other regions, and local changes will also cause changes in the hemispheric or even global environment.