How El Ni o occurs, and what causes it

El Niño"The word is of Spanish origin and means:"Holy Child"Originally used by Peruvian fishermen to describe the phenomenon of high sea temperatures along the Pacific coast around Christmas, it now refers to a phenomenon of climatic anomalies caused by rising surface sea temperatures in the eastern Pacific Ocean near the equator.

El Niño is not an isolated phenomenon, it is the product of the interaction of tropical ocean currents with the atmosphere. Every 4-7 years, the southeast trade winds in the eastern tropical Pacific weaken, causing the warm current at the south equator to weaken correspondingly, and the warm sea water flowing westward from the central and eastern Pacific Ocean decreases significantly, and even the warm sea water in the western Pacific Ocean spreads eastward in the form of equatorial countercurrent. At the same time, due to the weakening of the South Equatorial Current, the water temperature in the surface layer is 3-6 degrees Celsius higher than normal due to the weakening of the South Equatorial Warm Current, which is compensated for by the surge along the Pacific coast of South America.

In this way, in the eastern part of the tropical Pacific, due to the relative rise in the surface sea temperature, a huge amount of heat energy is generated, which activates the updrafts on the ocean surface, and heavy rains and floods occur. At the same time, the Pacific coast of South America has seen a sharp decline in plankton due to the decline in rising waters, and a large number of fish are dying due to lack of food. In contrast, in the western tropical Pacific, which used to be rainy, drought disasters occurred due to the relative drop in surface sea temperature, active downdrafts, and reduced precipitation.

El Niño, also known as El Niño Current, is a climate phenomenon caused by the eastward movement of the Walker Circulation Circle after the interaction between the ocean and the atmosphere over a large area of the Pacific Equatorial Belt. Normally, the monsoon currents in the tropical Pacific region move from the Americas to Asia, keeping the Pacific surface warm and bringing tropical rainfall around Indonesia. But this pattern is disrupted every 2 to 7 years, reversing the direction of winds and ocean currents, and the heat flow from the surface of the Pacific Ocean turns eastward towards the Americas, taking with it tropical rainfall and creating the so-called "El Niño".

The surface of the sea near the coast of Peru is unusually warm.

--- is the influence of solar activity!

El Niño is mainly caused by the weakening of the southeast trade winds and the rotation of the Earth

1. The southeast trade winds weakened.

When the southeast trade winds blowing near the equator in the southern hemisphere weaken, the cold water flooding in the Pacific region will decrease or stop, resulting in a wide range of abnormal warming of sea water temperature, and anomalies in the traditional equatorial ocean current and atmospheric circulation, resulting in abnormal precipitation in some areas along the Pacific coast, and severe drought in other places.

2. Rotation of the earth.

It is found that the occurrence of El Niño events is related to the change of the Earth's rotation speed, and the short-term change of the Earth's rotation rate is inversely correlated with the change of SST in the eastern equatorial Pacific, that is, when the Earth's rotation rate accelerates in the short term, the SST in the eastern equatorial Pacific decreases. Conversely, when the Earth's rotation rate slows down for a short time, the sea surface temperature (SST) in the eastern equatorial Pacific Ocean increases. This suggests that the slowdown in the Earth's rotation may be the main reason for the formation of El Niño.

The impact of the El Centric phenomenon on China is mainly reflected in the following points:

1. In El Niño years, the summer monsoon weakens, the location of the summer rain crack zone in China is southern, and there is little rain and drought in North China.

2. The middle and lower reaches of the Yangtze River entered the rainy season late.

3. In the autumn of El Niño year, the eastern part of China is prone to precipitation distribution similar to that of the north and the south.

4. Warm winters often occur in China.

5. In El Niño years, there are fewer tropical storms and typhoons in the northwest Pacific and the South China Sea than in previous years.

The causes of El Niño are as follows:

There are two main reasons for the formation of El Niño: First, natural factors. The equatorial trade winds, the rotation of the earth, and geothermal movements may all be related to it; The second is the human factor.

That is, due to the intensification of human activities, the emission of carbon dioxide that is too hungry and scarce is causing global warming, which may also be one of the reasons for the sharp increase in equatorial warming events.

The El Niño Warm Current is an anomalous natural phenomenon in the Pacific Ocean, which is characterized by a significant warming of the sea water in the eastern and central equatorial Pacific Oceans. On the west coast of South America and the eastern part of the South Pacific, the famous Peruvian cold snap flows from south to north, and the summer season in the southern hemisphere is from November to March.

Water temperatures in the southern hemisphere are generally warm, and the warm equatorial current, which flows westward, is strengthened. At this time, the pressure and wind bands around the world move southward, and the northeast trade winds cross the equator and are deflected to the left by the Southern Hemisphere self-deflection force (also known as the geostrophic deflection force).

The northwest monsoon not only weakens the offshore wind southeast trade winds on the west coast of Peru, weakening or even disappearing the cold water flood of Peru, but also blowing the warm equatorial current with higher water temperature southward, causing the water temperature of the cold current in Peru to rise abnormally. This quiet, irregular ocean current is known as the "El Niño Current".

Running cycle

El Niño is a cyclical natural phenomenon that occurs approximately every 7 years. Through the study of global climate, scientists believe that El Niño is not an isolated natural phenomenon, but is an aspect of global climate anomalies.

In a normal year, the Pacific coast of the west coast of Peru is controlled by a cold ocean current and has a large natural fishing ground. In the event of a climate anomaly, the cold ocean currents in the eastern Pacific Ocean are replaced by warm ocean currents.