Why do extreme weather often appear recently?

Oh, you're right, it's an El Nino phenomenon. It was reported last year and early this year. Now the rising temperature is beyond the control of human beings. It's terrible. Not only in China, but also in Bangladesh! ! !

This is an introduction. For details, please visit /sshtmj!

English name: El Nino phenomenon

Mbth: elninophenomenon

Content:

El Nino phenomenon, also known as El Nino current, is a large-scale interaction between the ocean and the atmosphere in the equatorial Pacific.

Climate phenomenon caused by loss of balance after action. Under normal circumstances, the monsoon air flow in the tropical Pacific moves from America to Asia, keeping the surface of the Pacific Ocean warm and bringing tropical rainfall around Indonesia. However, this pattern is disturbed every 2-7 years, and the wind direction and ocean current are reversed. The heat flow in the surface of the Pacific Ocean turns eastward to America, and then takes away tropical rainfall, resulting in the so-called "El Ni? o phenomenon".

The word "El Nino" comes from Spanish, which means "El Nino". /kloc-at the beginning of the 0/9th century, in South America.

In Spanish-speaking countries such as Ecuador and Peru, fishermen find that every few years, from 10 to.

In March of the following year, there will be a warm current moving southward along the coast, which will obviously increase the surface seawater temperature. The Peruvian cold current originally prevailed on the east coast of the Pacific Ocean in South America. Fish that move with the cold current make Peru's fishing ground one of the three largest fishing grounds in the world. But when this warm current appears, a large number of fish who like cold water will die, leading to the extinction of fishermen. Because this phenomenon is often the most serious around Christmas, fishermen who suffer from natural disasters and are helpless are called the son of God-El Nino. Later, in science, the term was used to indicate the abnormal warming of sea surface temperature in the eastern Pacific Ocean thousands of kilometers near Peru and Ecuador. When this happens, the sea water temperature in a wide range can be 3-6 degrees Celsius higher than normal. The rising water temperature in the vast waters of the Pacific Ocean has changed the traditional equatorial currents and southeast trade winds, resulting in global climate anomalies.

The basic feature of El Nino phenomenon is that the sea surface temperature along the Pacific coast rises abnormally, the sea water level rises, and a warm current flows southward. It turns cold water in the East Pacific into warm water, causing tsunamis and storms, causing drought in some areas and excessive rainfall in others.

The whole process of El Nino is divided into occurrence period, development period, maintenance period and attenuation period, which generally lasts for about one year, and the change of atmosphere lags behind the change of seawater temperature.

Today, with the highly developed meteorological science, people have understood that the central Pacific Ocean is the main power source of summer climate change in the northern hemisphere. Usually, there is a northward Peruvian cold current in the Pacific Ocean on the west side of the South American continent, and part of it turns into an equatorial flow and moves westward. At this time, the monsoon blowing westward along the sea near the equator makes the warm current accumulate to the west side of the Pacific Ocean, while the low-level cold sea water rises to the east side, which makes the sea temperature in the western Pacific Ocean south of the Philippines and north of New Guinea rise. This part of the sea area is called "equatorial warm pool", and the seawater temperature in the east of the same latitude is relatively low. There is also a temperature difference in the atmosphere over the two sea areas. The temperature in the east is low and the air pressure is high, and the cold air sinks and flows westward. The temperature in the west is high and the air pressure is low. After the hot air rises, it turns to the east. In this way, an atmospheric circulation (Walker circulation) is formed in the middle of the Pacific Ocean, and the southeast trade wind is formed near the sea level. But sometimes, this pressure difference will be lower than the multi-year average, and sometimes it will increase. This phenomenon of atmospheric change is called "Southern Oscillation". In 1960s, meteorologists found that El Nino was closely related to the Southern Oscillation. When the pressure difference decreased, El Nino appeared. After El Nino, due to the warming of warm current, the monsoon flowing from east to west in the Pacific Ocean was greatly weakened, which significantly changed the atmospheric circulation and greatly affected the climate of countries along the Pacific Ocean. The originally wet area was dry, and there was a flood in the dry area. When this pressure difference increases, the seawater temperature will drop abnormally, which is called "La Nina phenomenon".

After the 1960s, with the progress of observation means and the development of science, people discovered Earle.

Nino phenomenon not only appears in the coastal areas of South America and other countries, but also covers all the sea areas along the equator of the eastern Pacific Ocean and countries around the Pacific Ocean. In some years, even the Indian Ocean coast will be affected by the climate anomaly caused by El Ni? o, and a series of natural disasters will occur. Generally speaking, it makes the climate in the southern hemisphere hotter and drier, and the climate in the northern hemisphere colder and wetter.

In recent years, scientists have put forward some new explanations for the El Ni? o phenomenon, that is, El Ni? o may be related to submarine earthquakes, changes in seawater salinity and changes in atmospheric circulation.

El Nino occurs periodically, about once every 2-7 years. During the 20 years from 65438 to 0997, El Nino occurred five times in 76-77, 82-83, 86-87, 9 1-93 and 94-95 respectively. The El Ni? o phenomenon during 1982- 1983 was the most serious since this century, which caused about 1500 deaths and 8 billion US dollars in property losses all over the world. After entering the 1990s, with global warming, El Nino phenomenon appeared more and more frequently.

Due to the development of science and technology and the attention of countries all over the world, scientists have deepened their understanding of this climate anomaly by adopting a series of scientific research activities such as forecasting model, ocean observation and satellite reconnaissance, and air-sea coupling. Firstly, it is recognized that the physical process of El Ni? o phenomenon is the result of the interaction between the ocean and the atmosphere, that is, the change of ocean temperature is related to the atmosphere. Therefore, after 1980s, scientists called El Nino "Anceaux". Secondly, tropical ocean warming occurs not only in the Chilean waters of South America, but also in the eastern and western Pacific. No matter where it happens, it will quickly lead to obvious global climate anomalies. This is the strongest signal of climate change, which will lead to serious natural disasters, such as droughts and floods in many parts of the world.