The El Niño phenomenon is characteristic of the ocean. Climatic phenomena La Niña and El Niño, and their impact on health and society

El Niño- a natural phenomenon that is associated with global changes in climatic conditions occurring on Earth.

El Niño brings with it natural disasters, destruction and misfortune. Scientists have found that this natural phenomenon destroyed more than one civilization of the past.

Scientific circles have determined that the interaction of ocean currents and air masses is quite stable, but periodically failures occur in this system, the causes of which have not been established.

As a result, the direction of air flows and water masses changes, which in turn entails an increase in temperature in the surface layer of the ocean near the coast by up to 10 degrees. A failure necessarily brings catastrophic changes in the climate: prolonged droughts, endless rains, floods.

The frequency of El Niño is approximately 10 years.

La Niña is a phenomenon that is the direct opposite of El Niño. Feature– decrease in water temperature in the eastern Pacific Basin. This gives rise to tornadoes, drought, rains and floods.

Scientists have proven the destructive role of El Niño. American archaeologists have found that the disappearance of a particular species of mollusks and the appearance of others is an indicator of climate fluctuations.

Scientists, observing the movement of mollusks, have confirmed that when El Niño occurs, and accordingly, when the temperature of the water surface increases, some species of mollusks quickly die, while others move south. After studying mollusk shells, scientists found that in ancient times, this natural phenomenon occurred extremely rarely compared to the present time.

For scientific world The mystery of the disappearance of the Olmec civilization, which existed in the 14th-13th centuries, remains relevant. V. BC, the region of residence of which roughly corresponded to the borders of modern Mexico.

The Olmecs built monumental structures. But around the 5th century BC, the Olmecs suddenly stopped their construction, buried huge stone heads and disappeared into the swamps around their cities.

Scientists suggest that the death of the Olmec civilization is associated with the next El Niño.

Also, according to scientists, the Moche culture, which appeared around the beginning of the 2nd century BC in the northern coastal region of Peru, fell victim to the natural phenomenon of El Niño.

The Moche Indians are famous for building huge buildings from bricks, the raw materials of which were dried in the sun. This civilization is well known to scientists for its characteristic gold and ceramic products. Archaeologists have examined a pyramid near Trujillo, built during the Moche culture. Approximately a hundred skeletons were discovered buried under a thick layer of silt.

This indicates that a major flood occurred at that time.

However, scientists do not rule out the fact that the human remains found could be the result of a sacrificial ritual. The Moche Indians believed that this act would turn away from them the impending flood caused by the next El Niño.

A natural phenomenon Scientists classify El Niño/La Niña as a global catastrophe that radically changes the climate: in some parts of the planet it rains incessantly, leading to real floods, while in other parts of the Earth severe droughts occur, plunging people into famine.

So, several hundred years ago, a severe drought occurred, which caused the complete destruction of the Anasazi Indian culture that existed in southwestern Colorado. The Anasazi Indians built stone houses. But sometime around 1150 AD. the stone housing was abandoned for unknown reasons. Modern scientists conducted a study of the found remains of Indians and came to the conclusion that most of the Indians were simply eaten.

During the research, scientists were able to establish that cannibalism flourished within the territory of the Anasazi Indians.

Scientists believe that the cannibalism of that time was a consequence of the raging drought that drove other tribes from their habitats. In search of food, other tribes came to the territory of the Anasazi Indians, but they did not find anything edible here either. The source of their food was the local residents - the Anasazi Indians.

Around 1200, the drought subsided, and with it cannibalism.

German scientists from the National Center for Geosciences made a discovery - the world civilizations of Central America, the Mayans and the Tang Dynasty of China, became victims of the global El Niño. Despite the fact that these civilizations were located in different parts our planet, they died almost simultaneously.

The reason that caused the death of civilizations was the severe drought that prevailed in the 9th and 10th centuries. V. AD

The mystery of the El Niño phenomenon has not yet been completely solved. However, it is clear that it is almost impossible to defeat such a formidable opponent. A person can only rely on modern technologies and on a system of mutual assistance between countries.

El Niño

Southern Oscillation And El Niño(Spanish) El Niño- Baby, Boy) - this is a global ocean- atmospheric phenomenon. Being characteristic feature Pacific Ocean, El Niño and La Niña(Spanish) La Nina- Baby, Girl) represent temperature fluctuations of surface waters in the tropics of the eastern Pacific Ocean. The names of these phenomena, borrowed from Spanish local residents and first introduced into scientific use in 1923 by Gilbert Thomas Walker, mean “baby” and “little one,” respectively. Their influence on the climate of the southern hemisphere is difficult to overestimate. The Southern Oscillation (the atmospheric component of the phenomenon) reflects monthly or seasonal fluctuations in the difference in air pressure between the island of Tahiti and the city of Darwin in Australia.

The circulation named after Walker is a significant aspect of the Pacific phenomenon ENSO (El Niño Southern Oscillation). ENSO is many interacting parts of one global system of ocean-atmospheric climate fluctuations that occur as a sequence of oceanic and atmospheric circulations. ENSO is the world's best known source of interannual weather and climate variability (3 to 8 years). ENSO has signatures in the Pacific, Atlantic and Indian Oceans.

In the Pacific, during significant warm events, El Niño warms up and expands across much of the Pacific tropics and becomes directly correlated with SOI (Southern Oscillation Index) intensity. While ENSO events are primarily between the Pacific and Indian Oceans, ENSO events in Atlantic Ocean are 12-18 months behind the first ones. Most of the countries that experience ENSO events are developing ones, with economies that are heavily dependent on the agricultural and fishing sectors. New capabilities to predict the onset of ENSO events in three oceans could have global socioeconomic implications. Since ENSO is a global and natural part of the Earth's climate, it is important to know whether changes in intensity and frequency may result from global warming. Low frequency changes have already been detected. Interdecadal ENSO modulations may also exist.

El Niño and La Niña

El Niño and La Niña are officially defined as long-lasting marine surface temperature anomalies greater than 0.5°C crossing the central tropical Pacific Ocean. When a condition of +0.5 °C (-0.5 °C) is observed for a period of up to five months, it is classified as an El Niño (La Niña) condition. If the anomaly persists for five months or longer, it is classified as an El Niño (La Niña) episode. The latter occurs at irregular intervals of 2-7 years and usually lasts one or two years.

The first signs of El Niño are as follows:

Increase in air pressure over the Indian Ocean, Indonesia and Australia.
A drop in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean.
Trade winds in the South Pacific are weakening or heading east.
Warm air appears near Peru, causing rain in the deserts.
Warm water spreads from the western part of the Pacific Ocean to the eastern. It brings rain with it, causing it to occur in areas that are usually dry.

Warm El Niño current, consisting of plankton-poor tropical water and heated by its eastern flow in the Equatorial Current, replaces the cold, plankton-rich waters of the Humboldt Current, also known as the Peruvian Current, which contains large populations commercial fish. Most years, the warming lasts only a few weeks or months, after which weather patterns return to normal and fish catches increase. However, when El Niño conditions last for several months, more extensive ocean warming occurs and its economic impact on local fisheries for the external market can be severe.

The Volcker circulation is visible on the surface as easterly trade winds, which move water and air heated by the sun westward. It also creates oceanic upwelling off the coasts of Peru and Ecuador, bringing cold plankton-rich waters to the surface, increasing fish populations. The western equatorial Pacific Ocean is characterized by warm, humid weather and low atmospheric pressure. The accumulated moisture falls in the form of typhoons and storms. As a result, in this place the ocean is 60 cm higher than in its eastern part.

In the Pacific Ocean, La Niña is characterized by unusually cold temperatures in the eastern equatorial region compared to El Niño, which in turn is characterized by unusually warm temperatures in the same region. Atlantic activity tropical cyclones generally increases during La Niña. A La Niña condition often occurs after an El Niño, especially when the latter is very strong.

Southern Oscillation Index (SOI)

The Southern Oscillation Index is calculated from monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin.

Long-term negative values SOIs often signal El Niño episodes. These negative values typically accompany continued warming of the central and eastern tropical Pacific, decreased strength of the Pacific trade winds, and decreased rainfall in eastern and northern Australia.

Positive values SOIs are associated with strong Pacific trade winds and warming water temperatures in northern Australia, well known as a La Niña episode. The waters of the central and eastern tropical Pacific Ocean become colder during this time. Together this increases the likelihood of more rainfall than normal in eastern and northern Australia.

Extensive influence of El Niño conditions

As El Niño's warm waters fuel storms, it creates increased precipitation in the east-central and eastern Pacific Ocean.

In South America, the El Niño effect is more pronounced than in North America. El Niño is associated with warm and very wet summer periods (December-February) along the coasts of northern Peru and Ecuador, causing severe flooding whenever the event is severe. The effects during February, March, April may become critical. Southern Brazil and northern Argentina also experience wetter than normal conditions, but mainly during the spring and early summer. The central region of Chile receives mild winters with plenty of rain, and the Peruvian-Bolivian Plateau sometimes experiences winter snowfall, which is unusual for the region. Drier and warm weather observed in the Amazon Basin, Colombia and Central America.

The direct effects of El Niño lead to decreased humidity in Indonesia, increasing the likelihood of forest fires, in the Philippines and northern Australia. Also in June-August, dry weather is observed in the regions of Australia: Queensland, Victoria, New South Wales and eastern Tasmania.

The western Antarctic Peninsula, Ross Land, Bellingshausen and Amundsen seas are covered with large amounts of snow and ice during El Niño. The latter two and the Wedell Sea become warmer and are under higher atmospheric pressure.

In North America, winters are generally warmer than normal in the Midwest and Canada, while central and southern California, northwestern Mexico and the southeastern United States are getting wetter. The Pacific Northwest states, in other words, dry out during El Niño. Conversely, during La Niña, the US Midwest dries out. El Niño is also associated with decreased hurricane activity in the Atlantic.

Eastern Africa, including Kenya, Tanzania and the White Nile Basin, experiences long periods of rain from March to May. Droughts plague southern and central Africa from December to February, mainly Zambia, Zimbabwe, Mozambique and Botswana.

Warm Pool of the Western Hemisphere

A study of climate data showed that in approximately half summer periods After El Niño, there is an unusual warming of the Western Hemisphere Warm Pool. This influences the weather in the region and appears to have a connection to the North Atlantic Oscillation.

Atlantic effect

An El Niño-like effect is sometimes observed in the Atlantic Ocean, where water along the equatorial African coast becomes warmer and water off the coast of Brazil becomes colder. This can be attributed to Volcker circulations over South America.

Non-climatic effects

Along the East Coast South America El Niño reduces the upwelling of cold, plankton-rich water that supports large fish populations, which in turn maintain abundance seabirds, whose droppings support the fertilizer industry.

Local fishing industries along coastlines may experience shortages of fish during prolonged El Niño events. The world's largest fisheries collapse due to overfishing, which occurred in 1972 during El Niño, led to a decline in the Peruvian anchovy population. During the events of 1982-83, populations of southern horse mackerel and anchovies declined. Although the number of shells in warm water increased, the hake went deeper into cold water, and shrimp and sardines went south. But the catch of some other fish species was increased, for example, the common horse mackerel increased its population during warm events.

Changing locations and types of fish due to changing conditions have presented challenges for the fishing industry. The Peruvian sardine has moved towards the Chilean coast due to El Niño. Other conditions have only led to further complications, such as the Chilean government creating fishing restrictions in 1991.

It is postulated that El Niño led to the extinction of the Mochico Indian tribe and other tribes of the pre-Columbian Peruvian culture.

Causes that give rise to El Niño

The mechanisms that may cause El Niño events are still being researched. It is difficult to find patterns that can reveal causes or allow predictions to be made.

History of the theory

The first mention of the term "El Niño" dates back to the year when Captain Camilo Carrilo reported at the Congress of the Geographical Society in Lima that Peruvian sailors called the warm northerly current "El Niño" because it was most noticeable around Christmas. However, even then the phenomenon was interesting only because of its biological impact on the efficiency of the fertilizer industry.

Normal conditions along the western Peruvian coast there is a cold southern current (Peruvian Current) with upwelling water; plankton upwelling leads to active ocean productivity; cold currents lead to a very dry climate on earth. Similar conditions exist everywhere (California Current, Bengal Current). So replacing it with a warm northern current leads to a decrease in biological activity in the ocean and to heavy rains, leading to flooding, on land. An association with flooding was reported in Pezet and Eguiguren.

Towards the end of the nineteenth century there was increased interest in predicting climate anomalies (for food production) in India and Australia. Charles Todd suggested that droughts in India and Australia occur at the same time. Norman Lockyer pointed out the same thing in Gilbert Volcker who first coined the term "Southern Oscillation".

For most of the twentieth century, El Niño was considered a large local phenomenon.

History of the phenomenon

ENSO conditions have occurred every 2-7 years for at least the last 300 years, but most of them have been weak.

Large ENSO events occurred in - , , - , , - , - and - 1998 .

Latest events El Niño occurred in - , - , , , 1997-1998 and -2003.

The 1997-1998 El Niño in particular was strong and brought international attention to the phenomenon, while the 1997-1998 El Niño was unusual in that El Niño occurred very frequently (but mostly weakly).

El Niño in the history of civilization

Scientists tried to establish why, at the turn of the 10th century AD, the two largest civilizations of that time ceased to exist almost simultaneously on opposite ends of the earth. We are talking about the Mayan Indians and the fall of the Chinese Tang Dynasty, which was followed by a period of internecine strife.

Both civilizations were located in monsoon regions, the moisture of which depends on seasonal precipitation. However, at the indicated time, apparently, the rainy season was not able to provide the amount of moisture sufficient for the development Agriculture.

The ensuing drought and subsequent famine led to the decline of these civilizations, researchers believe. They tie climate change With natural phenomenon"El Niño", which refers to temperature fluctuations in eastern surface waters Pacific Ocean in tropical latitudes. This leads to large-scale disturbances in atmospheric circulation, causing droughts in traditionally wet regions and floods in dry ones.

Scientists came to these conclusions by studying the nature of sedimentary deposits in China and Mesoamerica dating back to this period. The last Emperor The Tang Dynasty died in 907 AD, and the last known Mayan calendar dates back to 903.

Literature

Cesar N. Caviedes, 2001. El Niño in History: Storming Through the Ages(University Press of Florida)
Brian Fagan, 1999. Floods, Famines, and Emperors: El Niño and the Fate of Civilizations(Basic Books)
Michael H. Glantz, 2001. Currents of change, ISBN 0-521-78672-X
Mike Davis Late Victorian Holocausts: El Niño Famines and the Making of the Third World(2001), ISBN 1-85984-739-0

Climate, Climatology
Changing of the climate	Paleoclimatology El Niño Geochemical carbon cycle Proterozoic glaciation, Ice Age, Little Ice Age Thermal maximum (

EL NINO CURRENT

EL NINO CURRENT, a warm surface current that sometimes (after about 7-11 years) arises in the equatorial Pacific Ocean and heads towards the South American coast. It is believed that the occurrence of flow is associated with irregular oscillations weather conditions on the globe. The name is given to the current from the Spanish word for the Christ child, as it most often occurs around Christmas. The flow of warm water is preventing plankton-rich cold water from rising to the surface from the Antarctic off the coast of Peru and Chile. As a result, fish are not sent to these areas to feed, and local fishermen are left without a catch. El Niño can also have more far-reaching, sometimes catastrophic, consequences. Its occurrence is associated with short-term fluctuations in climatic conditions around the world; possible drought in Australia and other places, floods and harsh winters in North America, stormy tropical cyclones in the Pacific Ocean. Some scientists have expressed concerns that global warming could cause El Niño to occur more frequently.

The combined influence of land, sea and air on weather conditions sets a certain rhythm of climate change on a scale globe. For example, in the Pacific Ocean (A), winds typically blow from east to west (1) along the equator, -pulling- solar-heated surface layers of water into the basin north of Australia and thereby lowering the thermocline - the boundary between warm surface and cooler deep layers water (2). Over these warm waters, tall cumulus clouds form and produce rain throughout the summer wet season (3). Cooler waters rich in food resources come to the surface off the coast of South America (4), large schools of fish (anchovy) flock to them, and this, in turn, is based on a developed fishing system. The weather over these cold water areas is dry. Every 3-5 years, changes occur in the interaction between the ocean and the atmosphere. The climate pattern is reversed (B) - this phenomenon is called "El Niño". Trade winds either weaken or reverse their direction (5), and warm surface waters that “accumulated” in the western Pacific Ocean flow back, and the water temperature off the coast of South America rises by 2-3°C (6) . As a result, the thermocline (temperature gradient) decreases (7), and all this greatly affects the climate. In the year when El Niño occurs, droughts and forest fires rage in Australia, and floods in Bolivia and Peru. Warm waters off the coast of South America are pushing deeper into the layers of cold water that support plankton, causing the fishing industry to suffer.

Scientific and technical encyclopedic dictionary.

See what “EL NINO CURRENT” is in other dictionaries:

The Southern Oscillation and El Niño (Spanish: El Niño Baby, Boy) is a global ocean-atmospheric phenomenon. As a characteristic feature of the Pacific Ocean, El Niño and La Niña (Spanish: La Niña Baby, Girl) are temperature fluctuations... ... Wikipedia

Not to be confused with Columbus's La Niña caravel. El Niño (Spanish: El Niño Baby, Boy) or Southern Oscillation (English: El Niño/La Niña Southern Oscillation, ENSO) fluctuation in the temperature of the surface layer of water in ... ... Wikipedia

- (El Niño), a warm seasonal surface current in the eastern Pacific Ocean, off the coast of Ecuador and Peru. It develops sporadically in summer when cyclones pass near the equator. * * * EL NINO EL NINO (Spanish: El Nino “Christ Child”), warm... ... encyclopedic Dictionary

Warm surface seasonal current in the Pacific Ocean, off the coast of South America. It appears once every three or seven years after the disappearance of the cold current and lasts for at least a year. Usually originates in December, closer to the Christmas holidays,... ... Geographical encyclopedia

- (El Nino) warm seasonal surface current in the eastern Pacific Ocean, off the coast of Ecuador and Peru. It develops sporadically in the summer when cyclones pass near the equator... Big Encyclopedic Dictionary

El Niño- Anomalous warming of water in the ocean west coast South America, replacing the cold Humboldt Current, which brings heavy rainfall to the coastal areas of Peru and Chile and occurs from time to time as a result of the influence of southeast... ... Dictionary of Geography

- (El Nino) warm seasonal current of surface waters of low salinity in the eastern part of the Pacific Ocean. Distributed in the summer of the Southern Hemisphere along the coast of Ecuador from the equator to 5 7 ° S. w. In some years, E.N. intensifies and... ... Great Soviet Encyclopedia

El Niño- (El Niňo)El Nino, complex climate phenomenon, which occurs irregularly in the equatorial latitudes of the Pacific Ocean. Name E. N. initially referred to the warm ocean current, which annually, usually at the end of December, approaches the shores of the northern... ... Countries of the world. Dictionary

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General overview El Niño is a fluctuation in the temperature of the surface layer of water in the equatorial part of the Pacific Ocean, which has a noticeable effect on the climate. In a narrower sense, El Niño is a phase of the Southern Oscillation in which an area of heated surface water moves eastward. At the same time, trade winds weaken or stop altogether, and upwelling slows down in the eastern part of the Pacific Ocean, off the coast of Peru. The opposite phase of the oscillation is called La Niña.

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First signs of El Niño Increase in air pressure over the Indian Ocean, Indonesia and Australia. Drop in pressure over Tahiti, over the central and eastern parts of the Pacific Ocean. Weakening of trade winds in the South Pacific until they stop and the wind changes direction to the west. Warm air mass in Peru, rains in the Peruvian deserts. This is also the influence of El Nino

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El Niño's influence on climate different regions In South America, the El Niño effect is most pronounced. This phenomenon typically causes warm and very humid summer periods (December to February) along the northern coast of Peru and Ecuador. When El Niño is strong, it causes severe flooding. Southern Brazil and northern Argentina also experience wetter than normal periods, but mainly in the spring and early summer. Central Chile experiences mild winters with plenty of rain, while Peru and Bolivia occasionally experience unusual winter snowfalls for the region.

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Losses and damages More than 15 years ago, when El Niño first showed its character, meteorologists had not yet connected the events of those years: droughts in India, fires in South Africa and hurricanes that tore through Hawaii and Tahiti. Later, when the reasons for these disturbances in nature became clear, the losses brought by the willfulness of the elements were calculated. But it turned out that this is not all. Let's say rains and floods are direct consequences of a natural disaster. But after them came secondary ones - for example, mosquitoes multiplied in new swamps and brought an epidemic of malaria to Colombia, Peru, India, and Sri Lanka. Human bites on the rise in Montana poisonous snakes. They approached settlements, chasing their prey - mice, and they left their settled places due to lack of water, came closer to people and to water.

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From myths to reality Meteorologists' predictions have been confirmed: catastrophic events associated with the El Niño current are hitting the earth one after another. Of course, it is very sad that all this is happening now. But still, it should be noted that for the first time humanity is encountering a global natural disaster, knowing its causes and the course of further development. The El Niño phenomenon is already quite well studied. Science has solved the mystery that plagued Peruvian fishermen. They did not understand why sometimes during the Christmas period the ocean becomes warmer and the shoals of sardines off the coast of Peru disappear. Because the arrival of warm water coincided with Christmas, the current was called El Niño, which means “baby boy” in Spanish. Fishermen, of course, are interested in the immediate reason for the departure of the sardines...

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The fish leave... ...The fact is that sardines feed on phytoplankton. And algae needs sunlight and nutrients - primarily nitrogen, phosphorus. They are found in ocean water, and their supply is top layer constantly replenished by vertical currents coming from the bottom to the surface. But when the El Niño current turns back towards South America, its warm waters “lock” the exit of deep waters. Biogenic elements do not rise to the surface, and algae reproduction stops. The fish leave these places - they do not have enough food.

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Magellan's mistake The first European to swim across largest ocean planet, was Magellan. He called him "The Quiet One". As it soon became clear, Magellan was mistaken. It is in this ocean that most typhoons are born, and it produces three-quarters of the planet's clouds. Now we have also learned that the El Niño current emerging in the Pacific Ocean sometimes causes many different troubles and disasters on the planet...

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El Niño is an elongated tongue of highly heated water. It is equal in area to the United States. Heated water evaporates more intensely and “pumps” the atmosphere with energy faster. El Niño supplies it with 450 million megawatts, which is equivalent to the power of 300,000 large nuclear power plants. It is clear that this energy, according to the law of conservation of energy, does not disappear. And now in Indonesia, disaster broke out in full force. First, there was a raging drought on the island of Sumatra, then the dried-out forests began to burn. In the impenetrable smoke that enveloped the entire island, the plane crashed upon landing, and a tanker and a cargo ship collided at sea. The smoke reached Singapore and Malaysia...

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Years in which El Niño was recorded 1864, 1871, 1877-1878, 1884, 1891, 1899, 1911-1912, 1925-1926, 1939-1941, 1957-1958, 1965-1966, 1972, 1976, 1 982-1983 , 1986-1987, 1992-1993, 1997-1998. , in 1790-1793, 1828, 1876-1878, 1891, 1925-1926, 1982-1983 and 1997-1998, powerful phases of El Niño were recorded, while, for example, in 1991-1992, 1993, 1994 this phenomenon often repeating, it was weakly expressed. El Niño 1997-1998 was so strong that it attracted the attention of the world community and the press.

The Southern Oscillation and El Niño are a global ocean-atmospheric phenomenon. A characteristic feature of the Pacific Ocean, El Niño and La Niña are temperature fluctuations in surface waters in the tropical eastern Pacific Ocean. The names for these phenomena, borrowed from the native Spanish and first coined in 1923 by Gilbert Thomas Volker, mean "baby" and "little one," respectively. Their influence on the climate of the southern hemisphere is difficult to overestimate. The Southern Oscillation (the atmospheric component of the phenomenon) reflects monthly or seasonal fluctuations in the difference in air pressure between the island of Tahiti and the city of Darwin in Australia.

The circulation named after Volcker is a significant aspect of the Pacific phenomenon ENSO (El Nino Southern Oscillation). ENSO is many interacting parts of one global system of ocean-atmospheric climate fluctuations that occur as a sequence of oceanic and atmospheric circulations. ENSO is the world's best known source of interannual weather and climate variability (3 to 8 years). ENSO has signatures in the Pacific, Atlantic and Indian Oceans.

In the Pacific, during significant warm events, El Niño warms up and expands across much of the Pacific tropics and becomes directly correlated with SOI (Southern Oscillation Index) intensity. While ENSO events occur primarily between the Pacific and Indian Oceans, ENSO events in the Atlantic Ocean lag behind the former by 12 to 18 months. Most of the countries that experience ENSO events are developing ones, with economies that are heavily dependent on the agricultural and fishing sectors. New capabilities to predict the onset of ENSO events in three oceans could have global socioeconomic implications. Since ENSO is a global and natural part of the Earth's climate, it is important to know whether changes in intensity and frequency could be a result of global warming. Low frequency changes have already been detected. Interdecadal ENSO modulations may also exist.

El Niño and La Niña

Common Pacific pattern. Equatorial winds collect a warm water pool to the west. Cold waters rise to the surface along the South American coast.

AND La Niña officially defined as long-lasting marine surface temperature anomalies greater than 0.5 °C crossing the central tropical Pacific Ocean. When a condition of +0.5 °C (-0.5 °C) is observed for a period of up to five months, it is classified as an El Niño (La Niña) condition. If the anomaly persists for five months or longer, it is classified as an El Niño (La Niña) episode. The latter occurs at irregular intervals of 2-7 years and usually lasts one or two years.
Increase in air pressure over the Indian Ocean, Indonesia and Australia.
A drop in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean.
Trade winds in the South Pacific are weakening or heading east.
Warm air appears near Peru, causing rain in the deserts.
Warm water spreads from the western part of the Pacific Ocean to the eastern. It brings rain with it, causing it to occur in areas that are usually dry.

Warm El Niño current, consisting of plankton-poor tropical water and heated by its eastern outlet in the Equatorial Current, replaces the cold, plankton-rich waters of the Humboldt Current, also known as the Peruvian Current, which contains large populations of game fish. Most years, the warming lasts only a few weeks or months, after which weather patterns return to normal and fish catches increase. However, when El Niño conditions last for several months, more extensive ocean warming occurs and its economic impact on local fisheries for the external market can be severe.

In the Pacific Ocean, La Niña is characterized by unusually cold temperatures in the eastern equatorial region compared to El Niño, which in turn is characterized by unusually warm temperatures in the same region. Atlantic tropical cyclone activity generally increases during La Niña. A La Niña condition often occurs after an El Niño, especially when the latter is very strong.

Southern Oscillation Index (SOI)

The Southern Oscillation Index is calculated from monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin.

Long-lasting negative SOI values often signal El Niño episodes. These negative values typically accompany continued warming of the central and eastern tropical Pacific, decreased strength of the Pacific trade winds, and decreased rainfall in eastern and northern Australia.

Positive SOI values are associated with strong Pacific trade winds and warming water temperatures in northern Australia, well known as a La Niña episode. The waters of the central and eastern tropical Pacific Ocean become colder during this time. Together this increases the likelihood of more rainfall than normal in eastern and northern Australia.

El Niño influence

As El Niño's warm waters fuel storms, it creates increased precipitation in the east-central and eastern Pacific Ocean.

In South America, the El Niño effect is more pronounced than in North America. El Niño is associated with warm and very wet summer periods (December-February) along the coast of northern Peru and Ecuador, causing severe flooding whenever the event is severe. The effects during February, March, April may become critical. Southern Brazil and northern Argentina also experience wetter than normal conditions, but mainly during the spring and early summer. The central region of Chile receives mild winters with plenty of rain, and the Peruvian-Bolivian Plateau sometimes experiences winter snowfall, which is unusual for the region. Drier and warmer weather is observed in the Amazon Basin, Colombia and Central America.

Direct effects of El Niño leading to decreased humidity in Indonesia, increasing the likelihood of forest fires, in the Philippines and northern Australia. Also in June-August, dry weather is observed in the regions of Australia: Queensland, Victoria, New South Wales and eastern Tasmania.

Warm Pool of the Western Hemisphere. A study of climate data showed that approximately half of the post-El Niño summers experienced unusual warming in the Western Hemisphere Warm Pool. This influences the weather in the region and appears to have a connection to the North Atlantic Oscillation.

Atlantic effect. An El Niño-like effect is sometimes observed in the Atlantic Ocean, where water along the equatorial African coast becomes warmer and water off the coast of Brazil becomes colder. This can be attributed to the Volcker circulation over South America.

Non-climatic effects of El Niño

Along the east coast of South America, El Niño reduces the upwelling of cold, plankton-rich water that supports large populations of fish, which in turn support an abundance of seabirds, whose droppings support the fertilizer industry.

Local fishing industries along coastlines may experience shortages of fish during prolonged El Niño events. The world's largest fisheries collapse due to overfishing, which occurred in 1972 during El Niño, led to a decline in the Peruvian anchovy population. During the events of 1982-83, populations of southern horse mackerel and anchovies declined. Although the number of shells in warm water increased, hake went deeper into cold water, and shrimp and sardines went south. But the catch of some other fish species was increased, for example, the common horse mackerel increased its population during warm events.

It is postulated that El Niño led to the extinction of the Indian Mochico tribe and other tribes of the pre-Columbian Peruvian culture.

Causes that give rise to El Niño

The mechanisms that may cause El Niño events are still being researched. It is difficult to find patterns that can reveal causes or allow predictions to be made.
Bjerknes suggested in 1969 that abnormal warming in the eastern Pacific Ocean could be attenuated by east-west temperature differences, causing weakening in the Volcker circulation and trade winds that move warm water westward. The result is an increase in warm water to the east.
Virtki in 1975 suggested that the trade winds could create a westerly bulge of warm waters, and any weakening of the winds could allow warm waters move east. However, no bulges were noticed on the eve of the events of 1982-83.
Rechargeable Oscillator: Some mechanisms have been proposed that when warm areas are created in the equatorial region, they are dissipated to higher latitudes through El Niño events. The cooled areas are then recharged with heat for several years before the next event occurs.
Western Pacific Oscillator: In the western Pacific Ocean, several weather conditions could cause easterly wind anomalies. For example, a cyclone in the north and an anticyclone in the south result in an easterly wind between them. Such patterns can interact with the westerly flow across the Pacific Ocean and create a tendency for the flow to continue eastward. A weakening of the westerly current at this time may be the final trigger.
The equatorial Pacific Ocean can lead to El Niño-like conditions with a few random variations in behavior. External weather patterns or volcanic activity can be such factors.
The Madden-Julian Oscillation (MJO) is a critical source of variability that may contribute to the sharper evolution leading to El Niño conditions through fluctuations in low-level winds and precipitation over the western and central regions. Pacific Ocean. The eastward propagation of oceanic Kelvin waves may be caused by MJO activity.

History of El Niño

The first mention of the term "El Niño" dates back to 1892, when Captain Camilo Carrilo reported at the Congress of the Geographical Society in Lima that Peruvian sailors called the warm northerly current "El Niño" because it was most noticeable around Christmas. However, even then the phenomenon was interesting only because of its biological impact on the efficiency of the fertilizer industry.

Normal conditions along the western Peruvian coast are a cold southerly current (Peruvian Current) with upwelling water; plankton upwelling leads to active ocean productivity; cold currents lead to a very dry climate on earth. Similar conditions exist everywhere (California Current, Bengal Current). So replacing it with a warm northern current leads to a decrease in biological activity in the ocean and to heavy rains leading to flooding on land. The connection with flooding was reported in 1895 by Pezet and Eguiguren.

Towards the end of the nineteenth century there was increased interest in predicting climate anomalies (for food production) in India and Australia. Charles Todd suggested in 1893 that droughts in India and Australia occur at the same time. Norman Lockyer pointed out the same thing in 1904. In 1924, Gilbert Volcker first coined the term "Southern Oscillation."

For most of the twentieth century, El Niño was considered a large local phenomenon.

The Great El Niño of 1982-83 led to a sharp rise in the interest of the scientific community in this phenomenon.

History of the phenomenon

ENSO conditions have occurred every 2 to 7 years for at least the last 300 years, but most of them have been weak.

Major ENSO events occurred in 1790–93, 1828, 1876–78, 1891, 1925–26, 1982–83, and 1997–98.

The most recent El Niño events occurred in 1986-1987, 1991-1992, 1993, 1994, 1997-1998 and 2002-2003.

The 1997–1998 El Niño in particular was strong and brought international attention to the phenomenon, while what was unusual about the 1990–1994 period was that El Niño occurred very frequently (but mostly weakly).

El Niño in the history of civilization

The mysterious disappearance of the Mayan civilization in Central America could be caused by severe climate changes. This conclusion was reached by a group of researchers from the German National Center for Geosciences, writes the British newspaper The Times.

Scientists tried to establish why, at the turn of the 9th and 10th centuries AD, at opposite ends of the earth, the two largest civilizations of that time ceased to exist almost simultaneously. We are talking about the Mayan Indians and the fall of the Chinese Tang Dynasty, which was followed by a period of internecine strife.

Both civilizations were located in monsoon regions, the moisture of which depends on seasonal precipitation. However, at this time, apparently, the rainy season was not able to provide enough moisture for the development of agriculture.

The ensuing drought and subsequent famine led to the decline of these civilizations, researchers believe. They link climate change to the natural phenomenon El Niño, which refers to temperature fluctuations in the surface waters of the eastern Pacific Ocean in tropical latitudes. This leads to large-scale disturbances in atmospheric circulation, causing droughts in traditionally wet regions and floods in dry ones.

Scientists came to these conclusions by studying the nature of sedimentary deposits in China and Mesoamerica dating back to this period. The last emperor of the Tang Dynasty died in 907 AD, and the last known Mayan calendar dates back to 903.

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