Warm El Niño current. El Niño has been replaced by La Niña: what does it mean. El Niño in the history of civilization

The characteristic oscillation time is from 3 to 8 years, but the strength and duration of El Niño in reality varies greatly. Thus, 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, was weakly expressed. The 1997-1998 El Niño was so strong that it attracted the attention of the world public and the press. At the same time, theories about the connection of the Southern Oscillation with global climate change spread. Since the early 1980s, El Niño also occurred in 1986-1987 and 2002-2003.

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✪ El Niño and La Niña (narrated by oceanographer Vladimir Zhmur)

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Description

Normal conditions along the western coast of Peru are determined by the cold Peruvian Current, which carries water from the south. Where the current turns to the west, along the equator, cold and nutrient-rich waters rise from deep depressions, which contributes to the active development of plankton and other life forms in the ocean. The cold current itself determines the aridity of the climate in this part of Peru, forming deserts. Trade winds drive the heated surface layer of water to the western zone of the tropical part Pacific Ocean, where the so-called tropical warm pool (TTB) is formed. In it, the water is heated to depths of 100-200 m. The Walker atmospheric circulation, manifested in the form of trade winds, coupled with low pressure over the Indonesia region, leads to the fact that in this place the level of the Pacific Ocean is 60 cm higher than in the eastern part. And the water temperature here reaches 29-30 °C versus 22-24 °C off the coast of Peru.

However, everything changes with the onset of El Niño. The trade winds are weakening, the TTB is spreading, and water temperatures are rising across a vast area of ​​the Pacific Ocean. In the region of Peru, the cold current is replaced by a warm water mass moving from the west to the coast of Peru, upwelling weakens, fish die without food, and westerly winds bring moist air masses and rainfall to the deserts, even causing floods. The onset of El Niño reduces the activity of Atlantic tropical cyclones.

History of discovery

The first mention of the term "El Niño" dates back to 1892, when Captain Camilo Carrilo reported at a congress Geographical Society in Lima, that Peruvian sailors called the warm northerly current "El Niño" since it is most noticeable around Christmas time ( El Niño called the Christ Child). In 1893, Charles Todd suggested that droughts in India and Australia were occurring at the same time. Norman Lockyer pointed out the same thing in 1904. The connection between the warm northerly current off the coast of Peru and floods in that country was reported in 1895 by Peset and Eguiguren. The Southern Oscillation was first described in 1923 by Gilbert Thomas Walker. He introduced the terms “Southern Oscillation”, “El Niño” and “La Niña”, and examined the zonal convection circulation in the atmosphere in the equatorial zone of the Pacific Ocean, which now received his name. For a long time Almost no attention was paid to the phenomenon, considering it regional. Only towards the end of the 20th century did the connections between El Niño and the planet’s climate become clear.

Quantitative description

Currently, for a quantitative description of the phenomena, El Niño and La Niña are defined as temperature anomalies of the surface layer of the equatorial part of the Pacific Ocean lasting at least 5 months, expressed in a deviation of water temperature by 0.5 °C higher (El Niño) or lower (La Niña) side.

First signs of El Niño:

1. Increase in air pressure over the Indian Ocean, Indonesia and Australia.
2. A drop in pressure over Tahiti, over the central and eastern Pacific Ocean.
3. Weakening of the trade winds in the South Pacific until they cease and the wind direction changes to the westerly.
4. Warm air mass in Peru, rain in the Peruvian deserts.

In itself, an increase in water temperature off the coast of Peru by 0.5 °C is considered only a condition for the occurrence of El Niño. Typically, such an anomaly can exist for several weeks and then disappear safely. And only a five-month anomaly classified as El Niño phenomenon, can cause significant damage to the region’s economy due to a drop in fish catches.

The Southern Oscillation Index is also used to describe El Niño. It is calculated as the difference in pressure over Tahiti and over Darwin (Australia). Negative index values ​​indicate the El Niño phase, and positive values ​​indicate the La Niña phase.

Early stages and characteristics

The Pacific Ocean is a huge heat-cooling system that causes the movement of air mass systems. Changing Pacific Ocean temperatures affect weather on a global scale. Rain fronts are moving from the western ocean towards the Americas, while drier weather sets in in Indonesia and India.

Although not a direct cause of El Niño, the Madden-Julian Oscillation moves an area of ​​excess precipitation west to east along the tropical belt with a period of 30-60 days, which can influence the rate of development and intensity of El Niño and La Niña in several ways. . For example, air flows from the west, passing between areas of low atmospheric pressure formed by the Madden-Julian oscillation, can trigger the formation of cyclonic circulations north and south of the equator. As these cyclones intensify, westerly winds within the equatorial Pacific also intensify and shift eastward, thus being an integral part in the development of El Niño. The Madden-Julian oscillation may also be a source of propagating east direction Kelvin waves Kelvin wave), which in turn are strengthened by El Niño, leading to a mutually reinforcing effect.

Southern Oscillation

The Southern Oscillation is an atmospheric component of El Niño and represents fluctuations in air pressure in the surface layer of the atmosphere between the waters of the eastern and western parts of the Pacific Ocean. The magnitude of the oscillation is measured using the Southern Oscillation Index. Southern Oscillation Index, SOI). The index is calculated based on the difference in surface air pressure over Tahiti and over Darwin (Australia). El Niño occurred when the index took negative values, which meant a minimal difference in pressure between Tahiti and Darwin.

Low atmospheric pressure usually forms over warm waters, and high atmospheric pressure over cold waters, partly due to the fact that intense convection occurs over warm waters. El Niño is associated with prolonged warm periods in the central and eastern tropical Pacific. This is causing the Pacific trade winds to weaken and rainfall levels to fall over eastern and northern Australia.

Atmospheric Walker circulation

During the period when conditions do not correspond to the formation of El Niño, the Walker circulation is diagnosed near the surface of the earth in the form of easterly trade winds, which move masses of water and air, heated by the sun, to the west. It also promotes upwelling along the coasts of Peru and Ecuador, bringing rich nutrients water close to the surface, increasing the concentration of fish. In the western part of the Pacific Ocean during these periods there is warm, humid weather with low pressure, excess moisture accumulates in typhoons and thunderstorms. As a result of these movements, the sea level in the western part at this time is 60 cm higher.

Impact on the climate of 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. These, for example, happened in January 2011. Southern Brazil and northern Argentina also experience wetter than normal periods, but mostly 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. Drier and warmer weather is observed in the Amazon, Colombia and Central America. Humidity is falling in Indonesia, increasing the likelihood of forest fires. This also applies to the Philippines and northern Australia. From June to August, dry weather occurs in Queensland, Victoria, New South Wales and eastern Tasmania. In Antarctica, the western Antarctic Peninsula, Ross Land, Bellingshausen and Amundsen seas are covered with large amounts of snow and ice. At the same time, the pressure increases and becomes warmer. In North America, winters generally become warmer in the Midwest and Canada. Central and southern California, northwestern Mexico, and the southeastern United States become wetter, while the northwestern Pacific United States becomes drier. During La Niña, on the other hand, the Midwest becomes drier. El Niño also leads to a decrease in Atlantic hurricane activity. East Africa, including Kenya, Tanzania and the White Nile Basin, experiences long rainy seasons from March to May. Droughts plague southern and central Africa from December to February, mainly Zambia, Zimbabwe, Mozambique and Botswana.

An El Niño-like effect is sometimes observed in the Atlantic Ocean, where the water along the equatorial coast of Africa becomes warmer and the water off the coast of Brazil becomes colder. Moreover, there is a connection between this circulation and El Niño.

Impact on health and society

El Niño causes extreme weather conditions associated with epidemic disease frequency cycles. El Niño is associated with an increased risk of mosquito-borne diseases: malaria, dengue fever and Rift Valley fever. Malaria cycles are associated with El Niño in India, Venezuela and Colombia. There is an association with outbreaks of Australian encephalitis (Murray Valley Encephalitis - MVE) occurring in south-eastern Australia following heavy rainfall and flooding caused by La Niña. A notable example is the severe outbreak of Rift Valley fever that occurred due to El Niño following extreme rainfall events in northeastern Kenya and southern Somalia in 1997–98.

It is also believed that El Niño may be associated with the cyclical nature of wars and the emergence of civil conflicts in countries whose climate is influenced by El Niño. A study of data from 1950 to 2004 found that El Niño was associated with 21% of all civil conflicts during that period. Moreover, the risk of civil war during El Niño years is twice as high as during La Niña years. It is likely that the connection between climate and military action is mediated by crop failures, which often occur in hot years.

Recent cases

El Niño was observed from September 2006 to early 2007. The resulting drought in 2007 caused a spike in food prices and associated civil unrest in Egypt, Cameroon and Haiti.

In June 2014, the UK Met Office reported a high probability of El Niño developing in 2014, however, its forecast did not come true. In the fall of 2015, the World Meteorological Organization reported that, coming ahead of schedule and dubbed the “Bruce Lee,” El Niño could become one of the most powerful since 1950. Rain and floods accompanied the Christmas holidays in the USA (along the Mississippi River), in South America (along La Plata) and even in North-West England. In 2016, the influence of El Niño continued.

Notes

1. Scientific Network. El Niño phenomenon
2. Alena Miklashevskaya, Alena Miklashevskaya. The Pacific Ocean is waiting for a cold snap // Kommersant.
3. Tim Liu. El Niño Watch from Space (undefined) . NASA (September 6, 2005). Retrieved May 31, 2010.
4. Stewart, Robert (undefined) . Our Ocean Planet: Oceanography in the 21st Century. Department of Oceanography, Texas A&M University (January 6, 2009). Retrieved July 25, 2009. Archived May 11, 2013.
5. Dr. Tony Phillips. A Curious Pacific Wave (undefined) . National Aeronautics and Space Administration (5 March 2002). Retrieved July 24, 2009. Archived May 11, 2013.
6. Nova. (undefined) . Public Broadcasting Service (1998). Retrieved July 24, 2009. Archived May 11, 2013.
7. De-Zheng Sun. Nonlinear Dynamics in Geosciences: 29 The Role of El Niño-Southern Oscillation in Regulating its Background State . - Springer, 2007. - ISBN 978-0-387-34917-6. - DOI:10.1007/978-0-387-34918-3.
8. Soon-Il An and In-Sik Kang (2000). “A Further Investigation of the Recharge Oscillator Paradigm for ENSO Using a Simple Coupled Model with the Zonal Mean and Eddy Separated” . Journal of Climate. 13 (11): 1987-93. Bibcode:2000JCli...13.1987A. DOI:10.1175/1520-0442(2000)013<1987:AFIOTR>2.0.CO;2 . ISSN 1520-0442 . Access date 2009-07-24.
9. Jon Gottschalck and Wayne Higgins. Madden Julian Oscillation Impacts (undefined) . Climate Prediction Center (USA) Climate Prediction Center) (February 16, 2008). Retrieved July 24, 2009. Archived May 11, 2013.
10. Air-Sea Interaction & Climate. El Niño Watch from Space (undefined) . Jet Propulsion Laboratory California Institute of Technology (September 6, 2005). Retrieved July 17, 2009.

07.12.2007 14:23

Fires and floods, droughts and hurricanes - all hit our Earth in 1997. Fires turned the forests of Indonesia to ashes, then raged across the vast expanses of Australia. Showers have become frequent over the Chilean Atacama Desert, which is particularly dry. Torrential rains and floods did not spare South America. The total damage from the willfulness of the disaster amounted to about $50 billion. Meteorologists believe that the El Niño phenomenon is the cause of all these disasters.

El Niño means "baby" in Spanish. This is the name given to the abnormal warming of the surface waters of the Pacific Ocean off the coast of Ecuador and Peru, which occurs every few years. This affectionate name only reflects the fact that the onset of El Niño most often occurs around the Christmas holidays, and fishermen on the west coast of South America associated it with the name of Jesus in infancy.

In normal years, along the entire Pacific coast of South America, due to the coastal upwelling of cold deep waters caused by the cold surface Peruvian Current, ocean surface temperatures fluctuate within a narrow seasonal range of 15°C to 19°C. During the El Niño period, ocean surface temperatures in the coastal zone increase by 6-10°C. As geological and paleoclimatic studies have shown, the phenomenon mentioned has existed for at least 100 thousand years. Fluctuations in the temperature of the surface layer of the ocean from extremely warm to neutral or cold occur with periods of 2 to 10 years. Currently, the term "El Niño" is used to refer to situations where abnormally warm surface waters occupy not only the coastal region near South America, but also most of the tropical Pacific Ocean up to the 180th meridian.

There is a constant warm current, originating from the coast of Peru and stretching to the archipelago lying southeast of the Asian continent. It is an elongated tongue of heated water, with an area equal to the territory of the United States. The heated water intensively evaporates and “pumps” the atmosphere with energy. Clouds form over the warming ocean. Typically, trade winds (constantly blowing easterly winds in the tropical zone) drive a layer of this warm water from the American coast towards Asia. Around Indonesia, the current stops and monsoon rains begin to fall over southern Asia.

During El Niño near the equator, this current warms up more than usual, so the trade winds weaken or do not blow at all. The heated water spreads to the sides and goes back to the American coast. An anomalous convection zone appears. Rain and hurricanes hit Central and South America. Over the past 20 years, there have been five active El Niño cycles: 1982-83, 1986-87, 1991-1993, 1994-95 and 1997-98.

The La Niño phenomenon, the opposite of El Niño, manifests itself as a decrease in surface water temperature below the climate norm in the eastern tropical zone of the Pacific Ocean. Such cycles were observed in 1984-85, 1988-89 and 1995-96. Unusually cold weather sets in in the eastern Pacific Ocean during this period. During the formation of La Niño, trade winds (easterly) winds from the west coast of the Americas increase significantly. Winds shift the zone of warm water and the “tongue” of cold water stretches for 5000 km, exactly in the place (Ecuador - Samoa Islands) where during El Niño there should be a belt of warm waters. During this period, heavy monsoon rains are observed in Indochina, India and Australia. Countries Caribbean and the United States suffers from droughts and tornadoes. La Niño, like El Niño, most often occurs from December to March. The difference is that El Niño occurs on average once every three to four years, while La Niño occurs once every six to seven years. Both phenomena bring with them increased amount hurricanes, but during La Niño there are three to four times more of them than during El Niño.

According to recent observations, the reliability of the onset of El Niño or La Niño can be determined if:

1. Near the equator, in the eastern Pacific Ocean, a patch of warmer than normal water (El Niño) and colder water (La Niño) forms.

2. The trend is compared atmospheric pressure between the port of Darwin (Australia) and the island of Tahiti. During an El Niño, pressure will be high in Tahiti and low in Darwin. During La Niño it is the other way around.

Research over the past 50 years has established that El Niño is more than just coordinated fluctuations in surface pressure and ocean temperature. El Niño and La Niño are the most pronounced manifestations of interannual climate variability on a global scale. These phenomena represent large-scale changes in ocean temperatures, precipitation, atmospheric circulation, and vertical air movements over the tropical Pacific Ocean.

Abnormal weather on the globe during El Niño years

In the tropics, there is an increase in precipitation over areas east of the central Pacific Ocean and a decrease from normal over northern Australia, Indonesia and the Philippines. In December-February, precipitation above normal is observed along the coast of Ecuador, in northwestern Peru, over southern Brazil, central Argentina and over the equatorial, eastern part of Africa, during June-August in the western United States and over central Chile.

El Niño events are also responsible for large-scale air temperature anomalies around the world. During these years there are outstanding temperature rises. Warmer than normal conditions in December-February were above southeast Asia, over Primorye, Japan, the Sea of ​​Japan, over southeastern Africa and Brazil, southeastern Australia. Warmer than normal temperatures occur in June-August along the western coast of South America and over southeastern Brazil. Colder winters (December-February) occur along the southwest coast of the United States.

Abnormal weather conditions on the globe during La Niño years

During La Niño periods, precipitation increases over the western equatorial Pacific, Indonesia and the Philippines, and is almost completely absent over the eastern part. More precipitation falls in December-February across northern South America and over South Africa, and in June-August over south-eastern Australia. Drier than normal conditions are observed over the coast of Ecuador, over northwestern Peru and the equatorial part East Africa during December-February, and over southern Brazil and central Argentina in June-August. There are large-scale aberrations across the world, with the largest number of areas experiencing abnormally cool conditions. Cold winters in Japan and the Maritimes, over southern Alaska and western, central Canada. Cool summer seasons over southeast Africa, India and southeast Asia. More warm winters over the southwestern USA.

Some aspects of teleconnection

Although the main events associated with El Niño occur in the tropical zone, they are closely related to processes occurring in other regions Globe. This can be seen in long-distance communications across territory and time - teleconnections. During El Niño years, energy transfer into the troposphere of tropical and temperate latitudes increases. This is manifested in an increase in thermal contrasts between tropical and polar latitudes, an intensification of cyclonic and anticyclonic activity in temperate latitudes. The DVNIIGMI carried out calculations of the frequency of cyclones and anticyclones in the northern part of the Pacific Ocean from 120° east. up to 120° W It turned out that cyclones in the band 40°-60° N. and anticyclones in the band 25°-40° N. is formed in subsequent winters after El Niño more than in previous ones, i.e. processes in winter months after El Niño are characterized by greater activity than before this period.

During El Niño years:

1. the Honolulu and Asian anticyclones are weakened;

2. the summer depression over southern Eurasia is filled, which is the main reason for the weakening of the monsoon over India;

3. The summer depression over the Amur basin is more developed than usual, as well as the winter Aleutian and Icelandic depressions.

On the territory of Russia during El Niño years, areas of significant air temperature anomalies are identified. In spring, the temperature field is characterized by negative anomalies, that is, spring in El Niño years is usually cold in most of Russia. In summer, a center of negative anomalies remains over Far East and Eastern Siberia, and over Western Siberia and European part In Russia, pockets of positive air temperature anomalies appear. In the autumn months, no significant air temperature anomalies were identified over the territory of Russia. It should only be noted that in the European part of the country the temperature background is slightly lower than usual. El Niño years experience warm winters over most of the area. The focus of negative anomalies can be traced only over the northeast of Eurasia.

We are currently in a weakening period of the El Niño cycle - a period of average ocean surface temperature distribution. (El Niño and La Niño represent opposite extremes of ocean water pressure and temperature cycles.)

Over the past few years, great strides have been made in the comprehensive study of the El Niño phenomenon. Scientists believe that the key issues in this problem are the oscillations of the atmosphere-ocean-Earth system. In this case, the atmospheric oscillations are the so-called Southern Oscillation (coordinated fluctuations in surface pressure in the subtropical anticyclone in the southeast Pacific Ocean and in the trough stretching from northern Australia to Indonesia), ocean oscillations - the El Niño and La Niño phenomena and the Earth oscillations - movement of geographic poles. Also of great importance when studying the El Niño phenomenon is the study of the impact of external cosmic factors on the Earth's atmosphere.

Especially for Primpogoda, the leading weather forecasters of the Weather Forecast Department of the Primorsky UGMS T. D. Mikhailenko and E. Yu. Leonova

El Niño

Southern Oscillation And El Niño(Spanish) El Niño- Baby, Boy) is a global ocean-atmospheric phenomenon. Being a characteristic feature of the 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 people 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 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

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:

1. Increase in air pressure over the Indian Ocean, Indonesia and Australia.
2. A drop in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean.
3. Trade winds in the South Pacific are weakening or heading east.
4. Warm air appears near Peru, causing rain in the deserts.
5. 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.

The warm El Niño current, composed of plankton-poor tropical water and heated by its easterly flow in the Equatorial Current, replaces the cold, plankton-rich waters of the Humboldt Current, also known as the Peruvian Current, which supports 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.

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 unusual cold temperature in the eastern equatorial region compared to El Niño, which in turn is characterized by unusually high 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.

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 warmer weather is observed in the Amazon Basin, Colombia and Central America.

The direct effects of El Niño are reducing humidity in Indonesia, increasing the likelihood of wildfires, 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 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.

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 are a cold southerly current (Peru 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 .

The last El Niño events 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. It's about 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, in specified time, apparently, the rainy season was not able to provide enough moisture for development 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.

Links

• The El Nino Theme Page Explains El Nino and La Nina, provides real time data, forecasts, animations, FAQ, impacts and more.
• The International Meteorological Organization announced the detection of the beginning of the event La Niña in the Pacific Ocean. (Reuters/YahooNews)

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

The first time I heard the word “El Niño” was in the United States in 1998. At that time, this natural phenomenon was well known to Americans, but almost unknown in our country. And it’s not surprising, because El Niño originates in the Pacific Ocean off the coast of South America and greatly influences the weather in the southern states of the United States. El Niño(translated from Spanish El Niño- baby, boy) in the terminology of climatologists - one of the phases of the so-called Southern Oscillation, i.e. fluctuations in the temperature of the surface layer of water in the equatorial Pacific Ocean, during which the area of ​​heated surface water shifts to the east. (For reference: the opposite phase of oscillation - the displacement of surface waters to the west - is called La Niña (La Nina- baby, girl)). The El Niño phenomenon, which occurs periodically in the ocean, greatly affects the climate of the entire planet. One of the largest El Niño events occurred in 1997-1998. It was so strong that it attracted the attention of the world community and the press. At the same time, theories about the connection of the Southern Oscillation with global climate change spread. According to experts, the warming phenomenon El Niño is one of the main driving forces of natural variability in our climate.

In 2015 The World Meteorological Organization said the premature El Niño, dubbed the “Bruce Lee,” could be one of the strongest since 1950. Its appearance was expected last year, based on data on rising air temperatures, but these models did not materialize, and El Niño did not manifest itself.

In early November, the American agency NOAA (National Oceanic and Atmospheric Administration) released a detailed report on the state of the Southern Oscillation and analyzed the possible development of El Niño in 2015-2016. The report is published on the NOAA website. The conclusions of this document state that currently there are all conditions for the formation of El Niño, average temperature surface of the equatorial Pacific Ocean (SST) has increased values ​​and continues to increase. The probability that El Niño will develop throughout the winter of 2015-2016 is 95% . A gradual decline of El Niño is predicted in the spring of 2016. The report published an interesting graph showing the change in SST since 1951. The blue areas correspond to cooler temperatures (La Niña), orange high temperatures are shown (El Niño). The previous strong increase in SST of 2°C was observed in 1998.

Data obtained in October 2015 indicate that the SST anomaly at the epicenter already reaches 3 °C.

Although causes of El Niño have not yet been fully explored, it is known that it begins with the trade winds weakening over several months. A series of waves move across the Pacific Ocean along the equator and create a body of warm water off South America, where the ocean normally has low temperatures due to the rise of deep ocean waters to the surface. Weakening trade winds coupled with strong westerly winds could also create a pair of cyclones (south and north of the equator), which is another sign of a future El Niño.

While studying the causes of El Niño, geologists noticed that the phenomenon occurs in the eastern part of the Pacific Ocean, where a powerful rift system has formed. American researcher D. Walker found a clear connection between increased seismicity on the East Pacific Rise and El Niño. Russian scientist G. Kochemasov saw another curious detail: the relief fields of ocean warming almost one to one repeat the structure of the earth's core.

One of the interesting versions belongs to the Russian scientist - Doctor of Geological and Mineralogical Sciences Vladimir Syvorotkin. It was first expressed back in 1998. According to the scientist, powerful centers of hydrogen-methane degassing are located in hot spots of the ocean. Or simply - sources of constant release of gases from the bottom. Their visible signs are exits thermal waters, black and white smokers. In the area of ​​the coast of Peru and Chile, during El Niño years there is a massive release of hydrogen sulfide. The water is boiling and there is a terrible smell. At the same time, an amazing power is pumped into the atmosphere: approximately 450 million megawatts.

The El Niño phenomenon is now being studied and discussed more and more intensively. A team of researchers from the German National Center for Geosciences has concluded that the mysterious disappearance of the Mayan civilization in Central America may have been caused by strong climate change caused by El Niño. At the turn of the 9th and 10th centuries AD, the two largest civilizations of that time ceased to exist on opposite ends of the earth 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, a time came when the rainy season was unable to provide sufficient moisture for the development of agriculture. The drought and subsequent famine led to the decline of these civilizations, researchers believe. 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.

Climatologists and meteorologists say that El Niño2015, which will peak between November 2015 and January 2016, will be one of the strongest. El Niño will lead to large-scale disturbances in atmospheric circulation, which could cause droughts in traditionally wet regions and floods in dry ones.

A phenomenal phenomenon, which is considered one of the manifestations of the developing El Niño, is now observed in South America. The Atacama Desert, which is located in Chile and is one of the driest places on Earth, is covered with flowers.

This desert is rich in deposits of nitrate, iodine, table salt and copper; for four centuries there has been no significant precipitation. The reason is that the Peruvian Current cools the lower layers of the atmosphere and creates a temperature inversion that prevents precipitation. Rain falls here once every few decades. However, in 2015, the Atacama was hit by unusually heavy rainfall. As a result, dormant bulbs and rhizomes (horizontally growing underground roots) sprouted. The faded plains of the Atacama were covered with yellow, red, violet and white flowers - nolans, beaumaries, rhodophials, fuchsias and hollyhocks. The desert first bloomed in March, after unexpectedly intense rains caused flooding in the Atacama and killed about 40 people. Now the plants have bloomed for the second time in a year, before the start of the southern summer.

What will El Niño 2015 bring? A powerful El Niño is expected to bring welcome rainfall to dry areas of the United States. In other countries, its effect may be the opposite. In the western Pacific Ocean, El Niño creates high atmospheric pressure, bringing dry and sunny weather to large areas of Australia, Indonesia, and sometimes even India. The impact of El Niño on Russia has so far been limited. It is believed that under the influence of El Niño in October 1997, temperatures in Western Siberia reached above 20 degrees, and then they started talking about the retreat of permafrost to the north. In August 2000, Emergencies Ministry specialists attributed the series of hurricanes and rainstorms that swept across the country to the impact of the El Niño phenomenon.

At all times, the yellow press has increased its ratings due to various news of a mystical, catastrophic, provocative or revealing nature. However, in Lately More and more people are beginning to be frightened by various natural disasters, the ends of the world, etc. In this article we will talk about one natural phenomenon, which sometimes borders on mysticism - the warm current of El Niño. What is this? This question is often asked by people on various Internet forums. Let's try to answer it.

Natural phenomenon El Niño

In 1997-1998 One of the largest natural disasters associated with this phenomenon in the entire history of observations took place on our planet. This mysterious phenomenon caused a lot of noise and attracted close attention from the world's media. mass media, and his name is for the phenomenon, the encyclopedia will tell. In scientific terms, El Niño is a complex of changes in the chemical and thermobaric parameters of the atmosphere and ocean, taking on the character natural disaster. As you can see, the definition is very difficult to understand, so let’s try to look at it with our eyes ordinary person. The reference literature says that El Niño is just a warm current that sometimes occurs off the coast of Peru, Ecuador and Chile. Scientists cannot explain the nature of the appearance of this current. The name of the phenomenon itself comes from the Spanish language and means “baby.” El Niño got its name due to the fact that it appears only at the end of December and coincides with Catholic Christmas.

Normal situation

In order to understand the anomalous nature of this phenomenon, let us first consider the usual climate situation in this region of the planet. Everyone knows that mild weather in Western Europe The warm Gulf Stream determines the current, while in the Pacific Ocean of the Southern Hemisphere the tone is set by the cold Antarctic. The prevailing Atlantic winds here are the trade winds, which blow on the western South American coast, crossing the high Andes, leaving all the moisture on the eastern slopes. As a result, the western part of the mainland is a rocky desert where rainfall is extremely rare. However, when the trade winds pick up so much moisture that they can transport it across the Andes, they form a powerful surface current here, which causes a surge of water off the coast. The attention of specialists was attracted by the colossal biological activity of this region. Here, in a relatively small area, annual fish production exceeds the global total by 20%. This also leads to an increase in fish-eating birds in the region. And in places where they accumulate, a colossal mass of guano (dung) - a valuable fertilizer - is concentrated. In some places the thickness of its layers reaches 100 meters. These deposits became the object of industrial production and export.

Catastrophe

Now let's look at what happens when the warm El Niño current appears. In this case, the situation changes dramatically. An increase in temperature leads to mass death or loss of fish and, as a result, birds. Next, there is a drop in atmospheric pressure in the eastern part of the Pacific Ocean, clouds appear, trade winds subside, and the winds change their direction to the opposite. As a result, torrents of water fall on the western slopes of the Andes, floods, floods, and mudslides rage here. And on the opposite side of the Pacific Ocean - in Indonesia, Australia, New Guinea - a terrible drought begins, which leads to forest fires and destruction of agricultural plants. However, the El Niño phenomenon is not limited to this: “red tides”, which are caused by the growth of microscopic algae, begin to develop from the Chilean coast to California. It would seem that everything is clear, but the nature of the phenomenon is not completely clear. Thus, oceanographers consider the appearance of warm waters to be a consequence of a change in winds, and meteorologists explain the change in winds by the heating of waters. What kind of vicious circle is this? However, let's look at some things that climate scientists have missed.

Degassing El Niño scenario

What kind of phenomenon this is, geologists helped to figure it out. For ease of understanding, we will try to move away from specific scientific terms and tell everything in a generally accessible language. It turns out that El Niño forms in the ocean above one of the most active geological sections of the rift system (the rift earth's crust). Hydrogen is actively released from the depths of the planet, which, upon reaching the surface, forms a reaction with oxygen. As a result, heat arises, which warms the water. In addition, this also leads to the appearance of over the region, which also contributes to more intense heating of the ocean by solar radiation. Most likely, the role of the Sun is decisive in this process. All this leads to an increase in evaporation, a decrease in pressure, as a result of which a cyclone is formed.

Biological productivity

Why is there such high biological activity in this region? Scientists estimate that it corresponds to the heavily fertilized ponds in Asia and is more than 50 times higher than in other parts of the Pacific Ocean. Traditionally, this is usually explained by the wind driving warm waters from the coast - upwelling. As a result of this process, cold water, enriched with nutrients (nitrogen and phosphorus), rises from the depths. And when El Niño appears, upwelling is interrupted, as a result of which birds and fish die or migrate. It would seem that everything is clear and logical. However, here too, scientists do not say much. For example, the mechanism for rising water from the depths of the ocean slightly Scientists measure temperatures at various depths oriented perpendicular to the shore. Then graphs (isotherms) are constructed, comparing the level of coastal and deep waters, and the above-mentioned conclusions are drawn from this. However, measuring the temperature in coastal waters is incorrect, because it is known that their coldness is determined by the Peruvian Current. And the process of constructing isotherms across the coastline is incorrect, because the prevailing winds blow along it.

But the geological version easily fits into this scheme. It has long been known that the water column of this region has a very low oxygen content (the reason is a geological discontinuity) - lower than anywhere on the planet. And the upper layers (30 m), on the contrary, are abnormally rich in it due to the Peruvian Current. It is in this layer (above the rift zones) that unique conditions for the development of life are created. When the El Niño current appears, degassing in the region increases, and the thin surface layer is saturated with methane and hydrogen. This leads to the death of living beings, and not at all the lack of food supply.

Red tides

However, with the onset of an environmental disaster, life here does not stop. They begin to actively reproduce in the water unicellular algae- dinoflagellates. Their red color is protection from solar ultraviolet radiation (we already mentioned that an ozone hole forms over the region). Thus, thanks to the abundance of microscopic algae, many marine organisms that act as ocean filters (oysters, etc.) become poisonous, and eating them leads to severe poisoning.

The model is confirmed

Let's consider an interesting fact that confirms the reality of the degassing version. American researcher D. Walker carried out work to analyze sections of this underwater ridge, as a result of which he came to the conclusion that during the years of El Niño, seismic activity sharply increased. But it has long been known that it is often accompanied by increased degassing of the subsoil. So, most likely, scientists simply confused cause and effect. It turns out that the changed direction of El Niño is a consequence, not the cause of subsequent events. This model is also supported by the fact that during these years the water literally boils with the release of gases.

La Niña

This is the name given to the final phase of El Niño, which results in a sharp cooling of the water. A natural explanation for this phenomenon is the destruction of the ozone layer over Antarctica and the Equator, which causes and leads to an influx of cold water in the Peruvian Current, which cools El Niño.

Root cause in space

The media blames El Niño for the floods in South Korea, unprecedented frosts in Europe, droughts and fires in Indonesia, destruction of the ozone layer, etc. However, if we remember the fact that the mentioned current is just a consequence of geological processes occurring in the bowels of the Earth, then we should think about the root cause. And it is hidden in the influence on the core of the planet of the Moon, the Sun, the planets of our system, as well as other celestial bodies. So it’s useless to blame El Niño...