Ocean current El Niño. El Niño phenomenon. Southern Oscillation and its consequences. Non-climatic effects of El Niño

Phenomenon La Nina ("girl" in Spanish)) is characterized by an anomalous decrease in water surface temperature in the central and eastern part of the tropical Pacific Ocean. This process is the reverse of El Nino ("boy"), which, on the contrary, is associated with warming in the same zone. These states replace each other with a frequency of about a year.

Both El Niño and La Niña influence circulation patterns of ocean and atmospheric currents, which in turn influence weather and climate throughout to the globe, causing droughts in some regions, hurricanes and heavy rains in others.

After a period of neutrality in the El Niño-La Niña cycle observed in mid-2011, tropical zone The Pacific Ocean began to cool in August, and a weak to moderate La Niña has been observed from October until now.

"Forecasts made on the basis mathematical models, and their expert interpretation suggests that La Niña is close to maximum strength, and will likely begin to slowly weaken in the coming months. However, existing methods do not allow predicting the situation beyond May, so it is unclear what situation will develop in the Pacific Ocean - whether it will be El Niño, La Niña or a neutral situation,” the report says.

Scientists note that La Niña 2011-2012 was significantly weaker than in 2010-2011. Models predict that temperatures in the Pacific Ocean will approach neutral levels between March and May 2012.

El Niño(Spanish) El Niño— Baby, Boy) or Southern Oscillation(English) El Niño/La Niña - Southern Oscillation, ENSO ) 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 — phase of the Southern Oscillation, in which the area of ​​heated surface waters shifts to the east. 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 oscillation is called La Niña(Spanish) La Nina— Baby, Girl). 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. El Niño 1997-1998 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. Since the early 1980s, El Niño also occurred in 1986–1987 and 2002–2003.

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 plankton-rich waters rise from deep depressions, which contributes to the active development of life 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 into western zone tropical part of the 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 blood pressure over the Indonesian region, leads to the fact that in this place the level of the Pacific Ocean is 60 cm higher than in its 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 They bring humid air masses and rainfall to the deserts, even causing floods. The onset of El Niño reduces the activity of Atlantic tropical cyclones.

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" because it is most noticeable around Christmas. In 1893, Charles Todd suggested that droughts in India and Australia were occurring at the same time. Norman Lockyer also 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 phenomena of the Southern Oscillation were 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. The connection between El Niño and the planet’s climate has been clarified.

El Niño 1997 (TOPEX)

Quantitative description

Currently, to quantitatively describe the phenomena, El Niño and La Niña are defined as temperature anomalies surface layer of the equatorial part of the Pacific Ocean for a duration of at least 5 months, expressed in a deviation of water temperature by 0.5 °C upward (El Nino) or downward (La Nina).

First signs of El Niño:

1. Increase in air pressure above Indian Ocean, Indonesia and Australia.
2. A drop in pressure over Tahiti, over the central and eastern parts of the 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. But only five-month anomaly classified as an El Niño event, can cause significant damage to the region’s economy due to a drop in fish catches.

Also used to describe El Niño Southern Oscillation Index(English) Southern Oscillation Index, SOI ). It is calculated as the difference in pressure over Tahiti and over Darwin (Australia). Negative values index indicate about the El Niño phase, and positive ones - about La Niña .

The influence of El Niño on the climate of various 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. This, for example, happened in January 2011. Southern Brazil and northern Argentina also experience wetter than usual 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. Drier and warm weather observed in the Amazon basin, Colombia and Central America. Humidity decreases 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 are generally getting warmer in the Midwest and Canada. Central and southern California, northwestern Mexico and the southeastern United States are becoming wetter, while the Pacific Northwest states are becoming drier. During La Niña, on the other hand, the Midwest becomes drier. El Niño also leads to reduced Atlantic hurricane activity. Eastern 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 effect similar to El Niño is sometimes observed in 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 of El Niño on health and society

El Niño causes extreme weather associated with cycles in the incidence of epidemic diseases. 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 has been 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 striking example is a 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. At the same time, the risk of civil war in El Niño years it is twice as high as in 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.

The La Niña phenomenon is an anomalous cooling of the surface in the central and eastern parts of the tropical Pacific Ocean in winter. According to Japanese meteorologists, the most low temperatures were recorded in mid-February, but by early March the indicators had returned to normal levels. According to weather forecasters, this is a sign of the imminent final approach to the fall - at least in Japan, located in the Pacific Ocean. Experts are currently studying the possibility of an opposite phenomenon, El Niño, occurring in the coming summer, which is characterized by an anomalous increase in water temperatures in the Pacific Ocean.

Typically La Niña will bring heavy rainfall and tropical storms to the West Coast South America, in Southeast Asia and in the eastern part of equatorial Africa. Nevertheless, this phenomenon can influence the weather on a global scale. In particular, this winter the phenomenon became one of the factors that led to severe cold in Europe, ITAR-TASS reports.

The La Nina phenomenon (La Nina, "the girl" in Spanish) is characterized by an anomalous decrease in surface water temperature in the central and eastern part of the tropical Pacific Ocean. This process is the opposite of El Niño (El Nino, “the boy”), which, on the contrary, is associated with warming in the same zone. These states replace each other with a frequency of about a year.

Following a period of neutrality in the El Niño–La Niña cycle observed in mid-2011, the tropical Pacific began to cool in August and has experienced weak to moderate La Niña from October to date. By early April, La Niña had completely disappeared, and neutral conditions are still observed in the equatorial Pacific, experts write.

“(Analysis of modeling results) suggests that La Niña is unlikely to return this year, while the probabilities of remaining neutral and El Niño occurring in the second half of the year are approximately equal,” the WMO said.

Both El Niño and La Niña influence circulation patterns of ocean and atmospheric currents, which in turn influence weather and climate across the globe, causing droughts in some regions and hurricanes and heavy rainfall in others.
Message from 05/17/2012

The La Niña climate phenomenon that occurred in 2011 was so strong that it ultimately caused global sea levels to drop by as much as 5 mm. With the advent of La Niña, there was a shift in Pacific surface temperatures and changes in precipitation patterns around the world, as terrestrial moisture began to leave the ocean and be directed to land in the form of rain in Australia, northern South America, and Southeast Asia .

The alternating dominance of the warm oceanic phase of the Southern Oscillation, El Niño, and the cold phase, La Niña, can change global sea levels so dramatically, but satellite data inexorably indicates that global levels have The waters still rise to a height of about 3 mm.

As soon as El Niño arrives, the rise in water levels begins to occur faster, but with a change in phases almost every five years, a diametrically opposite phenomenon is observed. The strength of the effect of a particular phase also depends on other factors and clearly reflects the general climate change towards its harshness. Many scientists around the world are studying both phases of the southern oscillation, as they contain many clues to what is happening on Earth and what awaits it.

A moderate to strong La Niña atmospheric phenomenon will continue in the tropical Pacific until April 2011. This is according to an El Niño/La Niña advisory issued on Monday by the World Meteorological Organization.

As the document highlights, all model-based forecasts predict a continuation or possible intensification of the La Niña phenomenon over the next 4-6 months, ITAR-TASS reports.

La Niña, which this year formed in June-July, replacing the El Niño phenomenon that ended in April, is characterized by unusually low water temperatures in the central and eastern equatorial parts of the Pacific Ocean. It disrupts normal routines. tropical precipitation and atmospheric circulation. El Niño is exactly the opposite phenomenon, which is characterized by unusual high temperatures waters in the Pacific Ocean.

The effects of these phenomena can be felt in many parts of the planet, expressed in floods, storms, droughts, increases or, conversely, decreases in temperatures. La Niña usually leads to heavy downpours in the eastern equatorial Pacific, Indonesia, the Philippines and severe droughts in Ecuador, northwestern Peru and eastern equatorial Africa.

La Niña, which may increase in intensity and continue until the end of this year or the beginning of next year.

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.

The term "El Niño" was first used in 1892 at the congress of the Geographical Society in Lima. Captain Camilo Carrilo said that the name “El Niño” was given to the warm northerly current by Peruvian sailors, as it is best seen on Christmas Day. In 1923, Gilbert Thomas Walker began studying the zonal convection circulation of the atmosphere in the equatorial zone of the Pacific Ocean and introduced the terms “Southern Oscillation”, “El Niño” and “La Niña”. His work remained known only in narrow circles until the end of the twentieth century, until the connection between El Niño and climate change was established.

El Niño means "baby" in Spanish. This affectionate name only reflects the fact that the onset of El Niño most often occurs around the Christmas holiday, and fishermen along the west coast of South America associated it with the name of Jesus as a baby.

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 extending 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. Arises anomalous zone convection. 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. The countries of the Caribbean and the United States are suffering 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 part of the Pacific Ocean, a patch of warmer water than usual (El Niño) and colder water (La Niño) forms.
2. The atmospheric pressure trend between the port of Darwin (Australia) and the island of Tahiti is compared. 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, vertical air movements over the tropical Pacific Ocean.

Abnormal weather conditions 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 over south-east Asia, over Primorye, Japan, Sea of ​​Japan, above southeast Africa and Brazil, south-eastern 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 occur over the coast of Ecuador, over northwestern Peru and equatorial eastern Africa during December-February, and over southern Brazil and central Argentina during June-August. There are large-scale abnormalities occurring around the world, with the largest number 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.

sources

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 reported that the emerging ahead of schedule and dubbed the "Bruce Lee" El Niño 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 thermal water outlets, 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. 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, the time came when rainy season was unable to provide sufficient moisture for development 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 temperature inversion which 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, Western Siberia the temperature settled 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.

Can you imagine such a picture in the underground passage of your city?
But in vain. In our life everything is possible, and even more!
Temperatures are rising, the climate is changing, rivers are overflowing their banks, water levels in the world's oceans are rising, and scammers are skimming the cream off people's fears. Global warming And global example then the premiere of the film "". What is the connection with cards, you might think?
And here she is!

Recent sea level data from NASA (using the Jason-2 oceanography satellite) indicate that large-scale, persistent weakening of winds in the western and central equatorial Pacific during October caused a strong, moving east direction wave of warm water. In the central and eastern equatorial Pacific, this warm wave appears as an area of ​​more high level sea, compared to normal and warmer sea surface temperatures.
The image was created using data collected by the US/European satellite during a 10-day period spanning late October and early November. The picture shows a red and white area in the central and eastern equatorial Pacific Ocean that is approximately 10 to 18 centimeters above normal. These areas contrast with the western equatorial Pacific, where lower water levels (blue and purple areas) are between 8 to 15 centimeters below normal. Along the equator, red and white colors represent areas where sea ​​temperatures surfaces one to two degrees Celsius above normal.

These are many interacting parts of one global system of ocean-atmospheric climate fluctuations that occur as a sequence of oceanic and atmospheric circulations. It is the world's best known source of interannual weather and climate variability (3 to 8 years).

Signs of El Niño are as follows:
Increase in air pressure over the Indian Ocean, Indonesia and Australia.
Warm air appears near Peru, causing rain in the deserts.
Warm water spreads from the western part of the Pacific Ocean to the eastern part. It brings rain with it, causing it to occur in areas that are usually dry.
As El Niño's warm waters fuel storms, it creates increased rainfall in the east-central and eastern Pacific Ocean.
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.
Based on this data, I can write new script for a smashing blockbuster. As usual: apocalypse, catastrophe, panic... El Niño 2029 or El Niño 2033. Nowadays it’s fashionable to invent everything with numbers. Or, perhaps simply.
El Nin o-o

After a period of neutrality in the El Niño-La Niña cycle observed in mid-2011, the tropical Pacific began to cool in August, with weak to moderate La Niña observed from October to date.

“Mathematical model forecasts and expert interpretation suggest that La Niña is close to maximum strength and is likely to slowly weaken in the coming months. However, existing methods do not allow predicting the situation beyond May, so it is unclear what situation will develop in the Pacific Ocean - whether it will be El Niño, La Niña or a neutral situation,” the report says.

Scientists note that La Niña 2011-2012 was significantly weaker than in 2010-2011. Models predict that temperatures in the Pacific Ocean will approach neutral levels between March and May 2012.

La Niña 2010 was accompanied by a decrease in cloud cover and increased trade winds. The decrease in pressure led to heavy rain in Australia, Indonesia and Southeast Asia. In addition, according to meteorologists, it is La Niña that is responsible for heavy rains in southern and drought in eastern equatorial Africa, as well as for the drought situation in the central regions of southwest Asia and South America.

El Niño (Spanish El Niño - Baby, Boy) or Southern Oscillation (English El Niño/La Niña - Southern Oscillation, ENSO) 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 oscillation is called La Niña (Spanish: La Niña - Baby, Girl). 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. El Niño 1997-1998 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. Since the early 1980s, El Niño also occurred in 1986-1987 and 2002-2003.

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 plankton-rich waters rise from deep depressions, which contributes to the active development of life 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 into the western zone of the tropical 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 Indonesian region, leads to the fact that in this place the level of the Pacific Ocean is 60 cm higher than in its 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.

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. In 1893, Charles Todd suggested that droughts in India and Australia were occurring at the same time. Norman Lockyer also 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 phenomena of the Southern Oscillation were 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. The connection between El Niño and the planet’s climate has been clarified.

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:

Increase in air pressure over the Indian Ocean, Indonesia and Australia.

A drop in pressure over Tahiti, over the central and eastern parts of the Pacific Ocean.

Weakening of the trade winds in the South Pacific until they cease and the wind direction changes to the westerly.
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 an El Niño phenomenon, can cause significant damage to the region’s economy due to a drop in fish catches.

The Southern Oscillation Index (SOI) 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.

INFLUENCE OF EL NINO 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. This, for example, happened in January 2011. Southern Brazil and northern Argentina also experience wetter than usual 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. 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 are becoming wetter, while the Pacific Northwest states are becoming drier. During La Niña, on the other hand, the Midwest becomes drier. El Niño also leads to a decrease in Atlantic hurricane activity. Eastern 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 water along the equatorial coast of Africa becomes warmer and water off the coast of Brazil becomes colder. Moreover, there is a connection between this circulation and El Niño.

INFLUENCE OF EL NINO ON HEALTH AND SOCIETY

El Niño causes extreme weather conditions associated with cycles in the incidence of epidemic diseases. 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.

The La Niña climate phenomenon, associated with a drop in water temperatures in the equatorial Pacific Ocean and affecting weather patterns across almost the entire globe, has disappeared and is not likely to return until the end of 2012, the World Meteorological Organization (WMO) said.

The La Nina phenomenon (La Nina, “the girl” in Spanish) is characterized by an anomalous decrease in surface water temperature in the central and eastern part of the tropical Pacific Ocean. This process is the opposite of El Niño (El Nino, “the boy”), which, on the contrary, is associated with warming in the same zone. These states replace each other with a frequency of about a year.

After a period of neutrality in the El Niño-La Niña cycle observed in mid-2011, the tropical Pacific began to cool in August, with weak to moderate La Niña observed from October to date. By early April, La Niña had completely disappeared, and neutral conditions are still observed in the equatorial Pacific, experts write.

“(Analysis of modeling results) suggests that La Niña is unlikely to return this year, while the probabilities of remaining neutral and El Niño occurring in the second half of the year are approximately equal,” the WMO said.

Both El Niño and La Niña influence circulation patterns of ocean and atmospheric currents, which in turn influence weather and climate across the globe, causing droughts in some regions and hurricanes and heavy rainfall in others.

The La Niña climate phenomenon that occurred in 2011 was so strong that it ultimately caused global sea levels to drop by as much as 5 mm. With the advent of La Niña, there was a shift in Pacific surface temperatures and changes in precipitation patterns around the world, as terrestrial moisture began to leave the ocean and be directed to land in the form of rain in Australia, northern South America, and Southeast Asia .

The alternating dominance of the warm oceanic phase of the Southern Oscillation, El Niño, and the cold phase, La Niña, can change global sea levels so dramatically, but satellite data inexorably indicates that global levels have The waters still rise to a height of about 3 mm.
As soon as El Niño arrives, the rise in water levels begins to occur faster, but with a change in phases almost every five years, a diametrically opposite phenomenon is observed. The strength of the effect of a particular phase also depends on other factors and clearly reflects the general climate change towards its harshness. Many scientists around the world are studying both phases of the southern oscillation, as they contain many clues to what is happening on Earth and what awaits it.

A moderate to strong La Niña atmospheric phenomenon will continue in the tropical Pacific until April 2011. This is according to an El Niño/La Niña advisory issued on Monday by the World Meteorological Organization.

As the document highlights, all model-based forecasts predict a continuation or possible intensification of the La Niña phenomenon over the next 4-6 months, ITAR-TASS reports.

La Niña, which this year formed in June-July, replacing the El Niño phenomenon that ended in April, is characterized by unusually low water temperatures in the central and eastern equatorial parts of the Pacific Ocean. This disrupts normal tropical precipitation and atmospheric circulation patterns. El Niño is the opposite phenomenon, characterized by unusually high water temperatures in the Pacific Ocean.

The effects of these phenomena can be felt in many parts of the planet, expressed in floods, storms, droughts, increases or, conversely, decreases in temperatures. Typically, La Niña results in heavy winter rainfall in the eastern equatorial Pacific, Indonesia, and the Philippines, and severe droughts in Ecuador, northwestern Peru, and eastern equatorial Africa.
In addition, the phenomenon contributes to a decrease in global temperatures, and this is most noticeable from December to February in northeastern Africa, Japan, southern Alaska, central and western Canada, and southeastern Brazil.

The World Meteorological Organization (WMO) said today in Geneva that in August of this year, the La Niña climate phenomenon was again observed in the equator region of the Pacific Ocean, which may increase in intensity and continue until the end of this year or the beginning of next year.

The latest WMO report on El Niño and La Niña phenomena states that the current La Niña event will peak later this year, but the intensity will be less than what it was in the second half of 2010. Due to its uncertainty, WMO invites countries in the Pacific region to closely monitor its development and promptly report on possible droughts and floods due to it.

The La Niña phenomenon refers to the phenomenon of an anomalous long-term large-scale cooling of water in the eastern and central parts of the Pacific Ocean near the equator, which gives rise to a global climate anomaly. The previous La Niña event led to spring drought along the western Pacific coast, including China.