El Niño phenomena are characteristic of the ocean. Climatic phenomena La Nina and El Nino, and their impact on health and society
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 the cause of all these disasters is El Niño phenomenon.
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 during the Christmas holidays, and fishermen west coast South America associated him 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 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. 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. Unusual cold weather established 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 events bring with them an increased number of hurricanes, but La Niño has three to four times as many hurricanes as 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 in 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 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, 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 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 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. Warmer winters over the southwestern United States.
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El Niño- a natural phenomenon that is associated with global changes in climatic conditions occurring on Earth.
El Niño brings with it natural disasters, destruction and misfortune. Scientists have found that this natural phenomenon destroyed more than one civilization of the past.
Scientific circles have determined that the interaction of ocean currents and air masses are quite stable, but from time to time failures occur in this system, the causes of which have not been established.
As a result, the direction of air flows and water masses changes, which in turn entails an increase in temperature in the surface layer of the ocean near the coast by up to 10 degrees. A failure necessarily brings catastrophic changes in the climate: prolonged droughts, endless rains, floods.
- The frequency of El Niño is approximately 10 years.
La Niña is a phenomenon that is the direct opposite of El Niño. Feature– decrease in water temperature in the eastern Pacific Basin. This gives rise to tornadoes, drought, rains and floods.
Scientists have proven the destructive role of El Niño. American archaeologists have found that the disappearance of a particular species of mollusks and the appearance of others is an indicator of climate fluctuations.
Scientists, observing the movement of mollusks, have confirmed that when El Niño occurs, and accordingly, when the temperature of the water surface increases, some species of mollusks quickly die, while others move south. After studying mollusk shells, scientists found that in ancient times, this natural phenomenon occurred extremely rarely compared to the present time.
For scientific world The mystery of the disappearance of the Olmec civilization, which existed in the 14th-13th centuries, remains relevant. V. BC, the region of residence of which roughly corresponded to the borders of modern Mexico.
The Olmecs built monumental structures. But around the 5th century BC, the Olmecs suddenly stopped their construction, buried huge stone heads and disappeared into the swamps around their cities.
Scientists suggest that the death of the Olmec civilization is associated with the next El Niño.
Also, according to scientists, the Moche culture, which appeared around the beginning of the 2nd century BC in the northern coastal region of Peru, fell victim to the natural phenomenon of El Niño.
The Moche Indians are famous for building huge buildings from bricks, the raw materials of which were dried in the sun. This civilization is well known to scientists for its characteristic gold and ceramic products. Archaeologists have examined a pyramid near Trujillo, built during the Moche culture. Approximately a hundred skeletons were discovered buried under a thick layer of silt.
- This indicates that a major flood occurred at that time.
However, scientists do not rule out the fact that the human remains found could be the result of a sacrificial ritual. The Moche Indians believed that this act would turn away from them the impending flood caused by the next El Niño.
A natural phenomenon Scientists classify El Niño/La Niña as a global catastrophe that radically changes the climate: in some parts of the planet it rains incessantly, leading to real floods, while in other parts of the Earth severe droughts occur, plunging people into famine.
So, several hundred years ago, a severe drought occurred, which caused the complete destruction of the Anasazi Indian culture that existed in southwestern Colorado. The Anasazi Indians built stone houses. But sometime around 1150 AD. the stone housing was abandoned for unknown reasons. Modern scientists conducted a study of the found remains of Indians and came to the conclusion that most of the Indians were simply eaten.
During the research, scientists were able to establish that cannibalism flourished within the territory of the Anasazi Indians.
Scientists believe that the cannibalism of that time was a consequence of the raging drought that drove other tribes from their habitats. In search of food, other tribes came to the territory of the Anasazi Indians, but they did not find anything edible here either. The source of their food was the local residents - the Anasazi Indians.
- Around 1200, the drought subsided, and with it cannibalism.
German scientists from the National Center for Geosciences made a discovery - the world civilizations of Central America, the Mayans and the Tang Dynasty of China, became victims of the global El Niño. Despite the fact that these civilizations were located in different parts of our planet, they died almost simultaneously.
The reason that caused the death of civilizations was the severe drought that prevailed in the 9th and 10th centuries. V. AD
The mystery of the El Niño phenomenon has not yet been completely solved. However, it is clear that it is almost impossible to defeat such a formidable opponent. A person can only rely on modern technologies and on a system of mutual assistance between countries.
Author: S. Gerasimov
On April 18, 1998, the newspaper “World of News” published an article by N. Varfolomeeva “Moscow snowfall and the mystery of the El Niño phenomenon” which stated: “...We have not yet learned to be scared at the word El Niño... It is El Niño that is a threat to life on the planet ... The El Niño phenomenon has been practically unstudied, its nature is unclear, it cannot be predicted, which means it is, in the full sense of the word, a time bomb... If efforts are not immediately made to clarify the nature of this strange phenomenon, humanity cannot be sure of the future " Agree that all this looks quite ominous, it’s just scary. Unfortunately, everything that is described in the newspaper is not fiction, not a cheap sensation to increase the circulation of the publication. El Niño is a real unpredictable natural phenomenon - a warm current so affectionately named.
"El Niño" means "baby" in Spanish. a little boy" This tender name originated in Peru, where local fishermen have long been faced with an incomprehensible mystery of nature: in other years, the water in the ocean suddenly heats up and moves away from the shores. And this happens just before Christmas. That's why the Peruvians connected their miracle with the Christian mystery of Christmas: in Spanish, El Niño is the name for the Holy Child Christ. True, before it did not bring such troubles as it does now. Why does a phenomenon sometimes demonstrate its full strength, while in other cases it shows almost no effect? And what caused the Peruvian miracle, the consequences of which are very serious and sad?
For 20 years now, an entire scientific army has been exploring the space between Indonesia and South America. 13 meteorological vessels, replacing each other, are constantly in these waters. Many buoys are equipped with instruments to measure water temperature from the surface to a depth of 400 meters. Seven planes and five satellites are patrolling the skies over the ocean to get an overall picture of the state of the atmosphere, including understanding the mysterious natural phenomenon El Niño. This occasionally occurring warm current off the coast of Peru and Ecuador is associated with the occurrence of unfavorable weather disasters around the world. It is difficult to follow it - this is not the Gulf Stream, stubbornly moving along a set route for thousands of years. And El Niño occurs, like a jack-in-the-box, every three to seven years. From the outside it looks like this: from time to time in the Pacific Ocean - from the coast of Peru all the way to the islands of Oceania - a very warm giant current appears, with a total area equal to the area of the United States - about 100 million km2. It extends into a long, tapering sleeve. Over this vast space, as a result of increased evaporation, colossal energy is pumped into the atmosphere. The El Niño effect releases energy with a capacity of 450 million megawatts, which is equal to the total capacity of 300 thousand large nuclear power plants. It's like one more thing - an extra one - the Sun rises from the Pacific Ocean, heating our planet! And then here, as if in a giant cauldron, between America and Asia, the signature climatic dishes of the year are cooked.
Naturally, the first to celebrate its “birth” are Peruvian fishermen. They are concerned about the disappearance of schools of sardines off the coast. The immediate reason for the departure of the fish lies, as it turns out, in the disappearance of food. Sardines, and not only them, feed on phytoplankton, component which are microscopic algae. And algae needs sunlight and nutrients, primarily nitrogen and phosphorus. They are present in ocean water, and their supply in the upper layer is constantly replenished by vertical currents going from the bottom to the surface. But when the El Niño current turns back towards South America, its warm waters “lock” the exit of deep waters. Biogenic elements do not rise to the surface, and algae reproduction stops. The fish leave these places - they do not have enough food. But sharks appear. They also react to “problems” in the ocean: bloodthirsty robbers are attracted by the water temperature - it rises by 5-9 ° C. It is precisely this sharp increase in the temperature of the surface layer of water in the eastern Pacific Ocean (in the tropical and central parts) that is the El phenomenon. Niño. What's happening to the ocean?
In normal years, warm surface ocean waters are transported and retained by easterly winds - the trade winds - in the western zone of the tropical Pacific Ocean, where the so-called tropical warm pool (TTB) is formed. It should be noted that the depth of this warm layer of water reaches 100-200 meters. The formation of such a huge heat reservoir is the main necessary condition for the birth of El Niño. At the same time, as a result of the surge of water, the sea level off the coast of Indonesia is two feet higher than off the coast of South America. At the same time, the water surface temperature in the west in the tropical zone averages +29-30° C, and in the east +22-24° C. A slight cooling of the surface in the east is the result of the rise of deep cold waters to the ocean surface due to water suction trade winds. At the same time, the largest region of heat and stationary unstable equilibrium in the ocean-atmosphere system is formed above the TTB in the atmosphere (when all forces are balanced and the TTB is motionless).
For unknown reasons, once every three to seven years the trade winds suddenly weaken, the balance is upset and the warm waters of the western basin rush east, creating one of the strongest warm currents in the World Ocean. Over a vast area in the eastern Pacific Ocean, in the tropical and central equatorial parts, there is a sharp increase in the temperature of the surface layer of the ocean. This is the onset of El Niño. Its beginning is marked by a long onslaught of squally westerly winds. They replace the usual weak trade winds over warm western part Pacific Ocean and block the rise of cold deep waters to the surface, that is, the normal circulation of water in the World Ocean is disrupted. Unfortunately, such a scientific, dry explanation of the causes is nothing compared to the consequences.
But then a giant “baby” was born. His every “breath”, every “wave of his little hand” causes processes that are global in nature. El Niño is usually accompanied by environmental disasters: droughts, fires, heavy rains, causing flooding of vast areas of densely populated areas, which leads to the death of people and the destruction of livestock and crops in different regions of the Earth. El Niño also has a significant impact on the state of the global economy. According to American experts, in 1982-1983 the economic damage from his “pranks” in the USA amounted to 13 billion dollars and from one and a half to two thousand people died, and according to the estimates of the world’s leading insurance company Munich Re, the damage in 1997-1998 is estimated at already 34 billion dollars and 24 thousand human lives.
Drought and rain, hurricanes, tornadoes and snowfalls are the main satellites of El Niño. All this, as if on command, falls to the Earth in unison. During his “coming” in 1997-1998, fires turned rainforests Indonesia to ashes, and then raged across the vast expanses of Australia. They reached the outskirts of Melbourne. The ashes flew to New Zealand - 2000 kilometers away. Tornadoes swept through places where they had never been. Sunny California was attacked by “Nora” - a tornado (as a tornado is called in the USA) of unprecedented size - 142 kilometers in diameter. He rushed over Los Angeles, almost tearing the roofs off the Hollywood film studios. Two weeks later, another tornado, Pauline, struck Mexico. The famous resort of Acapulco was attacked by ten-meter ocean waves - buildings were destroyed, the streets were littered with debris, garbage and beach furniture. The floods did not spare South America either. Hundreds of thousands of Peruvian peasants fled from the onset of water that fell from the sky, their fields were lost, flooded with mud. Where streams used to gurgle, turbulent streams rushed through. The Chilean Atacama Desert, which has always been so unusually dry that NASA tested its Mars rover there, was hit by torrential rains. Catastrophic floods were also observed in Africa.
In other parts of the planet, climate turmoil has also brought misfortune. In New Guinea, one of the largest islands on the planet, mainly in its eastern part, the land is cracked by heat and drought. Tropical greenery dried up, wells were left without water, crops died. Half a thousand people died of hunger. There was a threat of a cholera epidemic.
Usually a “little boy” frolics for about 18 months, so the planet has time to change seasons several times. It makes itself felt not only in summer, but also in winter. And if at the turn of 1982-1983 in the village of Paradise (USA) 28 m 57 cm of snow fell in a year, then in winter season 1998/99, thanks to the El Niño phenomenon, drifts of 29 meters 13 cm grew in a few days at the ski base on Mount Baker.
And if you think that these cataclysms do not affect the vast expanses of Europe, Siberia or Far East, then you are deeply mistaken. Everything that happens in the Pacific Ocean reverberates throughout the planet. This is a monstrous snowfall in Moscow, and 11 floods of the Neva - a record for three hundred years of the existence of St. Petersburg, and +20 ° C in October in Western Siberia. It was then that scientists began to speak with alarm about the retreat of the border permafrost on North.
And if earlier meteorologists and other specialists did not know what caused such a “collapse” in the weather, now the cause of all disasters is considered to be the return movement of the El Niño current in the Pacific Ocean. They study it up and down, but cannot squeeze it into any framework. Scientists just shrug their shoulders - this is anomalous climate phenomenon.
And what’s most interesting is that they paid attention to this phenomenon only in the last 100 years. But, as it turns out, the mysterious El Niño has existed for many millions of years. Thus, archaeologist M. Moseli claims that 1100 years ago a powerful current, or rather, the rivers generated by it natural disasters, destroyed the system of irrigation canals and thereby destroyed the highly developed culture of a large state in Peru. Humanity simply had not previously associated these natural disasters with it. Scientists began to carefully analyze everything connected with the “baby”, and even studied his “pedigree”.
The Huon Peninsula in the area of the island of New Guinea was chosen to reveal the secrets of El Niño. It consists of a series of terraces coral reef. Part of this island is constantly rising due to tectonic movement, and thus bringing to the surface samples of coral reef that are approximately 130,000 years old. Analysis of isotopic and chemical data from these ancient corals helped scientists identify 14 climate “windows” of 20-100 years each. Cold (40,000 years ago) and warm periods (125,000 years ago) were analyzed in order to assess the characteristics of the flow in different climatic regimes. The coral samples obtained indicate that El Nino used to be not as intense as it has been in the last hundred years. Here are the years in which its anomalous activity was recorded: 1864,1871,1877-1878,1884,1891,1899,1911-1912, 1925-1926, 1939-1941, 1957-1958, 1965-1966, 1972, 1976, 1982 -1983, 1986-1987, 1992-1993, 1997-1998, 2002-2003. As you can see, the El Niño “phenomenon” is happening more often, lasting longer and causing more and more trouble. The periods from 1982 to 1983 and from 1997 to 1998 are considered the most intense.
The discovery of the El Niño phenomenon is considered the event of the century. After extensive research, scientists have discovered that the warm western basin typically enters an opposite phase, called La Niña, a year after an El Niño, when the eastern Pacific Ocean cools 5 degrees Celsius below average. Then recovery processes begin to take effect, bringing cold fronts to the western North American coast, accompanied by hurricanes, tornadoes and thunderstorms. That is, the destructive forces continue their work. It was noted that 13 El Niño periods accounted for 18 La Niña phases. Scientists were only able to verify that the distribution of TTB anomalies in the study area does not correspond to normal and therefore the empirical probability of the occurrence of La Niña is 1.7 times greater than the probability of the occurrence of El Niño.
The causes and increasing intensity of reverse currents still remain a mystery to researchers. Climatologists often benefit from historical materials in their research. Australian scientist William de la Mare, having studied old reports from whalers from 1931 to 1986 (when whaling was banned), determined that the hunt, as a rule, ended at the edge of the forming ice. Figures show that the summer ice limit from the mid-fifties to the early seventies shifted in latitude by 3°, that is, approximately 1000 kilometers to the south (we are talking about the Southern Hemisphere). This result coincides with the opinion of scientists who recognize warming globe as a result of human activity. German scientist M. Latif from the Institute of Meteorology in Hamburg suggests that the disturbing influence of El Niño is increasing due to the increasing greenhouse effect on Earth. Unpleasant news about rapid warming is coming from the shores of Alaska: the glacier has become hundreds of meters thinner, salmon have changed their spawning time, beetles that have multiplied due to the heat are devouring the forest. Both polar caps of the planet are causing concern among scientists. However, representatives of science did not agree on the answer to the global question: does the “greenhouse effect” in the Earth’s atmosphere affect the intensity of El Niño?
But experts have learned to predict the arrival of the “baby.” And perhaps that is the only reason why the damage of the last two cycles did not have such tragic consequences. Thus, a group of Russian scientists from the Obninsk Institute of Experimental Meteorology, led by V. Pudov, proposed a new approach to predicting El Niño. They decided to develop the already known idea that the emergence of flow is associated with the development tropical cyclones in the Philippine Sea area. Both typhoons and El Niño are consequences of the accumulation of excess heat in the surface layer of the ocean. The difference between these phenomena is in scale: typhoons release excess heat many times a year, and El Niño - once every few years. It was also noticed that before El Niño forms, the ratio of atmospheric pressure always changes in two points: in Tahiti and in Darwin, Australia. It was precisely this fluctuation in the pressure ratio that turned out to be stable sign, by which meteorologists can now learn in advance about the approach of the “menacing baby.”
edited news VENDETTA - 20-10-2010, 13:02
EL NINO CURRENT
EL NINO CURRENT, a warm surface current that sometimes (after about 7-11 years) arises in the equatorial Pacific Ocean and heads towards the South American coast. It is believed that the occurrence of flow is associated with irregular oscillations weather conditions on the globe. The name is given to the current from the Spanish word for the Christ child, as it most often occurs around Christmas. The flow of warm water is preventing plankton-rich cold water from rising to the surface from the Antarctic off the coast of Peru and Chile. As a result, fish are not sent to these areas to feed, and local fishermen are left without a catch. El Niño can also have more far-reaching, sometimes catastrophic, consequences. Its occurrence is associated with short-term fluctuations in climatic conditions Worldwide; possible drought in Australia and other places, floods and harsh winters in North America, stormy tropical cyclones in the Pacific Ocean. Some scientists have expressed concerns that global warming could cause El Niño to occur more frequently.
The combined influence of land, sea and air on weather conditions sets a certain rhythm of climate change on a global scale. For example, in the Pacific Ocean (A), winds typically blow from east to west (1) along the equator, -pulling- solar-heated surface layers of water into the basin north of Australia and thereby lowering the thermocline - the boundary between warm surface layers and cooler deeper layers water (2). Over these warm waters, tall cumulus clouds form and produce rain throughout the summer wet season (3). Cooler waters rich in food resources come to the surface off the coast of South America (4), large schools of fish (anchovy) flock to them, and this, in turn, is based on a developed fishing system. The weather over these cold water areas is dry. Every 3-5 years, changes occur in the interaction between the ocean and the atmosphere. The climate pattern is reversed (B) - this phenomenon is called "El Niño". Trade winds either weaken or reverse their direction (5), and warm surface waters that “accumulated” in the western Pacific Ocean flow back, and the water temperature off the coast of South America rises by 2-3°C (6) . As a result, the thermocline (temperature gradient) decreases (7), and all this greatly affects the climate. In the year when El Niño occurs, droughts and forest fires rage in Australia, and floods in Bolivia and Peru. Warm waters off the coast of South America are pushing deeper into the layers of cold water that support plankton, causing the fishing industry to suffer.
Scientific and technical encyclopedic dictionary.
See what “EL NINO CURRENT” is in other dictionaries:
Southern Oscillation and El Niño (Spanish: El Niño Baby, Boy) is a global ocean atmospheric phenomenon. Being characteristic feature Pacific Ocean, El Niño and La Niña (Spanish: La Niña Baby, Girl) are temperature fluctuations... ... Wikipedia
Not to be confused with Columbus's La Niña caravel. El Niño (Spanish: El Niño Baby, Boy) or Southern Oscillation (English: El Niño/La Niña Southern Oscillation, ENSO) fluctuation in the temperature of the surface layer of water in ... ... Wikipedia
- (El Niño), a warm seasonal surface current in the eastern Pacific Ocean, off the coast of Ecuador and Peru. It develops sporadically in summer when cyclones pass near the equator. * * * EL NINO EL NINO (Spanish: El Nino “Christ Child”), warm... ... encyclopedic Dictionary
Warm surface seasonal current in the Pacific Ocean, off the coast of South America. It appears once every three or seven years after the disappearance of the cold current and lasts for at least a year. Usually originates in December, closer to the Christmas holidays,... ... Geographical encyclopedia
- (El Nino) warm seasonal surface current in the eastern Pacific Ocean, off the coast of Ecuador and Peru. It develops sporadically in the summer when cyclones pass near the equator... Big Encyclopedic Dictionary
El Niño- Anomalous warming of ocean water off the west coast of South America, replacing the cold Humboldt Current, which brings heavy rainfall to the coastal areas of Peru and Chile and occurs from time to time as a result of the influence of southeastern... ... Dictionary of Geography
- (El Nino) warm seasonal current of surface waters of low salinity in the eastern part of the Pacific Ocean. Distributed in the summer of the Southern Hemisphere along the coast of Ecuador from the equator to 5 7 ° S. w. In some years, E.N. intensifies and... ... Great Soviet Encyclopedia
El Niño- (El Niňo)El Nino, a complex climatic phenomenon that occurs irregularly in the equatorial latitudes of the Pacific Ocean. Name E. N. initially referred to the warm ocean current, which annually, usually at the end of December, approaches the shores of the northern... ... Countries of the world. Dictionary
The circulation named after Volcker is a significant aspect of the Pacific phenomenon ENSO (El Nino Southern Oscillation). ENSO is many interacting parts of one global system of ocean-atmospheric climate fluctuations that occur as a sequence of oceanic and atmospheric circulations. ENSO is the world's best known source of interannual weather and climate variability (3 to 8 years). ENSO has signatures in the Pacific, Atlantic and Indian Oceans.
In the Pacific, during significant warm events, El Niño warms up and expands across much of the Pacific tropics and becomes directly correlated with SOI (Southern Oscillation Index) intensity. While ENSO events are primarily between the Pacific and Indian Oceans, ENSO events in Atlantic Ocean are 12-18 months behind the first ones. Most of the countries that experience ENSO events are developing ones, with economies that are heavily dependent on the agricultural and fishing sectors. New capabilities to predict the onset of ENSO events in three oceans could have global socioeconomic implications. Since ENSO is a global and natural part of the Earth's climate, it is important to know whether changes in intensity and frequency could be a result of global warming. Low frequency changes have already been detected. Interdecadal ENSO modulations may also exist.
El Niño and La Niña
Common Pacific pattern. Equatorial winds collect a warm water pool to the west. Cold waters rise to the surface along the South American coast.AND La Niña officially defined as long-lasting marine surface temperature anomalies greater than 0.5 °C crossing the central tropical Pacific Ocean. When a condition of +0.5 °C (-0.5 °C) is observed for a period of up to five months, it is classified as an El Niño (La Niña) condition. If the anomaly persists for five months or longer, it is classified as an El Niño (La Niña) episode. The latter occurs at irregular intervals of 2-7 years and usually lasts one or two years.
Increase in air pressure over the Indian Ocean, Indonesia and Australia.
A drop in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean.
Trade winds in the South Pacific are weakening or heading east.
Warm air appears near Peru, causing rain in the deserts.
Warm water spreads from the western part of the Pacific Ocean to the eastern. It brings rain with it, causing it to occur in areas that are usually dry.
Warm El Niño current, consisting of plankton-poor tropical water and heated by its eastern flow in the Equatorial Current, replaces the cold, plankton-rich waters of the Humboldt Current, also known as the Peruvian Current, which contains large populations commercial fish. Most years, the warming lasts only a few weeks or months, after which weather patterns return to normal and fish catches increase. However, when El Niño conditions last for several months, more extensive ocean warming occurs and its economic impact on local fisheries for the external market can be severe.
The Volcker circulation is visible on the surface as easterly trade winds, which move water and air heated by the sun westward. It also creates oceanic upwelling off the coasts of Peru and Ecuador, bringing cold plankton-rich waters to the surface, increasing fish populations. The western equatorial Pacific Ocean is characterized by warm, humid weather and low atmospheric pressure. The accumulated moisture falls in the form of typhoons and storms. As a result, in this place the ocean is 60 cm higher than in its eastern part.
In the Pacific Ocean, La Niña is characterized by unusual cold temperature in the eastern equatorial part compared to El Niño, which, in turn, is characterized by unusual high temperature 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-term negative values SOIs often signal El Niño episodes. These negative values typically accompany continued warming of the central and eastern tropical Pacific, decreased strength of the Pacific trade winds, and decreased rainfall in eastern and northern Australia.
Positive values SOIs are associated with strong Pacific trade winds and warming water temperatures in northern Australia, well known as a La Niña episode. The waters of the central and eastern tropical Pacific Ocean become colder during this time. Together this increases the likelihood of more rainfall than normal in eastern and northern Australia.
El Niño influence
As El Niño's warm waters fuel storms, it creates increased precipitation in the east-central and eastern Pacific Ocean.In South America, the El Niño effect is more pronounced than in North America. El Niño is associated with warm and very wet summer periods (December-February) along the coast of northern Peru and Ecuador, causing severe flooding whenever the event is severe. The effects during February, March, April may become critical. Southern Brazil and northern Argentina also experience wetter than normal conditions, but mainly during spring and early summer. The central region of Chile receives mild winters with plenty of rain, and the Peruvian-Bolivian Plateau sometimes experiences winter snowfall, which is unusual for the region. Drier and warm weather observed in the Amazon Basin, Colombia and Central America.
Direct effects of El Niño lead to decreased humidity in Indonesia, increasing the likelihood of forest fires, in the Philippines and northern Australia. Also in June-August, dry weather is observed in the regions of Australia: Queensland, Victoria, New South Wales and eastern Tasmania.
The western Antarctic Peninsula, Ross Land, Bellingshausen and Amundsen seas are covered with large amounts of snow and ice during El Niño. The latter two and the Wedell Sea become warmer and are under higher atmospheric pressure.
In North America, winters are generally warmer than normal in the Midwest and Canada, while central and southern California, northwestern Mexico and the southeastern United States are getting wetter. The Pacific Northwest states, in other words, dry out during El Niño. Conversely, during La Niña, the US Midwest dries out. El Niño is also associated with decreased hurricane activity in the Atlantic.
Eastern Africa, including Kenya, Tanzania and the White Nile Basin, experiences long periods of rain from March to May. Droughts plague southern and central Africa from December to February, mainly Zambia, Zimbabwe, Mozambique and Botswana.
Warm Pool of the Western Hemisphere. A study of climate data showed that approximately half of the post-El Niño summers experienced unusual warming in the Western Hemisphere Warm Pool. This influences the weather in the region and appears to have a connection to the North Atlantic Oscillation.
Atlantic effect. An El Niño-like effect is sometimes observed in the Atlantic Ocean, where water along the equatorial African coast becomes warmer and water off the coast of Brazil becomes colder. This can be attributed to the Volcker circulation over South America.
Non-climatic effects of El Niño
Along the east coast of South America, El Niño reduces the upwelling of cold, plankton-rich water that supports large populations of fish, which in turn support an abundance of seabirds, whose droppings support the fertilizer industry.Local fishing industries along coastlines may experience shortages of fish during prolonged El Niño events. The world's largest fisheries collapse due to overfishing, which occurred in 1972 during El Niño, led to a decline in the Peruvian anchovy population. During the events of 1982-83, populations of southern horse mackerel and anchovies declined. Although the number of shells in warm water increased, the hake went deeper into cold water, and shrimp and sardines went south. But the catch of some other fish species was increased, for example, the common horse mackerel increased its population during warm events.
Changing locations and types of fish due to changing conditions have presented challenges for the fishing industry. The Peruvian sardine has moved towards the Chilean coast due to El Niño. Other conditions have only led to further complications, such as the Chilean government creating fishing restrictions in 1991.
It is postulated that El Niño led to the extinction of the Indian Mochico tribe and other tribes of the pre-Columbian Peruvian culture.
Causes that give rise to El Niño
The mechanisms that may cause El Niño events are still being researched. It is difficult to find patterns that can reveal causes or allow predictions to be made.Bjerknes suggested in 1969 that abnormal warming in the eastern Pacific Ocean could be attenuated by east-west temperature differences, causing weakening in the Volcker circulation and trade winds that move warm water westward. The result is an increase in warm water to the east.
Virtky in 1975 suggested that the trade winds could create a westerly bulge of warm waters, and any weakening of the winds could allow warm waters to move east. However, no bulges were noticed on the eve of the events of 1982-83.
Rechargeable Oscillator: Some mechanisms have been proposed that when warm areas are created in the equatorial region, they are dissipated to higher latitudes through El Niño events. The cooled areas are then recharged with heat for several years before the next event occurs.
Western Pacific Oscillator: In the western Pacific Ocean, several weather conditions could cause easterly wind anomalies. For example, a cyclone in the north and an anticyclone in the south result in an easterly wind between them. Such patterns can interact with the westerly flow across the Pacific Ocean and create a tendency for the flow to continue eastward. A weakening of the westerly current at this time may be the final trigger.
The equatorial Pacific Ocean can lead to El Niño-like conditions with a few random variations in behavior. External weather patterns or volcanic activity can be such factors.
The Madden-Julian Oscillation (MJO) is a critical source of variability that may contribute to the sharper evolution leading to El Niño conditions through fluctuations in low-level winds and precipitation over the western and central regions. Pacific Ocean. The eastward propagation of oceanic Kelvin waves may be caused by MJO activity.
History of El Niño
The first mention of the term "El Niño" dates back to 1892, when Captain Camilo Carrilo reported at the Congress of the Geographical Society in Lima that Peruvian sailors called the warm northerly current "El Niño" because it was most noticeable around Christmas. However, even then the phenomenon was interesting only because of its biological impact on the efficiency of the fertilizer industry.Normal conditions along the western Peruvian coast are a cold southerly current (Peruvian Current) with upwelling water; plankton upwelling leads to active ocean productivity; cold currents lead to a very dry climate on earth. Similar conditions exist everywhere (California Current, Bengal Current). So replacing it with a warm northern current leads to a decrease in biological activity in the ocean and to heavy rains leading to flooding on land. The connection with flooding was reported in 1895 by Pezet and Eguiguren.
Towards the end of the nineteenth century there was increased interest in predicting climate anomalies (for food production) in India and Australia. Charles Todd suggested in 1893 that droughts in India and Australia occur at the same time. Norman Lockyer pointed out the same thing in 1904. In 1924, Gilbert Volcker first coined the term "Southern Oscillation."
For most of the twentieth century, El Niño was considered a large local phenomenon.
The Great El Niño of 1982-83 led to a sharp rise in the interest of the scientific community in this phenomenon.
History of the phenomenon
ENSO conditions have occurred every 2 to 7 years for at least the last 300 years, but most of them have been weak.
Major ENSO events occurred in 1790–93, 1828, 1876–78, 1891, 1925–26, 1982–83, and 1997–98.
Latest events El Niño occurred in 1986-1987, 1991-1992, 1993, 1994, 1997-1998 and 2002-2003.
The 1997–1998 El Niño in particular was strong and brought international attention to the phenomenon, while what was unusual about the 1990–1994 period was that El Niño occurred very frequently (but mostly weakly).
El Niño in the history of civilization
The mysterious disappearance of the Mayan civilization in Central America could be caused by severe climate changes. This conclusion was reached by a group of researchers from the German National Center for Geosciences, writes the British newspaper The Times.Scientists tried to establish why, at the turn of the 9th and 10th centuries AD, at opposite ends of the earth, the two largest civilizations of that time ceased to exist almost simultaneously. We are talking about the Mayan Indians and the fall of the Chinese Tang Dynasty, which was followed by a period of internecine strife.
Both civilizations were located in monsoon regions, the moisture of which depends on seasonal precipitation. However, at the indicated time, apparently, the rainy season was not able to provide the amount of moisture sufficient for the development Agriculture.
The ensuing drought and subsequent famine led to the decline of these civilizations, researchers believe. They tie climate change With natural phenomenon"El Niño", which refers to temperature fluctuations in 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 The Tang Dynasty died in 907 AD, and the last known Mayan calendar dates back to 903.
