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🌤 | La Nina Phenomenon Ends During Spring El Nino Monitoring Bulletin Highly Likely in Summer

Photo El Nino / La Nina Phenomenon progress and prediction (from the Japan Meteorological Agency website)

La Nina Phenomenon Ends During Spring El Nino Monitoring Bulletin Highly Likely in Summer

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Once the El Nino or La Nina phenomenon occurs, it is thought that abnormal weather will occur all over the world, including Japan.

The Japan Meteorological Agency announced the El Nino monitoring bulletin on Friday, 9th.According to it, the current La Nina, which has been going on since last summer ... → Continue reading

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El Nino-Southern Oscillation

El Nino-Southern OscillationWhat is (El Niño-Southern Oscillation, ENSO, Enso)?atmosphereThen.IndonesiaNear and southThe Pacific OceanAt sea level in the east(I.e.Changes like a seesaw (when the pressure in one is higher than normal, the other tends to be lower),oceanSo in the equatorial PacificSea surface temperature,Ocean currentIt is a general term for natural phenomena on a global scale in which each phase has a duration of several months to several tens of months.

When focusing on the atmosphere,Southern vibrationIf you focus on the ocean,El Nino phenomenon(Or just "El Nino")[1]. The El Nino phenomenon and the Southern Oscillation were initially discussed separately, but as research progressed, it became clear that they were strongly related, and the term "El Nino-Southern Oscillation (ENSO)" was born. ENSO is a representative of the phenomenon in which the atmosphere and the ocean are closely linked (atmospheric-ocean interaction), and it spreads to global weather changes.TeleconnectionIt is also the representative of.

Currently, academically, this series of fluctuation phenomena is called "El Nino-Southern Vibration (ENSO)", and the seawater temperature in the eastern part of the Pacific equatorial region rises at both ends of the fluctuation range.El Nino phenomenonAnd vice versa, the seawater temperature in the eastern Pacific equatorial region drops.La Niña phenomenonThe general idea is that


エ ル ニ ー ニ ョ

El Nino phenomenon(Spanish: El Niño event) Means the central and eastern regionsThe Pacific Ocean OfequatorialIn the vicinitySea water temperatureIs a phenomenon that rises over a year[2].

"El Niño" was originally from South America.ペルーエクアドルEvery year in the waters near the border12It was referring to the phenomenon of rising seawater temperature that occurred around that time.[3]. This is just the time for local fishermenChristmasSince it was aroundSpanishJesus ChristWas called "El Niño"[3]. Usually cold currents in this areaHumboldt CurrentAlthough the seawater temperature is low due to the influence of, it is a warm current during the Christmas season.Equatorial countercurrentThe seawater temperature is rising due to the influence of the southward[4].

After the 1950s, it was found that once every few years, this phenomenon of rising seawater temperature continued after March and affected a wide area of ​​the Pacific Ocean.[3].. This is called the "El Niño event."[4].

The Pacific OceanThen usuallyTrade wind(Eastern wind) is blowingequatorialThe seawater warmed above is drawn to the western Pacific Ocean, but instead cold seawater springs up to the eastern Pacific Ocean.UpwellingTo say[5].. When El Nino occurs, the trade winds that wash away this warm seawater weaken, warm seawater returns to the eastern Pacific, and seawater temperature rises.[6].

When the El Nino phenomenon occurred, the eastern Pacific equatorial regionSea water temperatureIs about 1-2 ° C higher than normal. Sometimes it shows a big rise,1997 - 1998Occurred over20st centuryIn the largest El Nino, the temperature rose by up to 3.6 ° C in the El Nino surveillance area.[7].

The change in seawater temperature that accompanies El Nino first affects the temperature of the atmosphere in that area, which appears as a change in atmospheric pressure, changes the flow of the atmosphere, changes the weather, and so on, and spreads throughout the world. Phenomena that occur in close relation between the atmosphere and the oceanAtmospheric-ocean interaction[8], A phenomenon in which the atmospheric pressure and temperature at a certain point change in cooperation between remote locationsTeleconnectionTo say[9].

Specifically, the seawater temperature "west low east high" causes the temperature "west low east high" and the atmospheric pressure "west high east low".Walker circulationIt changes the conventional atmospheric circulation near the equator. This isRossby wavePropagation,Equatorial equatorial jet stream,Subtropical jet streamDue to changes in the flow path of (Js), it spreads to low latitudes, middle latitudes, and high latitudes in a domino manner, which is peculiar.(I.e.Causes fluctuations. Changes in atmospheric pressure change the flow of the atmosphere in various places with various properties of wet, dry, warm, and cold, and due to unusual atmospheric flow.Abnormal weatherHappens.

Even in mid-latitude Japan, summerrainy seasonIs prolongedCold summer, WinterWest High East Low OfPressure patternIs not stable and tends to be a warm winter.

The process of the El Nino phenomenon

  1. For some reason (wave propagation, westerly burst, etc.), the equatorial current flowing through the Pacific Ocean weakens.
  2. The weakening of the ocean current slows down the speed at which warm water gathers in the western Pacific Ocean, which widens the warm water area in the western Pacific Ocean and spreads it to the central Pacific Ocean.
  3. The rise in seawater temperature lowers the pressure in the central Pacific Ocean, which encourages the strengthening of the west wind burst and eastward travel.
  4. Warm water spreads to the eastern Pacific, which lowers the sea surface temperature in the eastern equatorial region and correspondingly reduces the pressure in the eastern Pacific.
  5. Changes in atmospheric pressure spread around the world, such as the weakening of trade winds toward the western Pacific Ocean, causing abnormal weather.
  6. For some reason (propagation of equatorial waves, north-south movement of warm water, etc.), the equatorial current flowing through the Pacific Ocean strengthens, and the seawater temperature returns to normal.
  7. Changes in atmospheric pressure that have become normal will spread all over the world, and abnormal weather will subside.

La Niña

La Niña phenomenon(Spanish: La niña) Is a phenomenon in which the seawater temperature drops near the equator in the eastern Pacific Ocean, contrary to the El Nino phenomenon.

La Nina means "girl" in Spanish[10].. It was sometimes called "Anti-El Niño" because it was the opposite of "El Niño", but "AntichristBecause of the meaning of "", it came to be called "girl (La Niña)" in opposition to boys.

Even in normal years, the eastern Pacific equatorial region has a lower seawater temperature than the western Pacific Ocean and the Atlantic Ocean in the same equatorial region. Cold seawater in the eastern Pacific equatorial region during La NinaUpwellingBecomes stronger and the water temperature drops,Thermo KleinThe shallow cold water (water thermocline) extends westward along the equator, and the temperature difference between east and west becomes even larger.

Like El Nino, it spreads all over the world and causes extreme weather. Due to its nature, it may cause abnormal weather that is the exact opposite of El Nino. For example, in Amazon, where there is heavy rainfall in El Niño, there is light rain and drought in La Niña. This is noticeable in the equatorial Pacific Ocean, where it occurs, but it is often not the case in other regions. In some cases, it occurs in reaction to the end of El Nino.

Although El Niño and La Niña have a side-to-side relationship, there are some differences. that is,

  • Due to the mechanical mechanism, the decrease in seawater temperature due to La Niña is not as strong as the increase in seawater temperature due to El Niño.
  • La Nina often appears the year after El Nino, while La Nina often lasts for a long time (2-3 years).

General remarks

The El Nino phenomenon and the La Nina phenomenon are closely related to each other, like the front and back of a coin, and cannot be considered separately. As research into changes in seawater temperature and pressure in this area progresses, El Nino and La Nina are the ocean and atmosphere.InteractionIt was revealed that it will be caused by. Interaction is a kind of interlocking called El Nino-Southern Vibration (ENSO) in the atmosphere and ocean near the equator of the Pacific Ocean.システムEl Nino and La Nina are considered to be phenomena that occur in this constantly changing system.

Looking at the cases of El Nino and La Nina, they occur about every four years in recent years, and once they occur, they last for one to one and a half years. El Nino and La Nina often alternate. However, it may occur at intervals, or it may occur more than once in a row. As a mechanism that occurs alternately1980 eraAfter the latter half, some hypotheses such as delayed-action oscillator theory have been proposed and verified by observation data analysis.

There is no universal definition of the El Nino-La Nina phenomenon, and there are multiple definitions set by each meteorological organization. Among them, the definitions of the Japan Meteorological Agency and the US National Oceanic and Atmospheric Administration are widely used academically by researchers in each country.

By the way, the normal state where El Nino and La Nina do not occur is sometimes expressed as La Nada, a Spanish word meaning "nothing". However, it is rarely used in Spanish-speaking countries and is not often heard in Japan.

El Nino-La Nina is a major source of disruption in long-range forecasts of weather weeks and months ahead. It is said that this forecast is indispensable for improving the accuracy of forecasts, because it causes a big disappointment such as a cold summer despite the forecast of intense heat.

Root cause of outbreak

Research is being conducted to determine the root cause of abnormal seawater temperature and pressure, but the root cause has not yet been elucidated in detail. However, some have been elucidated.

First, in the case of El Nino, the Equatorial Current (which flows from east to west several months before the seawater temperature anomaly occurs (North Equatorial CurrentSouth Equatorial Current) Has been observed to weaken or reverse. It is believed that this is due to a change in the ocean current for some reason. In addition, after the reversal, a phenomenon () in which the westerly wind suddenly strengthens has been observed in low latitude regions of the western Pacific Ocean (near the Philippines, etc.), but this is because the seawater temperature changes due to changes in the Equatorial Current, which is transmitted to the atmosphere. It is thought to occur in the process of causing fluctuations in atmospheric pressure. However, it cannot be concluded which is the cause and which is the result of the Equatorial Current or the westerly current burst. This is because they are closely related to each other in the ocean-atmosphere interaction phenomenon, and it is very difficult to elucidate them.

Also, according to a recent study, the moonTidal forceIt has been pointed out that it may be related to the change in[11].. This is the tidal force of the moonHot salt circulationIt is said that it may also affect[12][13][14].. There is a movement to investigate the cause by reproducing ENSO and the accompanying weather changes with high accuracy in models, etc., but in any case, the root cause has not been determined.

On the other hand,Global warmingThere is a great deal of scientific and social interest in the relationship between El Nino and La Nina.Climate modelbyIPCCForecast,Japanese Meteorological Agency[15]In all of the forecasts of each research institute, including the above, there are many predictions that the seawater temperature in the eastern part of the Pacific equatorial region will rise slightly on average, and that seawater temperature anomalies such as El Nino will intensify. There are also many general perceptions that global warming will increase or strengthen El Nino. However, even if the climate model predicts that "El Nino will strengthen / increase", it has not reached a certain level that can be concluded as "strengthening / increasing". The cause of El Nino is not clearly understood, there are still small-scale weather that the model cannot reproduce (due to low resolution), and the model is not yet reproducible for phenomena such as El Nino. It is listed as the cause. Researchers are also divided into the opinion that the trend of changes in seawater temperature in the eastern Pacific equatorial region over the past few decades is related to global warming and that it is a natural change.[16].. In conclusion, at this stage, it cannot be concluded that "El Nino will be strengthened / increased" based on the model's predictions, and the relationship with global warming is only "possibly related".

There is an idea that "El Nino is caused by global warming", but it is speculative.

Past El Nino / La Nina

periodEl / LaExample of abnormal weather
1949summer - 1950Summer: La Niña 
1951Spring --1951 /1952Winter:エ ル ニ ー ニ ョ
1953Spring --1953 /1954Winter:
Spring 1954- 1955/1956Winter:La NiñaThe La Nina phenomenon has occurred, but summer is a cold summer. 1955 is a hot summer in the 50s. However, in autumnCold autumn.. 1956 is a cold summer nationwide. Autumn is cold autumn.
1957Spring 1958Spring:エ ル ニ ー ニ ョ 
1962Winter- 1963Spring:La NiñaHeavy cold waves in East Asia, including North America, Europe, and Japan (including heavy snowfall in Japan)Showa 38 heavy snow))
Summer 1963-1963 /1964Winter:エ ル ニ ー ニ ョ 
Spring 1964 ―― 1964 /1965Winter:La Niña
Spring 1965 ―― 1965 /1966Winter:エ ル ニ ー ニ ョ
1967autumn - 1968Spring:La Niña
Fall 1968- 1969/1970Winter:エ ル ニ ー ニ ョ
Spring 1970- 1971/1972Winter:La Niña
Spring 1972- 1973Spring:エ ル ニ ー ニ ョ
Summer 1973- 1974Spring:La Niña
1975Spring 1976Spring:
Summer 1976- 1977Spring:エ ル ニ ー ニ ョSummer is a very cold summer, but winter is a very cold winter
Sleet observed in Okinawa Prefecture in February 1977
Summer 1977- 1978Fall:La Niña1977 is a cold summer in Japan. 1978 is a hot and cold winter
Winter 1978- 1979Summer: エ ル ニ ー ニ ョWarm winter / cold summer or average summer in Japan.
Fall 1979- 1981/1982Winter:La NiñaCold winter in Japan, cold spring, cold summer, cold autumn in 1981
Spring 1982- 1983Summer: エ ル ニ ー ニ ョ Warm spring in spring and cold summer in summer (excluding August).
Fall 1983- 1984Spring:La NiñaCold winter and cold spring in Japan (this cold lasted until early May 1984)
Summer 1984- 1985Fall: 
1986autumn - 1987/1988Winter:エ ル ニ ー ニ ョ
Spring 1988- 1989Spring:La Niña
1991Spring 1992Summer: エ ル ニ ー ニ ョWarm winter / hot summer in Japan (1991) However, 1992 is a warm winter / cold summer
1993Summer --1993 /1994Winter:Great in JapanCold summer(At this time, JapanRice cultivationIn most areasBad cropBecame (1993 US uproar)) ・ Warm winter
Summer 1994- 1996Winter:La NiñaIn 1994, it was the highest ever in Japan, the hottest heat in the history of observation, warm autumn, and 1 was the cold winter and cold spring except Hokkaido.
1997Spring 1998Spring:エ ル ニ ー ニ ョAmami Okinawa has a very warm winter, a warm winter in eastern and western Japan, a cold winter in Hokkaido, a flood in eastern Europe, heavy rain in North America, light rain in Southeast Asia, and high temperatures all over the world.
Summer 1998- 2000Spring:La NiñaExtreme heat and warm autumn in eastern Japan-northern Japan in 1999, drought in China, heavy rain in Indonesia, cold wave in Europe
2002Summer --2002 /2003Winter:エ ル ニ ー ニ ョHeavy rains in east, Southeast Asia and Europe, low temperatures in India, droughts in India and eastern Australia, impact on Japan is limited to northern Japan and high temperatures in western Japan
2005autumn - 2006Spring:La NiñaLight rain in Pakistan, India and Mongolia, low temperature and cold waves in Europe and East Asia, heavy rain in North America, heavy cold wave in Japan (excluding the latter half of February), heavy snowfall (excluding the latter half of February)18 heavy snowfall
Summer 2006- 2007Spring:エ ル ニ ー ニ ョDrought in Australia (more than 5 ° C above NINO.3 standard value for 0.5 months) Flood in Bolivia, Peru and East Africa, warm winter in Japan along with 1949
Summer 2007- 2008Spring:La NiñaExtremely hot, warm autumn, cold waves mainly in August on the Japan Sea side of western Japan to northern Japan, drought in North America, heavy snowfall in China, cold wave in Europe
2009Summer-autumnエ ル ニ ー ニ ョHeavy rainfall throughout Asia, long-term heavy rainfall in western Japan (July 21 Heavy rain in northern China and Kyushu,21 Typhoon No. 8,21 Typhoon No. 9), 2000s record cold summer, September and cold autumn in northern Japan
Winter 2009- 2010Spring:Record-breaking cold waves in Europe, North America, China, South Korea, and India. In Japan, the national average temperature was higher than normal and the Japan Meteorological Agency announced that it was a warm winter, but a temporary strong cold wave on the Sea of ​​Japan side of western Japan and northern Japan.・ There was a large temperature difference between heavy snowfall and eastern Japan to northern Japan, such as cold spring. on the other handWinter OlympicsWas heldVancouverThen.Cherry blossomWas in bloom.
2010summer - 2011Fall: La NiñaThe hottest heat in the history of observation in Japan in the 21st century, centered on SeptemberWarm autumn.heatstrokeMany deaths due to
2012Summer-winter エ ル ニ ー ニ ョExtreme heat and warm autumn centered on the Sea of ​​Japan side of western Japan to northern Japan However, June is a cold summer, July is normal and August is extremely hot (warm autumn excludes western Japan and Amami Okinawa)
2013Spring-autumnLa NiñaLarge-scale cold spring since 1996, torrential rain in summer mainly in western Japan (all over Japan except Okinawa)Heavy rain in Shimane and Yamaguchi prefecture on July 25, 7Such)
2014Summer-winter Warm autumn centered on October on the Sea of ​​Japan side of western Japan to northern Japan, and December-next year (2015) Cold waves and long-term snowfall mainly until early February
Long-term heavy rain in Sri Lanka
2015summer - 2016Spring: エ ル ニ ー ニ ョExcept for northern Japan, it was a cold summer only in June, and a record heat wave from the latter half of July to the first half of August. However, the latter half of August was a cold summer. Long-term heavy rainfall mainly in August-September in Hokkaido and eastern Japan to western Japan (eg)September 27 heavy rain in the Kanto and Tohoku regions(Mainly Tochigi prefecture, Ibaraki prefecture, Miyagi prefecture), etc.) In northern Japan excluding Hokkaido, the first snow and the first snowfall were observed 10 days to 14 days later than normal, and in Okinawa, a long-term summer day was observed in December.
December is not only in Japan but also in many foreign countriesNorthern hemisphereIt was the largest warm winter. However, in January 2016, a big cold wave struck mainly in western Japan, snowfall in Amami Oshima in Kagoshima prefecture for the first time in 1 years since 1901, and sleet in Okinawa prefecture for the first time in 115 years since February 1977. After observing each, a large cold wave struck in North America, East Asia, and Europe.
Summer 2016- 2017Spring:La NiñaLong-term heavy and heavy rains in August, mainly in Hokkaido
1951ToJapanese Meteorological AgencyTyphoon landed on the Pacific side of the Tohoku region for the first time since the company began collecting statistics (28 Typhoon No. 10).
In northern Japan, the first snow and the first snow were observed 7-10 days earlier than normal, and the first snow and the first snow were observed in Kanto Koshinetsu in November 2016 (The first snow and the first snow were observed in November in Kanto Koshinetsu. This is the first time in 11 years since November 11).
In addition, in mid-January, mid-February, and early March 2017, the largest cold wave in the Northern Hemisphere struck not only in Japan () but also in many foreign countries once every 1 years.
Fall 2017- 2018Spring:30 heavy snowfallSee

The average temperature this winter (December 2017-February 12) was about 2018 degree lower.

And the amount of snow in winter was much higher than normal, and it became a cold winter on a Japanese scale.

Fall 2018- 2020Spring:エ ル ニ ー ニ ョ30 Typhoon No. 21See

(September 2018) On September 9, a typhoon approached the Kinki region and became a dangerous storm.

From September 9th to September 7th, the autumn rain front approached, and there was intermittent rain in western Japan.

Winters were almost nationwide, with record warm winters in the Nansei Islands, remarkable warm winters in western and eastern Japan, and record light snow on the Sea of ​​Japan side of western Japan.

From May to July 2019, there were record long-term high temperatures, long-term sunshine, and long-term light rain, mainly in northern Japan.

Until mid-July, it tended to be a cold summer, but August 7 was a normal or higher summer.

In June 2019, a large amount of hail fell locally in South America, and abnormal weather such as long-term abnormally high temperature occurred in Europe.

From December 2019 to February 12, except for northern Japan, December 2020-February 2 was a record warm winter.

Fall 2020- 2021Spring:La NiñaReiwa 3rd year heavy snowfallSee

From early winter of 2020, the largest cold wave hits once every few years, mainly in Japan (excluding Amami Okinawa), and the total snowfall for 1 days from December 12 to 14 is 21 cm (excluding Amami Okinawa). We observed record heavy snowfalls at several points beyond 7 meters), mainly on the Sea of ​​Japan side of eastern and northern Japan, and mainly in the San'in region and Nagasaki in northern Kyushu.[17].

Especially from January to mid-February 2021, in Japan, mainly on the Sea of ​​Japan side of northern Japan and western Japan, it was a record-breaking winter that surpassed that of January-February 1 (although the latter half of February was a mild winter. It was a trend).

In early January 2021, not only Japan but also East Asia such as China and South Korea, some North America, and Europe were hit by the largest cold wave once every few years, especially.スペインThe capital ofMadridThen it was the first heavy snowfall in half a century (50 years)[18].

* Seasons are classified according to the "Northern Hemisphere Seasons" defined by the Japan Meteorological Agency (Spring: March-May, Summer: June-August, Autumn: September-November, Winter: December-February).
* The standard for the presence or absence of occurrence is latitude and longitude 1 degree square accuracy.1891The monthly average seawater temperature (SST) of the target month is used as the basic data, and the monthly average seawater temperature for 30 years up to the previous year of the target month is used as the "reference value" in the NINO.3 (described later) sea area. 5 monthsmoving averageWhen the values ​​are compared and the value exceeds the reference value by 0.5°C or more for 6 months or more, it is indicated as “El Niño”, and the state in which the value is 0.5°C or more and less than the reference value continues for 6 months or more is indicated as “La Niña” (the period isTaiziThings).

There are some cases where the seawater temperature rises and falls even when the definition is not met, and abnormal weather such as El Niño La Niña occurs (those with normal letters).

Old age El Nino

(Dr. Groub, Australian National University, 1998, Nature)

  • 1396
  • 1685-1688
  • 1789-1793
  • 1877-1879

Typical weather at the time of El Nino / La Nina

During the outbreaks of El Nino and La Nina, weather trends are different from normal times around the world. However, as mentioned aboveHigh correlation between ENSO and weather in the Pacific OceanBut,Other factors have a large impact in other regionsTherefore, it is not always as follows. In JapanTemperature rise in the entire Indian Ocean-Dipole mode phenomenon(IOD) etc.Indian OceanAbnormal sea temperatureArctic oscillationIn addition to being strongly influenced by (AO), AO andNorth Atlantic OscillationSince it is strongly affected by (NAO), it is necessary to make a comprehensive judgment when considering the weather trends, so care must be taken. Weather patterns are being elucidated and climate models are being improved in order to predict changes in the weather that change due to these complex factors.

Note that the following list of “typical weather in the world” is only a selection of statistical trends, and includes those for which the causal relationship with ENSO is not clear, such as the mechanism being not fully understood.

エ ル ニ ー ニ ョ

El Nino by Western Pacific Equatorial (フィリピン-Indonesia-MicronesiaWhen the seawater temperature in (near) decreases, convection activity in the same area becomes weaker than usual.

Every summerrainy seasonからautumn rainBring clear weather to JapanPacific high, The updraft mainly from the equatorial region of the western Pacific Ocean descends via the upper troposphereHadley circulationKeeps power by. Also,Pacific-Japanese patternCalled (PJ)TeleconnectionDepending on the pattern, the high and low atmospheric pressure around JapanフィリピンThere is an interlocking effect that it is opposite to the high and low of the atmospheric pressure in the vicinity. Therefore, when convective activity becomes inactive, the Hadley circulation in the region weakens, and the weakening of the Pacific high pressure to the west weakens. The pressure drops. Therefore, the inflow of (warm and moist air) from the southwestOkhotsk Sea HighOverhang (coolNortheast airflowInflux) has become stronger, and there is a tendency for Japan to become a cold summer with lots of cloudy weather and rain.[19][20]

In winterSiberian high pressureWhile progressing cyclically, proceed east of JapanTemperate lowBoth ofWest High East Low OfPressure patternMakeSea of ​​Japan sideOn snow,Pacific Ocean sideBring a dry sunny to. At El Niño,Pacific/North American patternBy (PNA)Aleutian LowWill increase in power,Arctic oscillationbychillSouth ofAleutian IslandsIt is fixed in the vicinity and it becomes difficult for cold air to enter around Japan, while (WP)Mainland ChinaからMidway islandIn the mid-latitude northwestern Pacific, the atmospheric pressure increases, the west high east low weakens, and the cold northwest monsoon weakens.In Japan, it tends to be warm and sunny in the Sea of ​​Japan side. There is.[19][20]

La Niña

Western Pacific Equatorial Region by La Nina (フィリピン-Indonesia-MicronesiaWhen the seawater temperature in the vicinity) rises, convective activity becomes stronger than usual in the same area.

In the summerPhilippine SeaThe pressure decreases due to the increased convective activity in the eastern Philippine waters, whilePacific-Japanese pattern(PJ) to the east of JapanPacific highBecause it strengthens its power and makes it easier to project to the north,Northern JapanWhile it is sunny and the temperature tends to be high, the inflow of (warm and moist airflow) becomes stronger due to the direct influence of the activation of convective activity.Nansei IslandsIt tends to rain a lot.[19][20][22]

In winter,Siberian high pressureWhile strengtheningAleutian LowDeveloped more westward than usual (in the sea near eastern Japan)West High East LowThe pressure distribution in the area has become stronger, and the cold northwest monsoon has also become stronger.West JapanThe temperature tends to be low, especially in.[19][20]

El Nino-Southern Vibration Monitoring and Prediction

Currently, research institutes and public meteorological institutions are monitoring indicators such as seawater temperature and atmospheric pressure based on data from marine observations and satellite observations. Some arewebIt is also published above.

El Nino surveillance area

The World Meteorological Organization has set up five sea areas for El Nino monitoring and is collecting statistics on their seawater temperature trends.

  • NINO.4 sea area The Pacific OceanWestern waters (5 ° N-5 ° S, 160 ° E-150 ° W)
  • NINO.3 Sea Area East Pacific Ocean Area (5 ° N-5 ° S, 150 ° W-90 ° W) --The Japan Meteorological Agency has designated it as an El Nino monitoring area. The reference value is described above.
  • NINO.1 + 2 sea area ペルーOffshore (0 ° -10 ° S, 90 ° W-80 ° W)
  • NINO.WEST sea area IndonesiaNorthern waters (15 ° N-0 °, 130 ° E-150 ° E)

Southern vibration index

SOI (Southern Oscillation Index). On the South PacificTahitiAustraliaThe city ofDarwinAn index of the atmospheric pressure difference with. It is used as a value to indicate the level of southern vibration. When El Nino occurs, it tends to show a minus.


  • --Trade winds in the Pacific equatorial region,Walker circulationAn index that represents the strength of. There is also a reciprocal relationship between the upper and lower layers, where the upper layer is weak when the circulation in the lower troposphere is strong.
  • Ocean heat storage --Shows changes in sync with El Nino La Nina.It may appear prior to occurrence / convergence, but its correlation is lower than that of MJO.Pacific / Indian Ocean Equatorial Region 0-300m The change tendency is calculated from the longitude-time cross section of the normal deviation of water temperature.
  • --Indicates the activity of convective activity.At El Nino, it becomes active in the eastern part of the Pacific equatorial region and calms down in the western part.
  • IOBW Sea surface temperature in the Indian Ocean tropical zone (20 ° N-20 ° S, 40 ° -100 ° E) --NINO.3 The water temperature in the sea area shows similar changes with a delay of about one month. In the case of El NinoTemperature rise in the entire Indian OceanIt is an important monitoring target because it may cause.
  • Madden Julianian vibration(MJO) --It is thought to be closely related to the occurrence and convergence of El Nino and La Nina. The change tendency is determined from the longitude-time cross-section of the velocity potential normal deviation in the upper troposphere and the longitude-time cross-section of the east-west wind speed normal deviation in the lower troposphere.

Discovery of El Nino Southern Vibration (ENSO)

British mathematical physicist appointed Secretary of the Indian Meteorological Department in 1903Gilbert WalkerUsing long-term meteorological data from around the world, which has just begun to be developed, and his favorite statistics, he undertook a study to "search for signs of the Indian monsoon using the spatiotemporal correlation between meteorological elements."[23]..彼はスタッフを総動員して膨大なデータ同士の相関計算に取り組み、その相関関係から1928年に発表した3つの大気振動の一つが「南方振動(Southern Oscillation: SO)」だったHe mobilized all the staff to work on the correlation calculation between huge amounts of data, and from that correlation, one of the three atmospheric vibrations announced in XNUMX was "Southern Oscillation (SO)".[23]..By the way, the remaining two are "North Pacific Oscillation" and "North Atlantic Oscillation".一方で、1925~1926年に強いエルニーニョが起こった際に、たまたま研究のためにペルーを訪れていたアメリカの鳥類学者で自然保護主義者だったOn the other hand, he was an American ornithologist and conservationist who happened to be visiting Peru for research during the strong El Nino of XNUMX-XNUMX.Robert MurphyEstablished a climate observation network in South America to investigate this effect widely and began meteorological observation.[24] .

Initially, the southern vibrations of the atmosphere and El Nino in the ocean were thought to be independent phenomena of the atmosphere and the ocean, respectively.ところがこの両者が関連していることを明らかにしたのが、インドネシアのジャカルタにあるオランダ東インド王立磁気気象観測所に勤めていた気象学者ヘンドリック・However, it was revealed that the two are related by meteorologist Hendrick, who worked at the Royal Magnetic Meteorological Observatory in East India in the Netherlands in Jakarta, Indonesia.Berlage Jr.Is[25]..The observatory is conducting research on southern vibrations, and Berlahe obtained the results of Murphy's weather observations in western South America presented at the 1926rd Pacific Conference held in Tokyo in 3.彼はこの二つの結果を突き合わせて、大気現象の南方振動と海洋現象のエルニーニョに高い相関があることを発見し、1957年に初めて両者が関連していることを発表したHe combined these two results and discovered that there was a high correlation between the southern vibrations of atmospheric phenomena and the marine phenomenon El Nino, and in XNUMX first announced that they were related. [26]..これがENSOの発見とされているThis is said to be the discovery of ENSO[25].

It was a professor at UCLA in the United States who elucidated this mechanism.Jacob BeyaknessIs. HeInternational Geophysical YearAnalyzing observed ocean data such as (IGY), it is said that the abnormal rise in sea level off Peru during El Nino occurs when the cold equatorial upwelling from the deep ocean off Peru stops as the trade winds weaken. Announced the mechanism.In 1969, Jacob Beyakness called the east-west atmospheric circulation in this tropical zone the "Walker circulation" because the east-west circulation of the atmosphere due to the east-west gradient of sea surface temperature was the main mechanism of the southward vibration shown by Walker. I named it.

Similar phenomenon

El Nino Modoki

Tokyo University OfToshio YamagataIs a phenomenon named byThe Pacific OceanBy raising the seawater temperature in the central partUpdraftBy the occurrence ofPacific highBecome stronger[27][28].2004Occurred in Japan in the summerIntense heat,Torrential rainIs believed to be the cause of.

Atlantic Nino

It is a phenomenon that occurs once every few years, and the water temperature deviation is not as large as the El Nino phenomenon. However, it has a large impact on the climate of South America and Africa in the surrounding area, causing floods and droughts in the tropical regions, and it has been suggested that it also affects El Nino. Similar to the El Nino phenomenon, the mechanism of occurrence is the type that "once every few years, the warm water in the west protrudes to the east due to the influence of the weakened trade wind" and "the water temperature in the ocean surface on the north side of the equator is higher than usual. Warmed and warmed seawater is transported to the equatorial region[29]Is believed to be.

Dipole mode phenomenon

Indian OceanSo, the phenomenon that the seawater temperature and atmospheric pressure in the eastern part of the equator and the western part of the equator change in opposition.[30].. It may be linked to ENSO, but it may also occur independently. Affects the weather in Africa, Monsoon Asia and Oceania.

California Nino / Nina Phenomenon

CaliforniaからBaja California PeninsulaIn this sea area, the surface seawater is blown offshore by the influence of the sea wind and the rotation of the earth, and cold water springs out from the lower layer to supplement the washed seawater. That is, when the sea wind in this sea area becomes strong, the sea water temperature decreases, and when the sea wind becomes weak, the sea water temperature rises. Therefore, although the surface seawater temperature in this sea area is kept low, a phenomenon in which the secular fluctuation of the sea surface temperature in the coastal area is deviated due to long-term fluctuations in the strength of the sea wind. It was named by researchers of the Japan Agency for Marine-Earth Science and Technology (Kasumi Goushio, Toshio Yamagata).

Previously, it was thought to be a phenomenon caused by the El Niño / La Niño phenomenon, but research by the Ocean Research and Development Organization revealed that it is an atmospheric-ocean coupling phenomenon independent of the El Niño / La Niño phenomenon. Became[31].


AmericanColumbia UniversityAccording to a report by the Research Institute for Humanity and Nature, there is a correlation between El Nino, which causes temperature rise and rainfall decrease, and the periodic increase in war every three to seven years.[32]。報告によれば、1950年から2004年までのエルニーニョ南方振動について、175カ国で1年間に25人以上の死者を出した234の内紛(半数以上が1,000人以上の戦死者を出したもの)の発生との相互関係を調査した結果、ENSOの影響を受けた国における内乱の発生する率はラニーニャ発生期間に約3%、エルニーニョ発生期間にはその倍の6%と倍だったものの、ENSOの影響を受けなかった国では、常に2%のままで、エルニーニョは世界中の21%の内紛でその一因となった可能性があり、エルニーニョの影響を受けた国々ではその割合が30%になるとされる[32].

Poor countries are more prone to turmoil due to bad weather, and rich Australia depends on ENSO, but there has been no internal conflict so far, but in the highlands of Peru and southern Sudan, internal conflict has intensified since the year of El Nino. It is said that it has developed into a long term[32][33].


[How to use footnotes]
  1. ^ Ogura 2016, pp. 284-285.
  2. ^ Ueda 2012, p. 25.
  3. ^ a b c Ogura 2016, p. 282.
  4. ^ a b Nishina 2014, p. 121.
  5. ^ Sakaida 2008, p. 71.
  6. ^ Nishina 2014, pp. 122-123.
  7. ^ Ogura 2016, p. 283.
  8. ^ Ueda / Tanaka 2007, p. 26.
  9. ^ Yoshimitsu Ogura, 1984, "General Meteorology", University of Tokyo Press ISBN 4-13-062084-3
  10. ^ En Takayabu, Masaki Kawabe, Takashi Nakamura, Toshio Yamagata, Shinzo Fujio, "All about the Sea," Newton Press, 2017, p. 95.ISBN 978-4-315-52060-6. 
  12. ^ Nature, 2000, 405 (6788) 775[2]
  13. ^ Science, 2002, 298, no.5596, 1179[3]
  14. ^ Journal of Marine Research, 64, 797, 2006[4]
  15. ^ Climate Change Prediction Information Volume 5 HTML Version, Japan Meteorological Agency.
  16. ^ Q & A about the El Nino phenomenon Is there a relationship between the El Nino phenomenon and global warming?, JMA,2007May 7Browse.
  17. ^ December 2020 Summary of heavy snowfall so far Total snowfall exceeds 12 cm (tenki.jp) - Yahoo! News April 2020, 12 (Viewed April 21, 2021)
  18. ^ Spanish capital, heavy snow for the first time in 50 years - Jiji Press January 2021, 1 (viewed on the same day)
  19. ^ a b c d "Characteristics of the weather associated with the El Nino / La Nina phenomenon"Japan 1, Japan 2 Japan 3 Summary of the Japan Meteorological Agency, based on observation data from 1979 to 2008. Seasonal classification is from the Japan Meteorological Agency (Spring: March-May, Summer: June-August, Autumn: September-November, Winter: December-February).
  20. ^ a b c d Marine Health Examination Table "Comprehensive Diagnosis Table" 2.3 El Nino Phenomenon Japan Meteorological Agency.
  21. ^ a b "Characteristics of the weather associated with the El Nino / La Nina phenomenon" World 1, World 2 Summary of the Japan Meteorological Agency, based on observation data from March 1979 to February 3. Seasonal classification is from the Japan Meteorological Agency (Spring: March-May, Summer: June-August, Autumn: September-November, Winter: December-February).
  22. ^ Extreme Weather Report 2005 1.5.3 El Nino / La Nina Phenomenon and World Weather and Typhoon Activity Japanese Meteorological Agency
  23. ^ a b Cox, John D. (2013.12). Scientists in the true identity of the stormTranslated by Nochi Tsutsumi. Tokyo: Maruzen Publishing. ISBN 978-4-621-08749-7. OCLC 869900922. https://www.maruzen-publishing.co.jp/item/b294698.html 
  24. ^ Cushman, Gregory T. (2004). “Enclave Vision: Foreign networks in Peru and the internationalization of El Nino research during the 1920s”. Proceedings of the International Commission on History of Meteorology 1. 
  25. ^ a b Satoshi Tsutsumi. (2018). Development history of meteorology and weather forecastingMaruzen Publishing. ISBN 978-4-621-30335-1. OCLC 1061226259. https://www.maruzen-publishing.co.jp/item/b302957.html 
  26. ^ Enfield, David B. (1989). “El Niño, past and present”. Reviews of Geophysics 27 (1): 159. two:10.1029 / rg027i001p00159. ISSN 8755-1209. https://doi.org/10.1029/rg027i001p00159. 
  27. ^ Low-latitude Climate Prediction Research Japan Agency for Marine-Earth Science and Technology JAMSTEC
  28. ^ El Nino Modoki (PDF)
  29. ^ New climate change mechanism in the Atlantic equatorial regionJapan Agency for Marine-Earth Science and Technology JAMSTEC
  30. ^ Indian Ocean Dipole Japan Agency for Marine-Earth Science and Technology JAMSTEC
  31. ^ Discovered the California Niño / Niña phenomenon for the first time in the world Japan Agency for Marine-Earth Science and Technology JAMSTEC April 2014, 4
  32. ^ a b c "Research Report: Climate Cycle Drives War". 2017th of February 2Browse.
  33. ^ "Climate Cycles Are Driving Wars, Says Study". 2017th of February 2Browse.


  • Hiroaki Ueda, Hiroaki Tanaka "Ocean" "Global Environmental Studies-30 Chapters for Investigating, Analyzing, and Diagnosing the Global Environment-" Norikazu Matsuoka, Hiroshi Tanaka, Michiaki Sugita, Yuji Murayama, Akira Tezuka, Yuichi Onda (ed.), Kokon Shoin, 2007, pp. 25-28.ISBN 978-4-7722-5203-4.
  • Kiyotaka Sakaida, "Climate Change and Change," "Introduction to Natural Geography," Hideo Takahashi and Takeei Koizumi (eds.), Asakura Shoten, 2008, pp. 64-74.ISBN 978-4-254-16817-4.
  • Hiroaki Ueda, "Climate System Theory," University of Tsukuba Press, 2012.ISBN 978-4-904074-21-3.
  • Junji Nishina "Easy Climate Studies" Kokon Shoin, 2014, 3rd edition.ISBN 978-4-7722-8506-3.
  • Yoshimitsu Ogura"General Meteorology" University of Tokyo Press, 2016, 2nd edition, revised edition.ISBN 978-4-13-062725-2.
  • Tsutsumi Notomo "Development History of Meteorology and Meteorological Forecast" Maruzen Publishing Co., Ltd., 2018, Discovery of El Nino and Southern Vibration,ISBN 978-4-621-30335-1.

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