What is the Manina phenomenon?

La Nina is the Spanish word "La Nina" - "little girl, saint". It is the opposite phase of El Niño. It refers to a phenomenon in which the water temperature in the eastern Pacific near the equator drops abnormally, manifesting as a phenomenon in the eastern Pacific. Significant cooling, accompanied by global climate disruption, always follows an El Niño event

A term used by meteorologists and oceanographers to refer specifically to the widespread, abnormal cooling of ocean waters that occurs in the eastern and central equatorial Pacific. phenomenon (sea surface temperature is more than 0.5℃ lower than the climatic average, and lasts for more than 6 months). La Niña is also called the anti-El Niño phenomenon.

Generally, the La Niña phenomenon will follow the El Niño phenomenon. The La Niña phenomenon will occur in the second year after the El Niño phenomenon occurs. Sometimes the La Niña phenomenon will last for two or three years, and strong La Niña phenomena occurred from 1988 to 1989 and 2001, which caused the sea water temperature in the eastern to central Pacific Ocean to rise. It is 1 to 2 degrees Celsius lower than normal, and the La Niña phenomenon that occurred in 1995 and 1996 was weaker. Some scientists believe that the La Niña phenomenon is weakening due to the trend of global warming.

The La Niña phenomenon appeared in 1998 and lasted until the spring of 2000. El Niño and La Niña phenomena usually occur alternately and have roughly opposite effects on climate. They affect climate change by changing the atmospheric circulation through the energy exchange between the ocean and the atmosphere. According to the monitoring data of the past 50 years, El Niño occurs more frequently than La Niña and is more intense than La Niña.

La Niña often occurs after El Niño, but this does not happen every time. Four years.

Chinese oceanographers believe that the devastating floods China suffered in 1998 were caused by two major causes: the "El Niño-La Niña phenomenon" and the ecological deterioration of the Yangtze River Basin. .

Chinese oceanographers and meteorologists have noticed that last year’s El Niño (warming of the ocean) in the tropical Pacific has transformed into a La Niña (cooling of the sea) within a month. This unprecedented situation is one of the reasons for the sudden increase in rainfall in the Yangtze River Basin.

This time El Niño also caused China's climate to be very abnormal. From June to July 1998, there were frequent rainfalls in Jiangnan and South China. Severe floods have occurred in the Yangtze River Basin and the two lake basins. The water levels of some rivers have exceeded warning levels for a long time. Rainfall in parts of Guangdong, Guangxi and Yunnan has been over 50%. La Niña has also caused climate anomalies in some areas of North China and Northeast China. Chao Jiping, academician of the Chinese Academy of Sciences and honorary director of the National Marine Environment Forecasting Research Center, said that the current situation is: the influence of El Niño has not completely disappeared, and the influence of La Niña has begun again, which makes China's climate status generally become extremely complicated. It is said that after the large-scale warm and humid air caused by El Niño moves to higher latitudes in the northern hemisphere, it encounters cold air from the north, causing an exchange of cold and warm air, resulting in increased rainfall. But after June, summer arrives, the rain belt moves northward, and the flood season in the Yangtze River Basin should end. But at this time La Niña appeared, the air in the south became colder and sank, and the warm and humid flow that had moved northward retreated to fill the vacuum. In fact, the subtropical high pressure reached 30 degrees north latitude on July 10, and then suddenly retreated south to 18 degrees north latitude. This phenomenon has never been seen in history.

La Niña" is an overcorrection phenomenon after an El Niño year. This hydrological feature will cause the water temperature in the eastern Pacific to drop and drought to occur. On the contrary, the water temperature in the west will rise and the precipitation will be significantly biased compared to normal years. Scientists believe that the hydrological phenomenon of "La Niña" will not have a major impact on the world's climate, but it will bring more rainfall to Guangdong, Fujian, Zhejiang and even the entire southeastern coast.

< p>El Niño, also known as El Niño current, is a climate phenomenon caused by the loss of balance between the ocean and the atmosphere in the large-scale equatorial zone of the Pacific Ocean. Under normal circumstances, the monsoon ocean currents in the tropical Pacific region move from the Americas to Asia, causing the Pacific Ocean to move. The surface remains warm, bringing tropical rainfall around Indonesia, but this pattern is disrupted every 2 to 7 years, causing the wind direction and ocean currents to reverse, and the heat flow on the Pacific surface turns east toward the Americas, taking it away with it. The so-called "El Niño phenomenon" occurs due to tropical rainfall.

The word "El Niño" comes from Spanish, and its original meaning is "Holy Infant", in Spanish-speaking countries such as Ecuador and Peru in South America. In this country, fishermen have discovered that every few years, from October to March of the following year, there will be a warm current moving south along the coast, causing the surface seawater temperature to increase significantly on the Pacific east coast of South America. What is happening is the Peruvian cold current. The fish that move with the cold current make the Peruvian fishing grounds one of the three largest fishing grounds in the world. However, as soon as this warm current appears, fish that prefer cold water will die in large numbers, causing fishermen to suffer disaster. This phenomenon is often most serious around Christmas, so fishermen who have suffered natural disasters and have no choice but to call it the Son of God - the Holy Infant. Later, in science, this term was used to refer to thousands of kilometers near Peru and Ecuador. When this phenomenon occurs, the sea surface temperature in a large area can be 3-6 degrees Celsius higher than normal.

The increase in water temperature in the vast Pacific Ocean has changed the traditional equatorial ocean currents and southeasterly trade winds, leading to global climate anomalies.

El Niño and La Niña are far away from the tropics

A few days ago, NASA stated that in the past three years, El Niño and La Niña have caused weather anomalies.

They will no longer affect the tropics, but other areas will be affected. Temperatures and water levels in tropical areas of the Atlantic and Pacific Ocean have returned to normal levels. Sea water levels in the central Pacific are 14 to 32 centimeters above normal, while water levels in the Bering Sea and the Gulf of Alaska are 5 to 13 centimeters below normal. William Patzelt, an oceanographer at the agency's Jet Propulsion Laboratory, said the current calm began with the disappearance of La Niña three months ago. He believes that the global climate system has returned to its state three years ago.

"La Niña" is really old

The latest ocean observation data sent back by the "Poseidon" satellites of France and the United States show that the climate change that has affected the Pacific Ocean in the past two years

< p>The "La Niña" phenomenon has weakened significantly, and the world's largest ocean will return to its former "quietness."

"La Niña" literally means "girl", which refers to a phenomenon of abnormal changes in water temperature in the eastern Pacific near the equator

"La Niña" is formed after a large area of ​​cold water caused by the "El Niño" phenomenon surfaces in the Eastern Pacific.

Because its characteristics are opposite to the "El Niño" phenomenon, it is also called "anti-El Niño" Phenomenon. Symptoms of the "La Nina" phenomenon are hurricanes, heavy rains and severe cold. Both it and the "El Nino" phenomenon will cause serious abnormalities in the global climate

.

According to French experts, "La Niña" generally appears after "El Niño". Under normal circumstances, the two phenomena

each last about a year. However, the "La Niña" phenomenon that began in 1998 lasted for two years and began to gradually weaken until June this year. They said that current research cannot explain why this "La Niña" phenomenon and the "El Niño" phenomenon that preceded it are unusually strong, nor can they explain what causes the "La Niña" phenomenon.

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The Nina phenomenon lasted one year longer than before.

Researchers had twice observed signs of weakening of the "La Niña" phenomenon in January and June last year, but subsequent

results proved that these were just illusions. After a brief respite, "La Niña" returned again. French experts emphasized that the latest data sent back by the satellite showed that the "La Nina" phenomenon has indeed weakened significantly, and the "girl" is really old this time.

The La Niña phenomenon affects my country's climate

China's climate showed a diversified trend in the first half of the year. After research and analysis, climate experts initially believe that the La Niña phenomenon

is affecting my country's climate. The main reason was the climate in the first half of the year.

"La Niña" means "Holy Maid" in Spanish and refers to a phenomenon in which water temperatures in the eastern Pacific near the equator drop abnormally.

The climate change characteristics it causes happen to be the same as those famous for It is the opposite of "El Niño" and is the strongest signal currently predicting anomalies in the global climate system.

Zhao Zhenguo, a researcher at the National Climate Center, believes that this year, under the influence of the La Niña phenomenon, the water temperature in the eastern equatorial Pacific has been low

, and the meridional circulation in East Asia has been abnormal, resulting in the north of my country being affected by cold weather since the beginning of spring. The northern airflow prevails, while the southeastern warm and humid airflow

is relatively weak. As a result, strong cold waves and strong winds occur frequently in the north, while rainfall continues to be low and temperatures remain high.

According to statistics, windy and sandy weather has been frequent in the northern region this spring. From March to April, 12 large-scale sandstorms and sandstorms occurred

The weather affected northwest and northern China. , the western part of Northeast China, the Huanghuai region, and even affected the Jiangzhun region. In May, there were three more regional or local sandstorms in the northwest region. The frequency and scope were so high that nearly 50 It is rare for the same period in the same year. Climate expert Chen Yu said that the frequency of sand and dust events in northwest China has been increasing year by year in the past 50 years.

Lu Juntian, a senior engineer at the National Climate Center, said that since 300 AD, there have been five frequent periods of sand and dust events in my country since 300 AD, with each cycle lasting 90 years. Around this time, sand and dust events have shown a significant increase trend in the past 10 years.

Talking about the reasons for the occurrence of sandstorms, Chen Yu believes that the formation and scale of sandstorms depend on the environment and climate.

From an environmental point of view, the increasingly serious desertification The problem cannot be ignored. But "there is no wind without waves". In terms of climate, the temperature in the northern region has risen rapidly since February this year, with an increase of 2 to 3 degrees Celsius, causing the soil to thaw.

Early on, dry soil layers appear in abundance. At this time, the rainy season had not yet come. Under the influence of the La Niña phenomenon, windy weather continued to occur in the northern region. The soil took advantage of the wind and sandstorms formed immediately.

The high temperature and lack of rain in the north is also a hot topic among people. From March to May this year, the national average temperature hit the highest level in the same period since 1961

Especially in the northern region, the temperature continues to be cold. high. Starting from February, most areas north of the Yangtze River have continued to receive less precipitation. For four consecutive months, the total precipitation has been less than 100 millimeters. In North China and northwest China, the precipitation has been less than 50 millimeters, which is lower than the same period in previous years.

More than 50% less, especially from February to April, the average precipitation in the northern region is only 23 mm, the lowest since the founding of the People's Republic of China. High temperatures and lack of rainfall have caused a rapid decline in soil moisture in the northern region, resulting in the most serious spring drought since the 1990s.

Zhao Zhenguo said that since 1992, except for 1998, the precipitation in the north from February to April in other years has been below the multi-year average

value, especially from June last year to the present, the precipitation in the north has been Precipitation in the region continues to be low, and soil moisture at the bottom is already very poor. At this time,

Under the influence of the La Niña phenomenon, northerly airflow prevails in northern my country, while the warm and humid airflow in the southeast is relatively weak. In addition,

the cold and warm air do not cooperate well, so this phenomenon For a long time, ideal rainfall conditions have not been formed in the northern region, resulting in continuous dry weather with little rain.

While the north is fighting drought, heavy rains are frequent in some areas south of the Yangtze River. In this regard, Lu Juntian pointed out that the heavy rain in the south is the result of local strong convective weather. From a large-scale basin perspective, the precipitation is still normal.

When talking about my country's overall climate characteristics and development trends, Lu Juntian said that judging from the trends of global climate in recent years, there is generally a trend of diversification, which is mainly due to global warming. In the context of climate warming, the result of the alternating effects of El Niño and La Niña phenomena

. In this environment, it is impossible for our country to become a peaceful paradise. He said that the national meteorological department is paying close attention to future atmospheric climate changes and making timely forecasts to minimize the losses caused by disastrous weather.

La Niña - where do you come from

Last year, after the "El Niño" phenomenon that lasted for more than a year quickly disappeared, "La Niña" immediately appeared.

So what is La Niña?

La Niña refers to the phenomenon of continued abnormally cold sea surface temperatures in the eastern and central equatorial Pacific (the exact opposite of El Niño

). It is a new term used in the meteorological and oceanographic circles. It means "little girl", which is the opposite of El Niño, which means "Christ Child

". It is also called "anti-El Niño" or "cold event".

El Niño and La Niña are abnormal manifestations of alternating cold and warm sea temperatures in the central and eastern equatorial Pacific. This process of cold and warm sea temperature changes constitutes a cycle, which occurs after El Niño. La Nina is nothing unusual. El Niño will also follow the same trend. But judging from records since 1950, El Niño occurs more frequently than La Niña. The frequency of La Niña phenomena is slowing down and its intensity is weakening under the current background of global climate warming. Especially in the 1990s, there were three consecutive El Niño events from 1991 to 1995, but there was no La Niña in between.

So, how does La Niña form? El Niño is associated with warming sea temperatures in the central and eastern equatorial Pacific and weakening trade winds, while La Niña is associated with cooling sea temperatures and strengthening trade winds in the central and eastern equatorial Pacific. Therefore,

La Niña is actually the product of the simultaneous interaction of the tropical ocean and atmosphere.

Trade winds refer to the winds blowing from the tropics to the equator in low air. They are called "northeast trade winds" in the northern hemisphere, and "southeast trade winds" in the southern hemisphere. "Trade Wind", the Spaniards who lived in South America a long time ago used this constant easterly

wind to sail to Southeast Asia for business activities. Therefore, trade winds are also known as trade winds.

The movement of the ocean surface is mainly controlled by the surface wind. The existence of trade winds causes a large amount of warm water to be blown to the equatorial west

Pacific region. In the equatorial east Pacific region, the warm water is blown away, and is mainly replenished by cold water below the sea surface. The equator

The sea surface temperature in the eastern Pacific is significantly lower than that in the western Pacific. When the trade winds strengthen, the upwelling of deep seawater in the eastern equatorial Pacific becomes more intense

resulting in abnormally low sea surface temperatures, causing the airflow to sink in the eastern equatorial Pacific and the airflow to rise in the west

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The rising motion is more intensified, which is conducive to the strengthening of trade winds, which further aggravates the development of cold water in the eastern equatorial Pacific and triggers the so-called La Niña phenomenon.

La Niña also has an impact on climate. La Niña is the opposite of El Niño. With the disappearance of El Niño and the arrival of La Niña, weather and climate disasters will also change in many parts of the world. Generally speaking, La Niña is not very mild in temperament

It may also bring disasters to many areas around the world. Its climate impact is roughly opposite to El Niño,

but its intensity and impact Not as much as El Niño.