El Nino and La Nina phenomena
La Nina, which means "La Nina-"little girl, saint "in Spanish, is the inverse phenomenon of El Niñ o phenomenon, which refers to the abnormal drop of water temperature in the eastern Pacific near the equator, which is characterized by obvious cooling in the eastern Pacific, accompanied by global climate chaos, and always appears after El Niñ o phenomenon.
Meteorologists and oceanographers use it to refer to the large-scale continuous abnormal cooling of seawater in the eastern and central equatorial Pacific (the surface temperature of seawater is lower than the climate average by more than 0.5℃ for more than 6 months). La Nina is also known as the anti-El Nino phenomenon.
La Nina usually follows the El Niñ o phenomenon. La Nina will appear in the second year of El Niñ o, sometimes lasting for two or three years. During 1988-1989, 1998 -200 1 year, a strong La Nina phenomenon occurred, which made the seawater temperature in the eastern and central Pacific Ocean lower than normal 1 ~ 2℃,1999. Some scientists believe that La Nina tends to weaken due to the trend of global warming.
The last La Nina phenomenon appeared in 1998 and lasted until the spring of 2000. El Nino and La Nina usually appear alternately, which have roughly opposite impacts on the climate. Through the energy exchange between the ocean and the atmosphere, the atmospheric circulation is changed, thus affecting climate change. According to the monitoring data in recent 50 years, the frequency and intensity of El Nino are more than La Nina.
La Nina often happens after El Nino, but it doesn't always happen. It takes about four years for El Nino and La Nina to transform into each other.
Chinese oceanographers believe that the catastrophic flood disaster in China in 1998 was caused by "El Nino-La Nina phenomenon" and ecological deterioration in the Yangtze River basin.
Oceanographers and meteorologists in China have noticed that last year's El Niñ o phenomenon (ocean warming) in the tropical Pacific turned into La Niñ a phenomenon (seawater cooling) within one month. This unprecedented situation is one of the reasons for the surge in rainfall in the Yangtze River basin.
The El Nino phenomenon made the climate in China abnormal. 1998 from June to July, there was frequent rainfall in the south of the Yangtze River and South China, and serious floods occurred in the Yangtze River basin and the two lakes basin. The water level of some rivers has exceeded the warning water level for a long time, and the rainfall in parts of Guangdong, Guangxi and Yunnan is also above 50%. Waterlogging also occurs in parts of North China and Northeast China. La Nina can also cause climate anomalies. Chao Jiping, academician of the China Academy of Sciences and honorary director of the National Marine Environmental Forecasting Research Center, said that the current situation is that the influence of El Niñ o has not completely disappeared, but the influence of La Niñ a has started again, which makes the climate state of China extremely complicated. Generally speaking, after the large-scale warm and humid air caused by El Nino moves to the higher latitudes in the northern hemisphere, it meets the cold air in the north and exchanges cold and warm, resulting in an increase in rainfall. But after June, when summer comes and the rain belt moves northward, the flood season in the Yangtze River basin should be over. But then La Nina appeared, the air in the south became cold and sank, and the warm and humid airflow that had moved northward returned to fill the vacuum. In fact, the subtropical high reached 30 degrees north latitude at 10 in July, and suddenly retreated southward to 18 degrees north latitude. This phenomenon has never happened in history.
La Nina is an overcorrection phenomenon after El Nino. This hydrological feature will cause the water temperature in the eastern Pacific to drop, which will lead to drought. On the contrary, the water temperature in the western Pacific will rise, and the precipitation will be significantly higher than normal. Scientists believe that La Nina, a hydrological phenomenon, will not have a significant impact on the world climate, but will bring more rainfall to Guangdong, Fujian, Zhejiang and even the entire southeast coast in a certain period of time.
El Nino phenomenon, also known as El Nino flow, is a climatic phenomenon caused by the imbalance between the ocean and the atmosphere in the equatorial Pacific. Under normal circumstances, the monsoon air flow in the tropical Pacific moves from America to Asia, keeping the surface of the Pacific Ocean warm and bringing tropical rainfall around Indonesia. However, this pattern is disturbed every 2-7 years, and the wind direction and ocean current are reversed. The heat flow in the surface of the Pacific Ocean turns eastward to America, and then takes away tropical rainfall, resulting in the so-called "El Niñ o phenomenon".
The word "El Nino" comes from Spanish, which means "El Nino". /kloc-At the beginning of the 9th century, in Spanish-speaking countries such as Ecuador and Peru in South America, fishermen found that every few years, that is, from June of 10 to March of the following year, a warm current moved southward along the coast, which significantly increased the surface seawater temperature. The Peruvian cold current originally prevailed on the east coast of the Pacific Ocean in South America. Fish that move with the cold current make Peru's fishing ground one of the three largest fishing grounds in the world. But when this warm current appears, a large number of fish who like cold water will die, leading to the extinction of fishermen. Because this phenomenon is often the most serious around Christmas, fishermen who suffer from natural disasters and are helpless are called the son of God-El Nino. Later, in science, the term was used to indicate the abnormal warming of sea surface temperature in the eastern Pacific Ocean thousands of kilometers near Peru and Ecuador. When this happens, the sea water temperature in a wide range can be 3-6 degrees Celsius higher than normal. The rising water temperature in the vast waters of the Pacific Ocean has changed the traditional equatorial currents and southeast trade winds, resulting in global climate anomalies.
El Nino and La Nina are far from the tropics.
A few days ago, NASA said that in the past three years, El Nino and La Nina caused abnormal weather.
They will no longer affect the tropics, but other regions will also be affected by them. Natural gas in tropical Atlantic and Pacific oceans.
The medium water level has returned to the normal level. The seawater level in the central Pacific Ocean is higher than normal 14 ~ 32 cm, while Bering
However, the water level in Alaska Sea and Gulf is 5 ~13cm lower than normal. William, an oceanographer at the Jet Propulsion Laboratory of the Bureau.
Patzelt said that the current calm began with the disappearance of La Nina three months ago. He believes that the global climate system has been restored.
Go back to the state three years ago.
La Nina is really old.
The latest ocean observation data sent back by Poseidon satellites in France and the United States show that it has affected the Pacific Ocean in the past two years.
La Nina phenomenon is obviously weakened, and the world's largest ocean will restore its former "tranquility".
"La Nina" literally means "girl" and refers to the abnormal change of water temperature in the eastern Pacific near the equator.
Phenomenon. "La Nina" is a huge cold water area after the phenomenon of "El Niñ o" surfaced in the East Pacific.
Cheng, because of its characteristics contrary to the "El Nino" phenomenon, is also known as the "anti-El Nino" phenomenon. "La Nina"
The symptoms of this phenomenon are hurricanes, heavy rains and severe cold, and the El Niñ o phenomenon will cause serious changes in the global climate.
Often.
According to French experts, "La Nina" usually appears after "El Nino". Usually, there are two phenomena.
Each elephant can live for about a year. However, the "La Nina" phenomenon, which started at 1998, lasted for two years until now.
It began to weaken gradually in June 2006. They said that the current research can not explain the phenomenon of "La Nina" and its
Why the phenomenon of "El Nino" appeared before was extremely strong does not explain what caused the "pull"
The Nina phenomenon lasted one year longer than before.
Researchers observed signs of "La Nina" weakening twice in June and June last year, but later,
Facts have proved that these are just illusions. After a little breathing, "La Nina" made a comeback again. French experts stressed that
It is said that the latest data sent back by this satellite shows that the phenomenon of "La Nina" has indeed obviously weakened, and "girl" is this time.
Really old.
La Nina phenomenon affects the climate in China.
In the first half of the year, the national climate showed a diversified trend. After research and analysis, climate experts initially believe that La Nina phenomenon.
This is the main reason that affects the climate in the first half of our country.
"La Nina" means "Saint" in Spanish, which means that the water temperature in the eastern Pacific near the equator has dropped abnormally.
Phenomenon, the characteristics of climate change caused by it are just the opposite of the famous "El Nino" and the same as El Nino.
It is the strongest signal to predict the global climate system anomaly at present.
Zhao Zhenguo, a researcher at the National Climate Center, believes that this year, under the influence of La Nina phenomenon, the water temperature in the equatorial eastern Pacific Ocean.
On the low side, the abnormal meridional circulation in East Asia leads to the northerly airflow prevailing in the north of China since the spring, while the warm and humid airflow prevails in the southeast.
Relatively weak. It leads to frequent strong cold waves and strong winds in the north, but the rainfall continues to be less and the temperature remains high.
According to statistics, there are frequent sandstorms in northern China this spring, and there are 12 large-scale sand blowing and sandstorms in March and April.
The weather, including northwest, north China, northeast, Huanghuai area, even spread to Jiangzhun area, in May.
There have been three regional or local sandstorms in the northwest of China, and their frequency and scope are the same as those in the past 50 years.
Menstruation is rare. Chen Yu, a climate expert, said that in the past 50 years, the frequency of dusty weather in northwest China has increased year by year.
Lu, a senior engineer at the National Climate Center, said that there have been five sandstorms in China since 300 AD.
In the development period, each cycle lasts about 90 years, and in the past 10 years, dust events showed a significant increase trend.
Talking about the causes of sandstorms, Chen Yu believes that the formation and scale of sandstorms depend on the environment and climate.
Su Gang, from the environmental point of view, the increasingly serious problem of desertification can not be ignored. But "there is no smoke without fire", in terms of climate,
Generally speaking, since February this year, the temperature in the northern region has risen rapidly, with a high range of 2 to 3 degrees Celsius, which has caused the soil to thaw.
A large number of dry soil layers appeared in advance. At this time, the rainy season has not yet arrived. Under the influence of La Nina phenomenon, the northern region has even
The windy weather continues to appear, and sandstorms form immediately after the soil borrows wind.
High temperature and little rain in the north are also hot topics. From March to May this year, the national average temperature reached 196 1.
It is the highest in the same period since, especially in the northern region. Since February, precipitation has decreased in most areas north of the Yangtze River.
It continues to be less, and the total precipitation is less than 100 mm for four consecutive months, and less than 50 mm in North China and Northwest China, which is more than normal.
Less than 50%, 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 temperature reheating
Coupled with the lack of rain, the soil moisture in the northern region declined rapidly, forming the worst spring drought since the 1990 s.
Zhao Zhenguo said that since 1992, except 1998, February to April in other years has been the multi-year average of precipitation in the north.
Below the numerical value, especially since June last year, the precipitation in the northern region has been less, and the moisture content in the bottom of the soil has been very poor. At this time,
Affected by La Nina phenomenon, the northerly airflow prevails in northern China, while the warm and humid airflow in the southeast is relatively weak, plus
The combination of cold and warm air is unfavorable, and the ideal rainfall conditions have not been formed in the northern region.
Persistent dry and rainy weather.
During the drought-resistant period in the north, heavy rains occurred frequently in some areas south of the Yangtze River. In this regard, it is pointed out that Nanlu
Rainstorm weather is the result of local strong convective weather, and precipitation is normal in a wide range of river basins.
When talking about the overall climate characteristics and development trend of China, Lu said that from the perspective of global climate change trends in recent years, in general,
There is a trend of diversification, which is mainly the intersection of El Niñ o and La Nina in the context of global warming.
The result of substitution. In this environment, China cannot be a peaceful "Xanadu". He said that this country
The meteorological department is paying close attention to the future atmospheric climate change, forecasting it in time, and minimizing the losses caused by disastrous climate.
Lost.
La Nina-Where are you from?
Last year, after the "El Nino" phenomenon that lasted for more than a year quickly disappeared, "La Nina" immediately appeared in black and pink.
So what is La Nina?
La Nina refers to the phenomenon that the sea surface temperature in the eastern and central equatorial Pacific Ocean continues to be abnormally cold (similar to El Niñ o phenomenon).
Conversely). This is a new term used in meteorology and oceanography. It means "little girl", just as it means "El Nino"
On the contrary, El Nino is also called "anti-El Nino" or "cold event".
El Nino and La Nina are abnormal manifestations of alternating SST changes in the equatorial, Middle East and Pacific Ocean.
The process of cold and warm changes constitutes a cycle, and it is not uncommon for La Nina to appear after El Nino. Similarly, Rani
El Nino will appear after Nina. However, according to the records since 1950, the frequency of El Niñ o is higher than that of La.
Nina. Under the background of global warming, the frequency and intensity of La Nina phenomenon are slowing down. Especially in 1990.
From 199 1 to 1995, there were three consecutive El Ninos without La Nina.
So, how was La Nina formed? El Nino and SST warming and the trade winds in the equatorial Middle East and the Pacific Ocean
On the other hand, La Nina is related to the cooling temperature in the central equatorial and eastern Pacific and the enhancement of trade winds. Therefore,
In fact, La Nina is the product of the interaction between tropical ocean and atmosphere.
The trade wind refers to the prevailing wind in the lower atmosphere blowing from the tropical region to the equatorial region, which is called "Northeast Trade Wind" in the northern hemisphere.
The southern hemisphere is called the "southeast trade wind". The Spaniards who lived in South America a long time ago took advantage of this continuous eastward trend.
The wind sailed to Southeast Asia for commercial activities. So trade winds are also called trade winds.
The motion of the ocean surface is mainly constrained by the sea surface wind. The existence of trade winds makes a lot of warm water blown to the west of the equator.
In the Pacific, the warm water in the equatorial eastern Pacific is blown away, which is mainly supplemented by cold water below the sea surface.
The SST in the eastern Pacific is obviously lower than that in the western Pacific. When the trade winds strengthen, the upwelling phenomenon of deep seawater in the equatorial eastern Pacific becomes more serious.
Strong acceleration leads to abnormally low sea surface temperature, which makes the airflow in the eastern equatorial Pacific sink, while the airflow is on the western surface.
The strengthening of the ascending movement is conducive to the strengthening of the trade winds, thus further intensifying the development of cold water in the equatorial eastern Pacific Ocean, triggering the so-called
La Nina phenomenon.
La Nina also has an impact on the climate. La Nina and El Nino are opposite in nature. With the disappearance of El Nino, pull
With the arrival of Nina, the weather and climate disasters in many parts of the world will also change. Generally speaking, La Nina is not sex.
The situation is very mild, and it will also bring disasters to many parts of the world, and its climate impact is roughly the opposite of that of El Niñ o.
But its intensity and influence are not as good as that of El Nino.