Traditional Culture Encyclopedia - Weather inquiry - Is El Nino a climatic phenomenon or an astronomical phenomenon?
Is El Nino a climatic phenomenon or an astronomical phenomenon?
ELNINO El Nino in mbth? O phenomenon
A summary of El Nino phenomenon
El Nino phenomenon, also known as El Nino current, 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 Ni? 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.
The basic feature of El Nino phenomenon is that the sea surface temperature along the Pacific coast rises abnormally, the sea water level rises, and a warm current flows southward. It turns cold water in the East Pacific into warm water, causing tsunamis and storms, causing drought in some areas and excessive rainfall in others.
The whole process of El Nino is divided into occurrence period, development period, maintenance period and attenuation period, which generally lasts for about one year, and the change of atmosphere lags behind the change of seawater temperature.
Today, with the highly developed meteorological science, people have understood that the central Pacific Ocean is the main power source of summer climate change in the northern hemisphere. Usually, there is a northward Peruvian cold current in the Pacific Ocean on the west side of the South American continent, and part of it turns into an equatorial flow and moves westward. At this time, the monsoon blowing westward along the sea near the equator makes the warm current accumulate to the west side of the Pacific Ocean, while the low-level cold sea water rises to the east side, which makes the sea temperature in the western Pacific Ocean south of the Philippines and north of New Guinea rise. This part of the sea area is called "equatorial warm pool", and the seawater temperature in the east of the same latitude is relatively low. There is also a temperature difference in the atmosphere over the two sea areas. The temperature in the east is low and the air pressure is high, and the cold air sinks and flows westward. The temperature in the west is high and the air pressure is low. After the hot air rises, it turns to the east. In this way, an atmospheric circulation (Walker circulation) is formed in the middle of the Pacific Ocean, and the southeast trade wind is formed near the sea level. But sometimes, this pressure difference will be lower than the multi-year average, and sometimes it will increase. This phenomenon of atmospheric change is called "Southern Oscillation". In 1960s, meteorologists found that El Nino was closely related to the Southern Oscillation. When the pressure difference decreased, El Nino appeared. After El Nino, due to the warming of warm current, the monsoon flowing from east to west in the Pacific Ocean was greatly weakened, which significantly changed the atmospheric circulation and greatly affected the climate of countries along the Pacific Ocean. The originally wet area was dry, and there was a flood in the dry area. When this pressure difference increases, the seawater temperature will drop abnormally, which is called "La Nina phenomenon".
After the 1960s, with the progress of observation methods and the development of science, it was found that El Ni? o phenomenon not only appeared in the coastal areas of South America and other countries, but also spread all the sea areas along the equator of the eastern Pacific Ocean and countries around the Pacific Ocean. In some years, even the Indian Ocean coast will be affected by the climate anomaly caused by El Ni? o, and a series of natural disasters will occur. Generally speaking, it makes the climate in the southern hemisphere hotter and drier, and the climate in the northern hemisphere colder and wetter.
In recent years, scientists have put forward some new explanations for the El Ni? o phenomenon, that is, El Ni? o may be related to submarine earthquakes, changes in seawater salinity and changes in atmospheric circulation.
El Nino occurs periodically, about once every 2-7 years. During the 20 years from 65438 to 0997, El Nino occurred five times in 76-77, 82-83, 86-87, 9 1-93 and 94-95 respectively. The El Ni? o phenomenon during 1982- 1983 was the most serious since this century, which caused about 1500 deaths and 8 billion US dollars in property losses all over the world. After entering the 1990s, with global warming, El Nino phenomenon appeared more and more frequently.
Due to the development of science and technology and the attention of countries all over the world, scientists have deepened their understanding of this climate anomaly by adopting a series of scientific research activities such as forecasting model, ocean observation and satellite reconnaissance, and air-sea coupling. Firstly, it is recognized that the physical process of El Ni? o phenomenon is the result of the interaction between the ocean and the atmosphere, that is, the change of ocean temperature is related to the atmosphere. Therefore, after 1980s, scientists called El Nino "Anceaux". Secondly, tropical ocean warming occurs not only in the Chilean waters of South America, but also in the eastern and western Pacific. No matter where it happens, it will quickly lead to obvious global climate anomalies. This is the strongest signal of climate change, which will lead to serious natural disasters, such as droughts and floods in many parts of the world.
El Nino means "child" in Spanish. El Nino is a phenomenon that leads to an abnormal rise in sea surface temperature around Christmas in the cold ocean current area on the west coast of the United States. It is like a "warm pool", which changes the atmospheric heating field through the change of surface temperature, thus bringing changes to the weather in various places, causing floods in the original dry and rainy places, while the rainy places are prone to long-term drought and lack of rain.
From the position of main rain belts in China from June to August, 75% of the rain belts are located in the Yangtze River and Huaihe River basins in El Ni? o year and summer. Figuratively speaking, the low-frequency oscillation of tropical atmospheric circulation can be compared to tropical heartbeat. The occurrence of El Nino events is like a heart attack in the tropics, which makes the regular low-frequency oscillation abnormal.
When the above El Nino phenomenon occurred, it spread all over the central, eastern and Pacific oceans, and the positive anomaly of surface water temperature was as high as 3℃ or above. The strong rise in seawater temperature has led to a great decrease in plankton in the water, which has hit Peru's fishery production and led to floods or droughts in Ecuador and other equatorial Pacific regions. This El Nino phenomenon is called El Nino event. It is generally believed that the sea surface temperature anomaly for three consecutive months is above 0.5℃, which can be considered as an El Ni? o event. On the contrary, if the negative sea surface temperature anomaly along the coast of South America is above 0.5℃ for three consecutive months, it is considered as an anti-El Ni? o event, also known as La Ni? a event. At present, according to the research of meteorologists, it is generally believed that the occurrence of El Ni? o event is a harbinger of climate disasters in many parts of the world, so its monitoring has become an important content in climate monitoring.
El Nino has a serious impact on the climate in China.
First, the number of typhoons has decreased. After the El Ni? o phenomenon, the number of tropical storms (typhoons) in the northwest Pacific and the number of landings in China's coastal areas are less than normal.
Secondly, the northern part of China is prone to high temperature and drought in summer. Usually in El Nino, the summer monsoon in China is weak, and the monsoon rain belt is south, which is located in the middle of China or south of the Yangtze River. Drought and high temperature often occur in summer in northern China. 1997 After the strong El Ni? o, the drought and high temperature in northern China were very obvious.
Third, southern China is prone to low temperatures and floods. One year after El Nino, the southern part of China, including the Yangtze River basin and the south of the Yangtze River, is prone to floods. The once-in-a-century floods in China, such as 193 1, 1954, 1998, all occurred one year after El Nino ... El Nino was one of the important factors that affected the 1998 catastrophic floods in China.
Finally, in the winter after El Nino, the northern part of China is prone to warm winters.
According to the meteorological data in recent 50 years, after El Nino, there is a high probability of high temperature in winter in China, and summer precipitation in southern China tends to be more in the following year, while large-scale drought often occurs in northern China.
According to historical records, since 1950, there have been 13 El Nino phenomena all over the world. The one that happened in 1997 and continues to this day is the most serious. Mainly manifested in: from the northern hemisphere to the southern hemisphere, from Africa to Latin America, the climate has become weird and incredible. A cool place is like a fire. It suddenly snows in warm spring, but it doesn't rain when the rainy season comes, but floods in dry season. .....
Scientists believe that the occurrence of El Nino phenomenon is related to the deterioration of human natural environment, the direct result of the intensification of global greenhouse effect, and the result of human beings demanding too much from nature and not paying attention to environmental protection.
According to the research on the relationship between the change law of solar activity and El Ni? o in the past hundred years, scientists found that the period from sunspot reduction to valley value is the frequent period of El Ni? o, with two or three El Ni? o occurrences.
- Previous article:How about March 8th?
- Next article:English weather vocabulary
- Related articles
- How many kilometers is it from Shuiyang Town, Xuancheng City, Anhui Province to Yanchi Community?
- How long can the weather forecast last?
- The weather in Huai 'an in September
- Is there a RT Mart in Neijiang, Sichuan?
- 20 10 what's the clear weather like in Yantai?
- Confusion can describe the weather?
- Does xinji city belong to Shijiazhuang?
- English weather self-introduction
- The weather in Luoxingyi
- If there is strong wind, can the greenhouse be opened on both sides?