How does La Nina affect the climate in China?

Influence of El Nino and La Nina on Climate in China

What is La Nina phenomenon? La Nina phenomenon, like El Ni? o phenomenon, is a large-scale seasonal abnormal change of seawater temperature. This will lead to abnormal weather in some areas, thus forming meteorological disasters. El Nino phenomenon refers to the large-scale abnormal increase of seawater temperature every few years in the central and eastern equatorial Pacific. This phenomenon obviously appears on the east coast of the South Pacific, that is, the west coast of Ecuador, Peru and other countries in South America. It is a world-famous fishing ground, and its fishery output accounts for about 1/5 of the world total. But every two to seven years, the seawater temperature here will rise abnormally, leading to the death of fish and birds, the migration of marine animals and the sharp decline of fishery harvest. Why this phenomenon occurs is still unclear. It usually appears around Christmas or a month or two later, so Spanish-speaking locals call it "El Nino", that is, "El Nino". La Nina phenomenon is just the opposite of El Ni? o phenomenon, which refers to the abnormal cooling of seawater temperature in the central and eastern equatorial Pacific. For this reason, Spanish-speaking locals call it "La Nina", which means "saint". Both El Nino and La Nina will cause abnormal changes in the global climate system and form meteorological disasters. El Nino phenomenon leads to the increase of atmospheric temperature over the ocean, which destroys the dynamic balance of the normal distribution of heat and water vapor in the atmospheric circulation. The result of this abnormal rise in sea water and temperature is often an abnormal weather change on a global scale. So that some areas can't be cold when it is cold, and some areas can't be hot when it is hot; In those areas that used to be sunny and rainy, rainfall suddenly increased, leading to flooding, while in those areas with sufficient rainfall, there was no rain for a long time under the scorching sun. In the year of El Nino, the rainfall in the central and eastern equatorial Pacific usually increases greatly, while the western Pacific such as Australia and Indonesia is dry and rainless. In many places in the northern hemisphere, it will be warm in winter and cool in summer, high in winter and low in summer. La Nina usually follows El Nino. When El Nino occurred, the surface seawater temperature in the equatorial eastern Pacific Ocean rose abnormally, and the heat spread into the air, and the hot air was blown away by the strong wind over the Pacific Ocean, and the upper seawater temperature gradually decreased. At this time, the cold seawater in the depths of the ocean turned up again, further reducing the surface temperature of seawater. If a large area of upper seawater is continuously cooled for more than 6 months, and its temperature is lower than 0.5℃ all the year round, La Nina phenomenon will be formed. The season of El Nino phenomenon is not fixed, there are six months and one or two years. It usually happens every 2 to 7 years. However, since the 1990s, this phenomenon has appeared more and more frequently, not only with a shorter cycle, but also with a longer duration, and its influence on China has become more and more obvious. Although the exploration and research on El Ni? o and La Ni? a are still in progress, scientists generally believe that the intensification of this phenomenon is closely related to global warming, that is, it has a certain relationship with human activities. The influence of El Nino on China is that the intensity of summer monsoon blowing from the southeast ocean to China is greatly weakened, which leads to the location of summer rainfall belt in China being southward. Results As a result, heavy rain hit the south, and the temperature in hot season was much lower than in previous years. In the north, however, there is continuous high temperature and no rain, resulting in a rare drought. El Nino caused floods in the south and droughts in the north. This El Nino phenomenon is the chief culprit that caused the flood in the whole Yangtze River basin from 65438 to 0998. La Nina phenomenon has a much smaller catalytic effect on meteorological disasters. Generally speaking, in the year of La Nina, there will be more rainfall in Indonesia, eastern Australia, northeastern Brazil, India and southern Africa. There will be droughts in the eastern and central Pacific, the southern United States and equatorial Africa. The impact on our country will not be obvious. Generally, it gets colder in winter and hotter in summer. The number of tropical cyclones generated in the western Pacific and South China Sea and landing in China is slightly higher than normal. However, this time La Ni? a phenomenon had a great influence in China, which caused the worst snow disaster in southern China in a century. This is not as simple as a little cold in winter, and this snowstorm can't be completely attributed to La Nina phenomenon. However, this ice and snow disaster reminds us that La Ni? a phenomenon may not only produce an unremarkable winter Leng Xia fever in China as in the past, but also the number of tropical cyclones landing in China may not be just a little more. It is likely to get very hot this summer, especially when tropical cyclones make landfall in China.

El Nino phenomenon, also known as El Nino flow, is a climatic phenomenon caused by the eastward shift of Walker circulation circle, which leads to the imbalance between the ocean and the atmosphere in the Pacific equatorial belt. 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.

El Nino has a serious impact on our climate. 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.

La Nina phenomenon refers to the phenomenon that the sea surface temperature in the eastern and central equatorial Pacific continues to be abnormally cold (just the opposite of El Ni? o phenomenon). It is characterized by the obvious cooling of the East Pacific, accompanied by global climate chaos, which always appears after the El Ni? o phenomenon. La Nina phenomenon is a modified transitional 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. El Nino is related to the warming of sea surface temperature and the weakening of trade winds in the equatorial Middle East Pacific, while La Nina is related to the cooling of sea surface temperature and the strengthening of trade winds in the equatorial Middle East Pacific. So La Nina is actually the product of the interaction between tropical ocean and atmosphere.

La Nina's influence on China's climate: We are in La Nina state this year, that is, the sea surface temperature in the equatorial eastern Pacific Ocean is below 0.5 degrees lower than normal, which has a very obvious influence on China's climate. Under the influence of La Nina phenomenon, the meridional circulation in East Asia is abnormal, which is very beneficial to the southward movement of cold air in northern China. It has given us a cold winter, so we can see that this cold winter has already appeared this year. Since 2008, the high pressure in Asia has been very active, forming a cold air mass in the south, affecting China, and there has been a large-scale gale and cooling weather. However, due to the active warm air mass in the south this year, a large number of warm and humid air currents from the Pacific Ocean and the Indian Ocean frequently patronize the southern region. When the powerful cold air mass from Mongolia and Siberia quickly moved south to meet the warm and humid air mass, the cold and warm air just merged into one. Affected by these two air currents, there have been more rainy and snowy weather recently, especially in the Yangtze River basin, and the low temperature weather has lasted for a long time. If there is only a strong cold air mass without a large amount of water vapor provided by warm and humid air mass, there will only be strong winds and cool weather in the south; If there is only a large amount of water vapor provided by warm and humid air masses, there will be no disastrous weather at all without the arrival of cold air masses. When both are ready, disaster comes.

When China was severely hit by a snowstorm, there was a sharp temperature drop of 20 degrees Celsius in the central United States, and snowstorms (2008+0) appeared from time to time; Central Asia, which has not snowed for a hundred years, suddenly snowed 10mm, setting a new record for Baghdad 100 (2007+02). In the summer of 2007, the floods in western Europe were serious, and Britain and France suffered huge losses (summer of 2007). Since the beginning of winter, the temperature in the northern edge of Russia has hit a new low, once reaching MINUS 50 degrees Celsius ... La Nina is still not over, and the situation is still very grim. ...