About the global climate

El Nino is the product of the interaction between tropical atmosphere and ocean. It used to mean abnormal warming of equatorial sea surface, but now it is defined as global climate anomaly caused by air-sea interaction. El Nino phenomenon is an example of a strong coupling event between atmospheric circulation and ocean circulation. The stress exerted by atmospheric circulation (wind) on the ocean is the main driving force of ocean circulation. At the same time, as we can see, the heat from the ocean, especially evaporation, has a great influence on the atmospheric circulation. The simplified model of El Nino shows the role of different fluctuations in the process of ocean energy transfer. In this simplified model, the waves in the ocean are called Rossby waves, which propagate westward from the unusually warm sea near the equator. When it reaches the western boundary of the ocean, it will be reflected into a different wave called kelvin wave. This fluctuation spread eastward, offsetting or changing the original signs of abnormal temperature in the warm sea, and causing cooling events. The time required for this half cycle in the whole El Ni? o event is determined by the propagation speed of these waves, which takes about 2 years.

This phenomenon is essentially driven by ocean dynamics, and the corresponding atmospheric change is determined by sea surface temperature (in turn, atmospheric change will strengthen the distribution pattern of ocean temperature), and the distribution of sea surface temperature is determined by ocean dynamics, so the El Ni? o phenomenon represented by the above simplified model is predictable in nature.

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 Ni? 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 Ni? 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 Ni? o.

But its intensity and influence are not as good as that of El Nino.