Worried about extreme weather this winter, La Nina's annual probability is 87%. Why did this happen?

The climate change of 202 1 will usher in a more serious change, that is, the so-called extreme weather will become more and more complicated. Meteorologists have predicted the weather in advance this year, and the probability of cold winter this year is extremely high, and the main reason behind this is La Nina effect. So what is La Nina phenomenon? ?

1. Is it likely to be very cold this winter?

202 1 The probability of extreme weather is extremely high. This summer, there was persistent high temperature in North America, and there was heavy precipitation in China and Henan. Focusing on the extreme high temperature weather in southern China in recent 10, we feel that there are more extreme weather this year than before. Experts predict that there will be more extreme cold weather this winter, which is caused by global warming. ?

Second, La Nina phenomenon?

The most direct manifestation of La Nina phenomenon is that the sea water temperature in the equatorial eastern Pacific is abnormally low, which affects the atmospheric circulation, and the sea water temperature will affect the upper atmospheric velocity. Due to the low radiant heat of seawater, the atmospheric density above it will become higher and the air pressure will become higher, thus becoming drier. The opposite will happen on the hot sea. Under the pressure gradient change of the north-south air mass, heavy and dry air will sink south, while the high-pressure air mass in the eastern Pacific will drive water vapor and be forced to land in Indonesia, which will directly lead to the continuous increase of precipitation in Indonesia. ?

Experts predict that this year's La Nina effect will last from June 1 1 to 2022. La Nina will squeeze the subtropical high, and then let the cold air continue to form a group to the south, resulting in the continuous cooling in the southern region after June this year 1. It is expected that La Nina will return to the Earth this winter, with an annual probability of about 87%, resulting in extremely cold or heavy snowfall this winter. For us, it is still necessary to do relevant protective work to avoid being affected by extremely cold weather.