Xinhua News Agency, Beijing, Dec. 21 (Xinhua) -- News Analysis: Why is it still so cold under global warming?
Xinhua News Agency reporter Huang Yao.
Recently, the temperature in most parts of central and eastern China has continued to be low, and the ** Meteorological Observatory has issued a low temperature warning for a week, and many members of the public feel "as if living in a refrigerator".
According to the forecast, from the 21st to the 24th, the daily minimum temperature or average temperature in the northeast of Northwest China, the central and western parts of Inner Mongolia, North China, Northeast China, Huanghuai and most of the southern regions was more than 5 lower than that of the same period in history, and more than 7 in some areas.
Why do temperatures continue to be sluggish?**Xu Jun, chief forecaster of the Meteorological Observatory, analyzed that from the 13th to the 16th, a strong cold wave process affected China, and there was a strong cold air from the 18th, causing the temperature to drop again and again.
According to the statistical analysis of historical data, the winter temperature in China is generally warm under the background of El Niño, but the periodic cold air activities are more frequent, that is to say, the fluctuations of cold and warm are more obvious.
Liu Yunyun, chief forecaster of the National Climate Center, said that the intensity of the cold air process is not only affected by El Niño, but also has a lot to do with the disturbance of the Arctic vortex and the westerly wind belt in the middle and high latitudes. Since mid-December, the Arctic Vortex** has been bicentric, located over Greenland and Siberia. With the violent distortion of the westerly wind belt over Eurasia and the abnormal strengthening of the Siberian high, the southerly wind in most parts of China has changed from the prevailing southerly wind to the northerly wind, and the cold air has moved southward, resulting in a sharp drop in temperature.
On the other hand, El Niño will strengthen the subtropical high in the western Pacific, causing more water vapor from the tropics to be transported to the Chinese continent. Therefore, the cold wave process from the middle and high latitudes combined with the abundant water vapor conditions from the low latitudes led to a large range of snowfall in the central and eastern parts of China. The increase in albedo in clear skies caused by snow on the ground also led to a slower recovery in the later period.
Not long ago, the World Meteorological Organization declared 2023 to be the hottest year on record in human history, does this contradict the recent persistent low temperatures?
Experts say that when we talk about a certain year or month, we do not determine whether the average temperature over the entire period is significantly higher or lower than that of the same period in history. For example, from November 3 to 7 this year, there was a cold wave weather process in most parts of China, and the temperature fell off a cliff, and the average temperature during this period was much lower than the same period in history, but the average temperature of the whole autumn was still the highest since 1961, which was called "the warmest autumn".
In the context of global warming, why is the cold air still so strong?
There is a large temperature difference between the equator and the polar regions, and this difference has led to the formation of a strong circle of westerly winds around the periphery of the polar circle, known as the westerly jet stream, which acts like a fence to confine the cold polar air, and the stable polar vortex is confined to the Arctic region by the strong westerly jet. However, in the context of global warming, the Arctic region is warming two to three times faster than the world. Liu Yunyun said that the temperature difference between the Arctic region and the middle and low latitudes has weakened, and it is difficult to maintain a strong westerly jet, and the cold air in the polar vortex has become "restless" and easier to move south. The cold air from the Arctic is much lower than the middle and low latitudes where we live, and the repeated cold waves make the public feel "quick-frozen".
At present, it is already cold before the "number nine", will the "three nines" and "four nines" be colder?According to the climate communiqué released by the National Climate Center, it is expected that in January 2024, the temperature in northeast Inner Mongolia, most of Heilongjiang, southwest Sichuan, western Yunnan, and southwestern Qinghai will be 05 to 1 Except for the rest of the country, the temperature in most of the rest of the country is close to the same period of the year to high. (ENDS).