On the 21st, the entire surface of Yunjin Lake on the bank of the Xiaoqing River froze over, and the ice layer was more than 3 centimeters thick, and it was as clear as jade when viewed from a high altitude.
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.
Didn't this year be the warmest year before?Why is it so cold when the cold wave comes?
Why is it so cold when the cold wave comes?
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.
The National Climate Center previously predicted that the average temperature in the country this autumn will be the highest in the same period in history,** and the results also show that the temperature in most areas this winter is close to normal or high.
When the cold wave comes, it is so cold, why does the public feel different from **?
The National Climate Center replied that when talking about the warmth of a certain year or month, it is not determined by a single weather event, but by comparing the average temperature of the entire period of time, whether it is significantly higher or lower than the same period in history. For example, from November 3 to 7 this autumn, there was a cold wave weather process in most parts of China, during which the temperature fell off a cliff, much lower than the same period in history, but if you calculate the average temperature of the whole autumn, it is the highest since 1961, so it is the "warmest autumn".
Why is the cold air still so strong due to global warming?
To put it simply, global warming will lead to a warming of the Arctic, a weakening of the westerly jet stream, a weakening of the polar vortex**, and an easier flow of cold air southward, which will lead to frequent cold events such as cold waves.
There is a huge temperature difference between the equator and the polar regions, and this difference has caused a strong westerly wind to form around the polar regions around the polar regions, which is called the westerly jet stream. The westerly jet stream acts like a "fence" that restricts the cold air from the polar regions. The stable polar vortex is confined to the Arctic region by a strong westerly jet stream, which is warming 2-3 times faster than the global rate in the context of global warming. As the Arctic warms and the temperature difference between the Arctic and the mid- and low-latitude latitudes weakens, it is difficult to maintain a strong westerly jet, and the cold air in the polar vortex becomes "restless" and more likely to move south. The cold air from the Arctic is much cooler than in the middle and low latitudes where we live, and the resulting cold spells make us feel very cold.
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.
However, 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 this year, the Arctic vortex** has been bicentric, located over Greenland and Siberia. With the violent distortion of the westerly wind belt over Eurasia, the Siberian high has strengthened abnormally, and most areas of China have 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, the El Niño-induced anomalous anticyclone in the Philippines transported tropical water vapor to China, so the cold wave 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. In addition, the increase in albedo in clear skies caused by snow on the ground also made the temperature recovery slower in the later period.
It is worth noting that China is a climate change sensitive area and a significant impact area, although the warming rate is higher than the global average, the intensity of extreme cold waves has not weakened, and the impact range of strong cold air or cold waves has increased.
Will the "three-nine" and "four-nine" be colder?
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.
The reporter learned from the National Climate Center that it is expected that the intensity of the East Asian winter monsoon in the latter winter (January-February 2024) will be generally weak, except for the northeast of Inner Mongolia, the north of Heilongjiang, most of the country, and the southern part of Qinghai The temperature is lower than that of the same period in normal years, the temperature in most parts of China is close to normal, but the cold and warm fluctuations are obvious, or the temperature "roller coaster" will be experienced again.
In the latter winter, the precipitation in the central and eastern parts of China is more, and the precipitation in the rest of the country is close to the same period of the year to less. The cold air activity is relatively active, and there may be a phased strong cooling and heavy snowfall process in the northern region, and there may be a phased low temperature rain, snow and freezing weather in the southern part of the Yangtze River and the eastern part of the southwest region. During the intermittent period of cold air, atmospheric diffusion conditions deteriorate, and fog and haze may occur in the Beijing-Tianjin-Hebei region and its surroundings, the Fenwei Plain and the Yangtze River Delta.