"Didn't you say that the good ones are the warmest years? Why does the cold wave become cold as soon as it comes? "The recent cold has made people wonder. It's as if the warm spring has suddenly been replaced by the cold winter, and one can't help but sigh at the vagaries of nature. Like a naughty child, nature's changing face always catches people off guard. Perhaps, this is the charm of nature, which always brings us surprises and surprises inadvertently.
Under the influence of the westerly jet stream in the Northern Hemisphere, this cold air swept across the entire Northern Hemisphere like a huge force. It brought cold air, blizzards and freezing weather that forced people in the northern hemisphere to wear heavy clothing and hide indoors in the warmth.
The westerly jet stream acts like an invisible "fence" that tightly binds the cold air of the polar regions. Whenever the cold air tries to move south or north, this "fence" will block it back, ensuring that the cold air from the polar regions does not easily escape to other regions.
Therefore, even in the context of global warming, the cold air in autumn and winter is still so strong. This is because the large temperature difference between the equator and the polar regions and the westerly jet stream work together to allow cold air to continue to accumulate and move near the poles.
The Arctic region is warming 2-3 times faster than the global rate, as if it is a volcano about to erupt, and the temperature in the Arctic region has been rising in the context of global warming. Due to the weakening of the temperature difference between the middle and low latitudes and the Arctic, the strong westerly jet stream is like a card that has lost its support, and it is difficult to maintain its original stability. This makes the cold air in the polar vortex like a group of enraged beasts, becoming "restless" and making it easier to ** go south.
This phenomenon not only affects the ecological environment of the Arctic region, but also has a profound impact on the global climate. The melting of glaciers and permafrost in the Arctic is releasing large amounts of greenhouse gases, further exacerbating the rate of global warming. At the same time, the southward movement of cold air in the polar vortex will also lead to more extreme weather in the middle and low latitudes, such as more frequent storms, droughts and cold waves.
Since mid-December this year, the Arctic vortex has been like an actor in a drama, with two centers, located over Greenland and Siberia. With the violent distortion of the westerly wind belt over Eurasia, the Siberian high has strengthened abnormally, and most parts of China have changed from the prevailing southerly wind to the northerly wind in the early stage, and the cold air has moved southward, like a messenger of cold winter, bringing a sudden drop in temperature.
Although the global warming is higher than the average, the intensity of extreme cold waves has not weakened, and the impact range of strong cold air or cold waves has increased. For example, from February 14 to 17, 2020, the nationwide cold wave process affected China, and most areas experienced a cooling of 8 to 12, and even more than 18 in some areas; Snowfall (rain) occurred in Northeast China, eastern North China, Huanghuai and other places, and the maximum snow depth exceeded 40 cm at 7 stations in Jilin Province; Heavy rain or torrential rain occurred in Guangdong, Guangxi and other places, and many provinces experienced hail, strong winds, thunder and lightning, road ice and other disastrous weather. From January 20 to 25, 2016, strong cold air affected most parts of the country from north to south; The area of the national process cooling of more than 6 reached 7.86 million square kilometers, the process of 529 counties and cities was cooled by more than 12, and the temperature of 16 counties and cities was more than 18. The continuous cooling range of 23 stations exceeded the historical extreme, and the daily minimum temperature of 67 counties and cities exceeded the historical extreme. On the 25th, the first snowfall since the founding of the People's Republic of China occurred in Guangzhou.