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Original title: Popular science | Is it very cold this winter? Why? What about the future – what the experts say
It’s a bit cold this winter!
Whether in the south or in the north,publicI feel the same about the “cold” since the beginning of winter. On December 23, there was another round of cold air in many parts of the country, causing the weather, which had just been warm for two days, to become colder again.
At the same time, news items such as “New Year’s Eve may find a big cold snap” appeared on the Internet, causing people to worry even more: Will the future be so cold? What caused this cold? Will production and life be more affected?
Experts from the Central Meteorological Observatory and the National Climate Center responded to the relevant issues one by one.
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You’re cold because it’s so cold!
Monitoring data from the Department of Meteorology shows that since December, temperatures in many parts of the country have been lower than in the same period in previous years.
Image source: National Climate Center.
It can be seen from the national average temperature anomaly map from December 1 to December 22 that, except for northeast Inner Mongolia, western and northern Heilongjiang, Tibet, most of Qinghai, western Sichuan and Yunnan , the temperature is higher than normal.The temperature in most areas of China is close to the same normal year period or lower, and the number of provinces accounts for about 80% of the country.Temperatures in North Xinjiang, North Northwest China, most of Inner Mongolia, North and West North China, Southeast Southwest China, West Jiangnan, and West South China2 to 4 low。
What is the concept of low temperature 2 to 4?ImagineFor a moment, compared to air-conditioned rooms at 26 in summer, the difference in body perception is still obvious compared to air-conditioned rooms at 24 and 22, and the same is true in winter. Not only that, the minimum of 2 to 4 is just an average state, and the local extremes are more serious.
Niu Ruoyun, head of medium-term weather forecast at the Central Meteorological Observatory, said that since December, the temperature in many places has fluctuated due to the influence of cold air forces. For example, from September 9 to 13, the average temperature in most of the country was slightly higher than in previous years. In such circumstances, when the cold air arrives, the audience will feel it more intensely.
Take Erlianhot, Inner Mongolia, for example. The city’s average temperature in the last 10 days was -22.5, which was 7.5 lower than usual. The lowest temperature on December 15 was -36.4, which was the extreme value for the same period in December since 1968. The 10-day average temperature of Tongliao Huolin Gol Meteorological Station reached -20.8, breaking the value. lower end (-20.5) of the station’s historical mean temperature during the same period. It is clear that the temperature is low and is affected by snowfall. Some grazing areas are very likely to form “in winter snow”, which is not good for foraging and hibernating livestock in grazing areas. At the same time, lambs and calves are prone to freezing to death. Old neighborhoods in urban areas are also facing an intense warming situation.
In Guiyang City, Guizhou Province, the temperature in the city in mid-December was generally 3.4 to 4.8 lower than normal. Especially during the low temperature snow condensation weather from 14 to 17, the minimum temperature in some cities and towns in Guiyang dropped to -6 (average temperature 0.7 to 3.5), the roads froze and the lines transmission were icy.
On December 16, the freezing weather continued in Guiyang City, Guizhou Province. As the temperature stayed below 0 and the night was often accompanied by freezing rain, the leaves and grasses in the highlands were covered by freezing rain.Photo / Text: Shi Kui Gao Civilization
From this point of view,It’s been cold since December, which is true in many areas.。
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Why is it so cold this year?
The lack of sea ice in La Niña and the Arctic is an important background to the cold, and the cold may continue into the future.
High or low temperature over a period of time belongs to the climatic category, which is mainly the result of the interaction of the atmosphere, ocean, land surface, ice and snow, and other spheres. If the sun warms the ocean and the sea temperature rises by 0.5, the warming and evaporation of sea water will affect atmospheric circulation. For our country, the temperature of the tropical sea, the sea ice of the Arctic and the snow in Europe and Asia are important factors that affect the winter climate.
Yuan Yuan, a researcher at the National Climate Center’s Office of Weather Prediction, believes thatThe main reason for the low temperature in many places since December is the “strong four”——In December, there was a strong southern circulation in the middle and high latitudes of Europe and Asia, the high-pressure ridge of the Urals was stronger and the broad depression of Lake Balkhash-Baikal was also stronger. The Upper Siberian was also obviously stronger in the pressure field at sea level. These are all favorable factors that cause cold air to affect China from north to south from the northwest. From a broad climatic context, the development of La Niña and the lack of anomalous sea ice in the Arctic are the two main external forcing factors.
In December, the upper-middle latitudes of Eurasia showed strong southern circulation, the Ural high-pressure range was stronger, and the wide low-pressure depression between Lake Balkhash and Lake Baikal was also stronger. image: National Climate Center.
the girl, Refers to the equatorial Middle EastThe Pacific OceanThe phenomenon of abnormally cold sea surface temperature continues in a wide range. “In most winters during the peak of La Niña, the mid-high latitude meridian of Eurasia is relatively large and cold air activity is also strong. It is likely that the temperature in most of the central parts and eastern China is low, “said Yuan Yuan.
This fall, the Arctic sea ice was unusually low. In September, Arctic sea ice was the second-lowest on record, and October and November were also the lowest on record and the second-lowest. “Less sea ice also favors the strong Ural mountain range in winter and the strong winter monsoon in East Asia. The temperature in most of central and eastern parts of China is likely to be lower than normal.” But Yuan Yuan also pointed out that, in the current context of global warming, the impact Factors of abnormal winter weather in China are more complicated. Specifically for a certain cold stage or a certain strong cooling process, it is mainly a direct result of abnormal atmospheric circulation. It is difficult to say which factor or several factors are responsible.
Currently, La Niña is still in a state of development, and the National Climate Center predicts that it may peak later this month, and the intensity may be moderate. There is little sea ice in the Arctic and it is not easy to change. Thus,In the short term, the overall colder temperature in China will continue.
Cold air can “New Year’s Eve”, so we must prevent the adverse effects of low temperatures.
According to Niu Ruoyun, at the end of December this year, the force of cold air has increased significantly, and around the 30th, two cold airs will invade our country.
According to the latest medium-term forecast issued by the Central Meteorological Observatory, from 28-30, cold air will continue to move east and south, affecting most of the central and eastern regions of China. The temperature will drop 6 to 8 degrees. Until 10-12, and will be accompanied by 4-6 winds from the north, with gusts of up to 7-8; there will be light to moderate snow in Southeast Northwest China, South North China, Huanghuai and rain in Jianghan, Jianghuai and North Jiangnan. Sleet, light rain in central and southern Jiangnan, southern China, moderate rain locally.
Image source: National Climate Center.
Therefore, from the perspective of weather trends, it is not impossible to say that “cold air accompanies New Year’s Eve” that has spread the most, but the actual temperature should be subject to immediate forecasts.
It should be noted that the current trend forecast from 8 days to 15 days on the Internet is a medium-term forecast, which is a numerical forecast.productThe result obtained by direct analysis has not been corrected by the forecaster and is for reference only.
The numerical forecast itself is the future weather trend calculated based on the actual situation. The greater the punctuality, the greater the error. You should always be aware of the weather and take precautions.
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Tips
Beware of colds
The temperature is too cold and the public must protect themselves from all inconveniences caused by low temperatures. Winter is a period of high incidence of respiratory diseases and the mortality rate from respiratory diseases increases significantly. The low temperature environment is conducive to the survival and spread of the virus, after entering the winter, due to the low temperature, the body’s resistance will decrease and the susceptibility will increase. This winter cold air activities are more frequent and the temperature fluctuates a lot, it is necessary to take strict precautions to prevent colds and other diseases.
Beware of low temperatures, rain and snow.trafficPower and other influences
From the production perspective, in the last winter (January-February 2021) the north of Xinjiang, the west and northeast of Inner Mongolia, the center and east of northwest China, and the center and north of northeast China, may There will be periods of sharp drop in temperature and heavy snowfall. Snow disasters must be dealt with. And low temperature defensejobs. There may be periods of low temperature and freezing rain and snow in the eastern part of southwest China and the western part of Jiangnan. It is necessary to prevent its adverse effects on transportation, electricity and spring plowing.
(Source: Reading Chuang)
(Editor in charge: DF527)
I solemnly declare: The purpose of this information is to spread more information, and it has nothing to do with this booth.
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