Is the continued cold temperature due to "late spring cold"? This article explains it to you

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Compiled by New Media Editor Lai Tianying

After the Spring Festival, the north continued to remain cold. Recently, a wave of cold waves in the south also caught people off guard. For example, the temperature in many places in southern provinces such as Guangdong and Yunnan dropped sharply, and snowflakes flew everywhere.

(Photo source: China Southern Power Grid WeChat)

▲The temperature in Guangdong dropped sharply, and the news that a cow was frozen to death became a hot topic (Source: Weibo Video Account - Ai Yangjiang)

▲Due to the cold weather, some people use quilts to keep warm (Source: Weibo Video Account - Express Video)

So, why has snowfall occurred in many places in the south recently?

Ma Xuekuan, chief forecaster of the Central Meteorological Observatory, explained that most precipitation processes are caused by the interaction between cold and warm air, and this time is no exception. Specifically, due to the continuous influence of cold air in the south in the early stage, the near-ground temperature dropped significantly, forming a "cold pad". Above the cold pad, the eastward movement of the southern branch trough caused the development of low-altitude warm and humid air currents, and the air currents rose when passing through the cold pad to form precipitation. The lower temperature near the ground is conducive to the occurrence of solid precipitation such as snow or sleet. Due to the good water vapor and dynamic conditions, the snowfall is generally large, and some areas can reach the level of blizzards and heavy blizzards.

It happens to be the time of season change, and many people associate this cold weather with "late spring cold".

(Source: Screenshot from Sina Weibo)

Experts from the Yunnan Provincial Meteorological Bureau remind that spring temperature drops are not necessarily "late spring cold". So, what is "late spring cold"? What are the hazards?

▲When cold air hits in spring, is it necessarily a "late spring cold snap"? (Source: Weibo client - Urban Barcode)

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What is “late spring cold”?

Among the four seasons, spring is the season with the most unpredictable changes in meteorological elements such as temperature, air flow, and air pressure. It is often sunny during the day, giving people a feeling of "the warm wind makes tourists intoxicated", but it is cold in the morning and evening, making people feel "the spring chill". Is this "changeable" weather that makes people difficult to adapt to what is usually called "late spring cold"?

In fact, if we understand "late spring cold" literally, it means that after the beginning of spring, the weather has not warmed up as expected, and the temperature has even dropped. Many people think that this is probably "late spring cold". But in fact, this understanding is not accurate.

(Source: China Meteorological Administration WeChat)

The term "late spring cold" originated from agriculture. It mainly refers to the fact that after entering spring, the temperature begins to rise and the average temperature reaches above 10℃. Due to the attack of strong cold air, the temperature drops rapidly and lasts for more than 1 to 2 weeks. From an overall perspective, it presents the phenomenon of "warm in the early spring and cold in the late spring".

From a time perspective, it often refers to the phenomenon that the temperature starts to rise after the spring equinox in March, and then drops sharply in April and May. Therefore, it is not accurate to say that the temperature drop after the beginning of spring is called "late spring cold".

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How is “late spring cold” determined?

The meteorological department has specific standards for "late spring cold". The meteorological bureau uses the annual comparison of low temperature intensity and average temperature to determine whether it is a "late spring cold". For example, the standard for judging "late spring cold" in February is: the sliding daily average temperature for 4 consecutive days is lower than the monthly average temperature by more than 5℃, or the daily minimum temperature on a certain day is lower than the monthly average minimum temperature by more than 5.9℃. If one of the above conditions is met, it can only be regarded as a general "late spring cold"; if both conditions are met, it can be regarded as a strong "late spring cold".

(Source: China Meteorological Administration WeChat)

Why does the weather change so much in spring? In fact, this is not difficult to explain. Spring is fickle. Early spring is a season transition period. At this time, the cold air is still unwilling to leave, and the warm and humid air flow gradually becomes stronger. At this time, the two are evenly matched, and they will fight to the death. If the cold air is stronger, the temperature will naturally drop, and the warm and humid air will fight back, and the temperature will rise again. Like the recent severe convective weather in Yunnan and Guangzhou, we know that this is another fierce "fire fight" between cold and warm air. At present, the "late spring cold" in most parts of my country mainly occurs in March to April every spring. The south warms up quickly and enters spring earlier, so the "late spring cold" naturally occurs earlier.

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What are the dangers of “late spring cold”?

First, the "late spring cold" can trigger cardiovascular and cerebrovascular diseases. The elderly have poor thermal balance and their circulatory system is easily stimulated by the "late spring cold". After the sympathetic nerves are stimulated by the cold, their excitement increases, and the capillaries on the surface of the skin contract, increasing blood flow resistance and causing blood pressure to rise. Since the elderly and patients with cardiovascular and cerebrovascular diseases cannot adapt to this change, cardiovascular and cerebrovascular diseases may occur.

Secondly, in early spring, some young girls who love beauty wear colorful skirts early. However, women's knee joints are more sensitive to cold air stimulation. After being attacked by cold air, local joints are prone to numbness, soreness and other symptoms. Over time, rheumatoid arthritis is prone to occur.

In addition, respiratory infectious diseases are prone to spread. The warm temperature before the late spring cold provides a breeding environment for respiratory pathogenic microorganisms. Once the temperature suddenly drops, the local temperature of the respiratory tract also drops, the body's resistance is weakened, and viruses or bacteria can easily invade. At the same time, the viruses and bacteria that originally parasitized in the respiratory tract will also take the opportunity to cause trouble, which will lead to the onset of respiratory diseases such as bronchitis.

(Source: China Meteorological Administration WeChat)

The population mobility is greater in spring, which also increases the chance of contact infection. In addition, the increase in recreational activities, irregular work and rest, physical fatigue, decreased resistance, cold and excessive fatigue can correspondingly weaken the physiological defense function of the respiratory tract. At this time, it is easier to suffer from diseases such as influenza, measles, chickenpox, rubella, mumps and meningitis.

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How to strengthen health protection when “late spring cold” comes?

It is necessary to keep warm in spring and not take off your winter clothes immediately because the temperature rises temporarily. The temperature is lower in the morning and evening, so you should pay attention to keeping warm and beware of colds and respiratory diseases.

It is necessary to ensure timely dust removal and ventilation in the room to reduce and inhibit the survival and reproduction of pathogens.

It is necessary to engage in appropriate outdoor activities to improve cardiopulmonary function and enable the body to better regulate and adapt to the changeable climate in spring.

▲ Outdoor sports in winter (Source: Xinhua News Agency)

Eat more foods that strengthen the spleen and stomach, such as chicken, duck, lean meat, eggs, vegetables, fruits, etc., which are rich in vitamins and trace elements and easy to digest. It helps to increase the body's immunity.

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How can special groups prevent “late spring cold”?

Studies have shown that during the "late spring cold" period, the incidence of hypertension, arteriosclerosis, stroke, angina pectoris and myocardial infarction among the elderly will increase significantly.

In addition, patients with chronic diseases such as peptic ulcers and chronic back and leg pain may also suffer relapses or worsening of old diseases due to climate change. Therefore, "late spring cold" poses a greater threat to the health of elderly people with chronic diseases and should not be taken lightly.

▲Disease prevention campaign for the elderly (Source: Sohu.com)

When the temperature drops suddenly, the elderly should add more clothes to keep warm, especially to keep sensitive parts such as hands, face (mouth and nose), etc. They should strengthen physical exercise to improve their physical fitness.

Pay attention to rest and keep your emotions stable. Avoid excessive fatigue and tension mentally and physically. Keep doors and windows open to allow sufficient sunlight and fresh air to flow indoors, which is beneficial for disease prevention and health care. Avoid smoking and drinking and eat a low-salt diet.

Here, I want to tell you that research by my country's Meteorological Bureau shows that starting today, the precipitation range in the south will shrink rapidly, the sun is expected to "show up" in many places, the temperature will gradually rise, and the highest temperature in most parts of South China will rise to double digits, and we will gradually usher in sunny days.

(The content of this article is compiled from Xinhua News Agency, China Meteorological Administration, Sohu.com, Sina Finance, 360 Common Sense Network)

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Produced by: Beijing Science and Technology News | Beijing Science and Technology Media

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