Why is there a cold wave in winter?

Cold wave is a natural weather phenomenon. Refers to the cold air from high latitudes, which is rapidly strengthened in a specific weather situation and invades the middle and low latitudes, causing a wide range of severe cooling, strong winds and rain and snow weather along the way. When this cold air reaches a certain standard, it is called a cold wave.

Cold wave is cold air from polar regions or cold zones in winter, which invades the middle and low latitudes on a large scale like tides. When a cold wave strikes, the temperature will drop sharply, accompanied by strong winds, rain and snow. It has a serious impact on industrial and agricultural production, people's lives and human health.

There is no sunshine for a long time in winter, and there is snow and ice everywhere. The air masses staying in these areas are getting colder and drier. When this cold air mass accumulates to a certain extent and the air pressure in the south increases to a much higher level, it is like a flood stored on a mountain. Whenever there is an opportunity, it floods to the south where the air pressure is low, forming a cold wave.

In winter and spring, cold wave and windy weather often have great influence and disaster on crops and people's production and life. The defense of gale disaster mainly includes the following points:

pay high attention to

Do all kinds of defense work in time. All localities and relevant departments should attach great importance to it, take immediate action, take effective countermeasures, and organize defense work in a timely and responsible manner. At the same time, news media, e-commerce, mobile phone short messages, etc. It should be used to quickly release the weather change process and related news and defense measures to the society, so that the masses and relevant units can carry out defense work in time.

take measures

Ensure the safety of agricultural production. Counties (cities, districts) and the Municipal Bureau of Agriculture should organize agricultural technicians to go deep into the front line, actively guide and help the masses to take various defensive and remedial measures, and minimize disaster losses. Take facility agriculture as the defense focus, and do a good job in the defense work such as shed reinforcement, shed film compaction, warmth and antifreeze. Strengthen fence reinforcement and livestock immunization, keep young animals warm, improve the cold and disease resistance of livestock and poultry, and ensure safety.

make a move

Do well in other aspects. All localities and relevant departments should act quickly, clarify responsibilities, implement tasks, carefully investigate key parts such as construction sites, outdoor advertisements, power facilities, and dangerous houses in urban and rural areas that may be affected by strong winds, prevent possible problems in advance, and take effective measures to ensure the safety of people's lives and property.

driving safety

Strong winds have a great influence on the operation of sea, land and air traffic. Personnel engaged in offshore operations should take measures such as stopping operations, returning to Hong Kong to take shelter from the wind and strengthening ships and drilling platforms according to the weather forecast. Strengthen the dynamic supervision of ships and do a good job in on-site inspection and inspection; Pay close attention to the weather changes, strictly implement the provisions of the wind resistance level, and it is strictly forbidden to take risks beyond the wind resistance level. Strengthen duty, watch regularly and drive carefully; Strengthen the linkage between ship and shore, so that the main management personnel of the enterprise can take the initiative, actively and comprehensively grasp the situation of the ship and eliminate potential unsafe factors in time. In case of strong winds, airports and expressway should be closed, and under special circumstances, passenger trains should also be stopped to prevent traffic accidents caused by strong winds.

breed of variety

Plant freezing injury refers to the severe cooling of overwintering crops and fruit trees when strong cold air erupts southward, resulting in plant death or partial death. Therefore, on the one hand, efforts should be made to improve the ability of winter crops and economic fruit trees to resist low temperature, on the other hand, measures should be taken to prevent the invasion of cold wind and reduce the intensity of cooling. Effective measures to prevent frostbite mainly include:

Cultivate cold-resistant varieties and improve their frost resistance.

For overwintering crops or subtropical economic fruit trees, it is a strategic measure to cultivate varieties with strong cold tolerance and improve the frost resistance of plants.

Management before winter

Strengthen management before winter and enhance frost resistance.

The quality of cultivation management directly affects the frost resistance of overwintering crops and fruit trees. Doing cultivation management well before winter is an important measure to prevent cold wave freezing injury.

Use the environment

Real-time frost-free cultivation using local microclimate environment

In the northern edge of subtropical citrus planting in China, making full use of the favorable microclimate resources and environment in mountainous areas or water bodies to plant citrus can effectively avoid or alleviate the cold wave freezing injury.

Matters needing attention

1. When the temperature drops suddenly, pay attention to add clothes to keep warm, especially the hands and face.

2. Close the doors and windows and fix the outdoor structure.

Be careful when you go out.

4. The old, the weak, the sick and the disabled, especially those who are sensitive to temperature changes such as cardiovascular patients and asthma patients, should try not to go out.

5. Pay attention to rest and don't be overtired.

6. Families who use coal stoves for heating should beware of gas poisoning.

7. Weather forecast should be strengthened, and accurate cold wave news or warning should be released in advance.

8. Issue accurate cold wave news or alarm, so that ships at sea can return in time.

9. Prepare crops and herds for cold protection in advance.

Anti-freezing measures

In addition to the above-mentioned strategic measures, various cold and antifreeze measures can be taken before and during the low temperature in winter. The government and relevant departments shall, in accordance with their duties, do a good job in emergency rescue against cold waves; Pay attention to cold and warmth; Agriculture, aquaculture, animal husbandry, etc. Anti-freezing measures should be actively taken to minimize losses and do a good job of wind protection.

Open air heating

Disturbing the inversion layer by arranging smoke piles, installing blowers and other conditions to increase the near-surface temperature has a significant warming effect on the near-surface layer, in which smoking can generally increase the near-surface layer temperature by 65438 0 ~ 2℃.

Vegetation coverage

Covering is used to protect the above-ground or underground parts of plants that are afraid of freezing, reduce long-wave radiation on the ground, and defend against cold wind, thus playing a role in cold protection. There are two kinds of mulching: horizontal and vertical, including direct mulching on crops or fruit trees, scaffolding covering and wrapping. Windshield also has a good effect on preventing freezing injury, and different types of windshields with different inclination angles can be adopted according to the actual situation.

Spray medicine

Mainly used for anti-freezing of fruit trees. Spraying chemicals to prevent freezing injury, first, using growth hormone to control the growth law of fruit trees and enhance the cold resistance. Chemical methods to prevent freezing injury are emergency measures, and short-term cold wave cooling forecast must be mastered.

In addition, after the cold wave, some simple cold-proof remedial measures can be taken for different crops. Such as digging mud, cultivating soil to protect roots, pressing grass to protect seedlings, etc. For spring-sown potatoes and soybeans with early emergence, small arch sheds can be set up in time to prevent cold. After all kinds of crops are frozen, appropriate amount of quick-acting nitrogen fertilizer and potassium fertilizer should be applied in time according to the degree of freezing damage and seedling condition, and urea and potassium chloride 3-5 kg/mu (115hm2) should be applied to promote the plants to resume growth as soon as possible.

profit

Cold waves also have beneficial effects. The research and analysis of geographers show that the cold wave contributes to the heat exchange on the earth's surface. With the increase of latitude, the energy received by the earth from solar radiation gradually weakened, so the earth formed tropical, temperate and cold zones. The cold wave injects a lot of cold air into tropical areas, which makes large-scale heat exchange on the ground, which is very helpful to maintain the ecological balance of nature and maintain the lush species.

Meteorologists believe that the cold wave is the guarantee of good weather. For example, China is affected by the monsoon, and the winter climate is dry, which is a dry season. However, whenever the cold wave invades the south, it will often bring a wide range of rain and snow weather, alleviate the winter drought and benefit crops. Why can the agricultural proverb "Xue Ruizhao has a good year" be circulated among the people for generations? This is because snow water has a high nitrogen content, which is more than five times that of ordinary water, and can greatly increase the nitrogen in the soil. Snow water can also accelerate the decomposition of soil organic matter, thus increasing the organic fertilizer in the soil. The heavy snow covered the overwintering crops and played the role of a quilt, keeping out the cold and keeping warm. There is a saying that "it is not cold in winter and not rich in the coming year", which also has its scientific truth. Experts in crop pest control believe that the low temperature brought by the cold wave is the most effective natural "insecticide" at present, which can kill a large number of pests and germs lurking in the soil for the winter, or inhibit their breeding and reduce pests and diseases in the coming year. According to the survey data of agricultural technology stations around the country, pesticides can be saved by more than 60% in the year of heavy snow and winter closure.

Cold waves can also bring wind resources. Scientists believe that wind is a valuable energy source without pollution. The power generation efficiency of the world-famous Miyakojima wind power station during the cold wave is 1.5 times that of the usual one.