What is a cold wave?
Cold wave is a natural weather phenomenon. It refers to the cold air coming from high latitudes that rapidly intensifies under specific weather conditions and invades mid- and low-latitudes, causing severe cooling, strong winds, rain and snow on a large scale in areas along the way. This kind of cold air that reaches a certain level when it invades south is called a cold wave.
Cold wave is the cold air from the polar regions or frigid zones in the winter half of the year, which invades middle and low latitudes on a large scale like a tide. When a cold wave hits, it will cause a sharp drop in temperature, 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 everything is covered with ice and snow. The air masses staying in those areas are getting colder and drier. When this cold air mass accumulates to a certain extent, the air pressure increases to When it is much higher than the south, it is like floods stored in high mountains. Whenever there is an opportunity, it overflows and pours to the south where the air pressure is lower, which forms a cold wave.
In winter and spring, cold wave and strong winds often cause great impact and disasters on crops and people's production and life. To prevent strong wind disasters, we should mainly do the following:
Attach great importance to it
Do all the defense work in a timely manner. All localities and relevant departments should attach great importance to immediate action, take effective response measures, and organize defense work in a timely and responsible manner. At the same time, news media, e-commerce, mobile phone text messages, etc. should be used to quickly release the weather change process and related information and defensive measures to the society, so that the general public and relevant units can carry out defense work in a timely manner.
Take measures
to ensure the safety of agricultural production. All counties (cities, districts) and municipal agricultural bureaus should organize agricultural technicians to go to the front line to actively guide and help the masses to take various preventive and remedial measures to minimize disaster losses. With facility agriculture as the focus of defense, we must carefully carry out defense work such as reinforcing the shed body, compressing the shed film, and insulating against freezing. Strengthen the reinforcement of pens, immunize livestock and poultry, etc., keep young livestock warm, improve the ability of livestock and poultry to resist cold and disease, and ensure the safety of livestock and poultry.
Take immediate action
Practice other aspects of work well. All localities and relevant departments must act quickly, clarify responsibilities, implement tasks, and carefully investigate key areas such as construction sites, outdoor advertising, power facilities, urban and rural dilapidated buildings that may be affected by strong winds, and prevent possible problems in advance and take strong measures. measures to ensure the safety of people's lives and property.
Traffic Safety
Strong winds have a greater impact on the operation of sea, land and air transportation. Personnel engaged in offshore operations should stop operations, return to the port to take shelter, Measures such as reinforcing ships and drilling platforms; strengthening dynamic supervision of ships, conducting on-site patrols and on-site inspections; paying close attention to weather changes, strictly implementing regulations on wind resistance levels, and strictly prohibiting risky sailing beyond wind resistance levels. Strengthen duty, maintain regular lookout, and drive cautiously; strengthen ship-shore linkage, and the company's main management personnel can actively, proactively and comprehensively grasp the status of the ship, and eliminate potential unsafe factors in a timely manner. In the case of strong winds, airports and highways should be closed, and passenger trains should also be suspended under special circumstances to prevent traffic accidents caused by strong winds.
Variety cultivation
Plant freezing damage occurs when overwintering crops and fruit trees are frozen when strong cold air breaks out southward and produces severe cooling, causing plant death or partial death. Therefore, on the one hand, preventing frost damage It is necessary to try to improve the ability of overwintering crops and economic fruit trees to withstand low temperatures. On the other hand, measures should be taken to block the invasion of cold wind and reduce the intensity of cooling. Effective measures to prevent frost damage mainly include:
Cultivation of cold-tolerant varieties to improve frost resistance
For overwintering crops or subtropical economic fruit trees, select and breed cold-tolerant varieties to improve plant frost resistance. Ability is a strategic measure to avoid or mitigate freezing damage.
Pre-winter management
Strengthen pre-winter management and enhance frost resistance
The quality of cultivation and management directly affects the frost resistance of overwintering crops and fruit trees. Therefore, good pre-winter cultivation management is an important measure to prevent cold wave damage.
Utilize the environment
Use the local microclimate environment and avoid freezing in real time for cultivation
In the northern edge of China's subtropical citrus cultivation, make full use of the favorable conditions of mountains or water bodies Cultivating citrus in a microclimate resource environment can effectively avoid or reduce cold wave damage.
Notes
1. When the temperature drops sharply, be sure to add clothes to keep warm, especially your hands and face.
2. Close doors and windows and secure outdoor structures.
3. Be careful of slippery roads and falls when going out.
4. Elderly and weak patients, especially cardiovascular patients, asthma patients and other people who are sensitive to temperature changes should try not to go out.
5. Pay attention to rest and avoid excessive fatigue.
6. Families using coal stoves for heating should beware of gas poisoning.
7. Weather forecasts should be strengthened and accurate cold wave news or warnings should be issued in advance.
8. Publish accurate cold wave news or warnings to enable ships at sea to return in time.
9. Prepare crops, livestock, etc. for cold protection in advance.
Anti-freezing measures
In addition to the above-mentioned strategic measures to prevent freezing damage, a variety of anti-freezing and anti-freezing measures can also be adopted before the onset of low temperatures in winter and during the cooling period.
The government and relevant departments should do emergency and rescue work to prevent cold waves in accordance with their duties; pay attention to cold protection and warmth; agriculture, aquaculture, animal husbandry, etc. should actively take anti-frost, ice and other cold protection measures to minimize losses and do a good job in wind protection.
Open-air heating
Use all conditions to increase the temperature of the near-surface layer, such as laying out smoke piles, installing blowers, etc., to disrupt the inversion layer and have a significant warming effect on the near-surface layer. , among which fumigation can generally increase the near-surface temperature by 1~2°C.
Vegetation covering
Use covering to protect the above-ground or underground parts of plants that are afraid of freezing, reduce ground long-wave radiation, and prevent cold wind invasion, thereby preventing cold. There are two types of mulching: horizontal and vertical mulching. Some are directly mulched on crops or fruit trees, some are covered with sheds, and some are wrapped. Wind barriers are also effective in preventing freezing damage, and wind barrier designs of different types and angles can be adopted according to actual conditions.
Spraying chemicals
Mainly used to prevent frost on fruit trees. Spray chemicals to prevent frost damage. First, use growth hormone to control the growth pattern of fruit trees and enhance frost resistance. Chemical method to prevent freezing damage is an emergency measure, and short-term cold wave cooling forecast must be grasped.
In addition, after the cold wave occurs, some simple cold protection remedial measures can be taken for different crops. Such as prying mud to build soil and protecting roots, pressing grass to protect seedlings, etc. For spring potatoes and spring soybeans that sprout early, small sheds can be set up in time to protect them from the cold. After various crops are frozen, an appropriate amount of quick-acting nitrogen fertilizer and potassium fertilizer should be applied in a timely manner according to the degree of frost damage and seedling condition, and 3~5kg of urea and potassium chloride should be applied per acre (1/15hm2) to promote the plants to resume growth as soon as possible.
Benefits
Cold waves also have beneficial effects. Research and analysis by geographers show that cold waves contribute to heat exchange on the earth's surface. As the latitude increases, the solar radiation energy received by the earth gradually weakens, so the earth forms tropical, temperate and cold zones. The cold wave carries a large amount of cold air to the tropics, causing a large-scale exchange of ground heat, which is very helpful for maintaining the ecological balance of nature and maintaining the prosperity of species.
Meteorologists believe that the cold wave is the guarantee of good weather. For example, China is affected by the monsoon and has a dry climate in winter, which is the dry season. But whenever a cold wave invades the south, it often brings widespread rain and snow, which alleviates winter drought and benefits crops. Why has the agricultural proverb "Auspicious snow heralds a good harvest" been passed down among the people for thousands of years? This is because the nitrogen content in snow water is high, more than five times that of ordinary water, which can greatly increase the nitrogen in the soil. Snow water can also accelerate the decomposition of organic matter in the soil, thereby increasing the organic fertilizer in the soil. Heavy snow covers overwintering crops, acting like a quilt to resist cold and keep warm. There is a saying that "If it is not cold in winter, there will be no good harvest in the coming year." This also has its scientific truth. Experts on crop disease and pest control believe that the low temperature brought by the cold wave is currently the most effective natural "insecticide". It can kill a large number of pests and germs lurking in the soil for the winter, or inhibit their growth, reducing pests and diseases in the coming year. According to survey data from agricultural technology stations in various places, pesticides can be saved by more than 60% in years with heavy snowfall.
Cold waves can also bring wind resources. Scientists believe that wind is a pollution-free and valuable power resource. The world-famous Miyakojima Wind Power Station in Japan has a power generation efficiency that is 1.5 times that of normal times during cold waves.