What is the process of artificial snowfall?

There are two conditions that must be met for the water vapor in the sky to turn into rain and snow, one is that there must be a certain saturation of water vapor (mainly related to temperature), and the other is that there must be condensation nuclei. Therefore, artificial snowfall must first have clouds in the sky, and without clouds, it is like a clever woman who is difficult to cook without rice, and it cannot snow. Clouds that can snow, 0 or less"Cold clouds"。

In the cold clouds, there are both small water droplets condensed by water vapor and small snow crystals condensed by water vapor. But they are very small and light, and if there are no conditions for them to continue growing, they can only be suspended in the air like smoke and dust, and it is difficult to fall. In winter, we often see large clouds that do not see snowflakes falling, because the snow crystals that make up these clouds are too small to overcome the buoyancy of the air, and the precipitation capacity is very poor.

If some particulate matter is sprayed in the clouds, and the snow crystals grow so quickly that they can overcome the buoyancy of the air and fall down, this is the work of artificial snowfall.

What can be sprayed to cause snow crystals to grow quickly? In the early days, there were many interesting ways to do this. The main methods are:

arson on the ground and a large amount of smoke and dust into the sky; attacking the clouds with artillery; Use the kite to fly high in the clouds, and then electrify the kite, flash and discharge sparks; Fly into the clouds and spray liquid water droplets and dust particles. However, none of these methods worked well. It wasn't until 1946 that it was discovered that millions of snow crystals could be formed when very small particles of dry ice were thrown into cold clouds.

On January 3 of that year, someone sprinkled dry ice particles on top of an Altocumulus cloud with a temperature of -20 on an airplane, and snow was found falling from the cloud.

Dry ice is not frozen by water, but in a solid state of carbon dioxide, much like snow that is compacted in winter. The temperature of dry ice is very low, in the following. The dry ice crystals are sprayed into the cold cloud like a goddess scattering flowers, and each carbon dioxide crystal becomes a severe cooling center, causing the water vapor, small water droplets, and small snow crystals in the cold cloud to quickly gather around it, condensing into larger snowflakes and falling down.

How do you disperse these condensation nuclei into the clouds? Most modern people use cannons, which are loaded with chemicals in cannonballs and then fired into the clouds with cannons. However, this method is unevenly sprayed, and the waste of medicine is large, which increases the cost of artificial snowfall.

Others put them in dirt rockets and let them fly into the clouds and spray them.

How did "artificial snowfall" come about? After watching the whole process, I finally understood.

The difference between artificial snowfall and natural snowfall is that artificial snowfall is to spray some particulate matter, soot, dry ice, and silver iodide in the clouds through cannonballs, and then use cannons to launch them into the clouds, provided that there must be clouds in the sky, and artificial snow cannot fall without clouds. Natural snowfall is the crystallization of water and dust at low temperatures.

Formation of snowflakesIt is mainly related to water vapor in the air. When the winter temperature drops below 0, the water vapor in the air condenses into Xiaoice crystals in the clouds. Water vapor is formed when ice crystals in clouds collide with supercooled water droplets and evaporate.

As the water vapor condenses, it gradually increases in size and slowly turns into snowflakes. Since snowflakes are formed by the enlargement of ice crystals, and the molecules of ice crystals are mostly hexagonal, snowflakes are also mostly hexagonal.

Snow has a wide range of effects, but snow has great benefits for humans. First of all, it is conducive to the growth and development of crops. Because snow conducts heat very poorly, the soil surface is covered with a layer of snow cover, which can reduce the transfer of soil heat and block the invasion of cold air on the snow surface, so the crops protected by snow can safely overwinter.

Snow also stores water for crops. In addition, snow enhances soil fertility.

The purpose of artificial snowfall is to improve winter and springPrecipitation。Reducing the frost damage loss of overwintering crops, increasing water and soil vigor are conducive to the smooth progress of spring sowing. At the same time, the process of artificial snowfall is conducive to air purification, soil moisture improvement and forest fire danger level.

Winter and spring are the main times for artificial snowfall, and the need for artificial snowfall depends on the local water resources.

Composition of snowflakesIce clouds are made up of tiny ice crystals. When these Xiaoice crystals collide with each other, the surface of the ice crystals will heat up and melt somewhat, and they will stick to each other and freeze again. This is repeated many times, and the ice crystals increase.

In addition, there is also water vapor in the clouds, so the ice crystals can continue to grow by condensation.

However, ice clouds are generally very high and not thick, where there is not much water vapor, and the growth of condensation is very slow, and there are not many opportunities for collisions with each other, so they cannot grow to a large size and form precipitation. Even if precipitation is caused, it tends to evaporate on the way down and rarely reaches the ground.

Artificial snowfall stove refers to the artificial sprinkling of silver iodide particles in the clouds with poor precipitation ability, so that they can replace snow crystals, so that the water vapor and small water droplets in the clouds can crystallize on the silver iodide micro-particles and grains, and become snowflakes. The success rate of artificial shed snow removal is greater than that of artificial rainfall, which can increase rainfall by about 20%, while in alpine and cold areas, artificial snowfall can increase precipitation by 30%-40%.

The purpose of artificial snowfall is to increase the precipitation in winter and spring, reduce the frost damage loss of overwintering crops, increase water and soil vitality, and facilitate the smooth progress of spring sowing.

At the same time, the process of artificial snowfall is conducive to air purification, soil wall condition and forest fire danger reduction. Winter and spring are the main times for artificial snowfall, and the need for artificial snowfall is determined according to the local water situation. Silver iodide is often used for artificial snowfall.

Silver iodide is a yellow-colored chemical crystal, which is usually used as a photosensitive agent in lighting materials. The hexagonal monomers of silver iodide snow crystals are very similar in size, the atomic arrangement in their monomers is also very similar, and the lattice spacing between the two is also very similar (silver iodide is angstroms, snow crystals are angstroms). Therefore, snowfall missiles are used to scatter silver particles in clouds with poor precipitation ability, making it "impersonated.""Replacing snow crystals can cause the water vapor and small water droplets in the clouds to crystallize on the "impostor crystals" and turn into snowflakes.

Artificial snowmaking refers to the process of artificially turning water (water vapor) into snowflakes or snowflakes through certain equipment or physical and chemical means. Artificial snow manufacturing methods are divided into cannon barrel type and borneol crushing type. Natural snowflakes have a density of about 328 kilograms of cubic meters, while artificial snow has a density of about 856 kilograms of cubic meters.

Essentially, artificial snow and natural snow are the same, but artificial snow is denser. Therefore, under the same conditions, artificial snow of the same volume melts more slowly than natural snow. Compared to natural snow in nature, the shape of the snow produced by any form of snowmaking equipment cannot be similar to its shape, and it is impossible to achieve natural snow in the shape of a six-sided diamond.

According to the physical characteristics of clouds and the principle that rain and snow are formed by condensation of water vapor, airplanes, rockets, etc. are used to spray refrigerant into the clouds in the sky, so that the water vapor in the sky quickly condenses into water droplets, so that the small water droplets in the clouds increase and become larger, thus forming rain or snow. This kind of rain or snow falls under the condition of artificial intervention in weather changes, which can develop the potential precipitation resources in the cloud and increase the precipitation efficiency of the cloud, so it is called artificial rainfall or artificial snowfall.

Like dry ice thrown from high altitude, dry ice absorbs heat, causing the temperature to drop and snow to form.

Dry ice is used in the air to condense the water in the sky, and after that, the snowfall conditions are formed, and it snows. It's all snowed by airplanes

In addition to the thermal insulation and moisture retention effect of overwintering crops, the white snow also has a wonderful medicinal effect on the human body.

Studies have also shown that snow water contains more enzyme compounds than ordinary water, so it is generally believed in the medical community today that drinking 1-2 cups of snow water a day can significantly reduce blood cholesterol content and prevent and treat arteriosclerosis.

It can be seen that snow water is a sweet medicine given by nature to human beings. When people are snowing heavily in the cold winter, don't forget to sweep some fresh snow and save it for future treatment and drinking.