How do humans achieve artificial rainfall? What are the methods? What is the principle?

Mechanism of artificial rainfall.

Whether clouds in the sky rain or not depends not only on the amount of water vapor in the clouds, but also on the amount of condensation nuclei in the clouds. The mechanism of artificial rainfall, that is, the working principle, is to disperse catalysts to increase the number of condensation nuclei in the clouds, change the temperature in the clouds, disturb and produce convection through certain means, so as to achieve the purpose of rainfall in the medium and low cloud systems with relatively large cloud thickness.

Favorable meteorological conditions for artificial rainfall.

The generation of general natural precipitation not only requires certain macro weather conditions, but also needs to meet the microphysical conditions in the clouds, for example, there must be large water droplets in warm clouds above 0; There should be ice crystals in cold clouds below 0. If the necessary physical conditions are not met, no matter how good the weather situation is, no matter how good the cloud conditions are, it will not rain. Therefore, artificial rainfall is selected when the cloud and precipitation process is in the development or continuous stage, and the weather systems suitable for artificial precipitation enhancement mainly include cold front weather, northeast cold vortex and shear line.

At this time, the cloud layer is thicker, there is continuous updraft, and the cloud base is low, there is supercold water, and the concentration of ice crystal number is low, which is conducive to artificial rain enhancement operations.

How artificial rainfall works.

The core technology of artificial rainfall is to exert a catalytic effect on local atmospheric clouds through special airplanes, artillery, rockets and other means of transmission, so as to promote more moisture in the clouds to fall into raindrops. Currently, there are generally three types of catalysts used in artificial rainfall operations.

The first is dry ice. The temperature of dry ice is below zero, and when it vaporizes, the surrounding air layer can be cooled to about minus 40 degrees, thereby causing the condensation of water vapor, this way is called artificial cold cloud rainfall, the key is to make a sufficient number of ice crystals in the cloud, when the cloud ice crystals and water droplets (sub-zero and not frozen supercooled water droplets) exist at the same time, the water in the water droplets will automatically evaporate and condense onto the ice crystals, so that the ice crystals continue to grow into snowflakes, and the snowflakes then melt into water droplets and fall to the ground.

The second is silver iodide, lead iodide, ferrous sulfide, etc., which are called "nucleating agents". They have the properties of natural ice cores in the clouds. The reason why warm clouds that do not rain do not rain is mainly because the water droplets in the clouds are too small, do not grow big, and cannot fall.

Therefore, the key to artificial rain enhancement in warm clouds is to sprinkle the above-mentioned fine powder into the clouds, which is equivalent to increasing the number of condensation nuclei and interfering with the airflow in the clouds, which is conducive to the increase of small water droplets, changing the buoyancy balance, and when the updraft can no longer withstand the gravity of the water droplets, rainfall is formed.

The third is hygroscopic agents. Commonly used urea, ammonium nitrate, calcium chloride, etc., they can adsorb water in the cloud, and then form salt particles of larger water droplets, their corrosive effect is very small, and they are fertilizers for crop growth, so they are also effective and practical warm cloud artificial rain enhancement catalysts.

In addition, with the development of science and technology, there are many new ways of artificial rainfall, such as high-voltage technology (the principle is to produce plasma), electrocatalysis (mainly used for artificial rainfall to eliminate haze) and bacterial technology, but the three traditional methods just mentioned are more widely used.

Rainfall can be carried out through high-voltage technology, through electrocatalysis, through bacterial technology, mainly by the method of raindrop condensation.

Through the means of transmission of special airplanes and artillery rockets, human beings catalyze the local atmosphere between the clouds, thus causing the water in Britain and China to fall into raindrops.

The method is to use dry ice, or silver iodide, hydrogen iodide, ferrous iodide, and diluent as our company's artificial rain enhancement catalyst.

The principle is to disperse the catalyst in the medium and low cloud system with relatively large cloud thickness by certain means, increase the number of condensation nuclei in the cloud, change the temperature in the cloud, disturb and produce convection, so as to achieve the purpose of rainfall.

Generally, some dry ice will be sprayed on the clouds, and after the dry ice enters the clouds, it becomes gas, emitting some heat, and the temperature becomes lower and lower, and it will become a state of water droplets.

Artificial rainfall is mainly caused by artificially injected dry ice.

Artificial rainfallArtificial rainfall is very similar to natural rainfall in that it relies on water vapor condensing in clouds and eventually falling. It's still artificial rainfall, but it's one more step than natural rainfall, which is to add a catalyst to the clouds and let them gather together to form a rainfall phenomenon. Artificial rainfall naturally needs water, and there must be water-rich clouds at a certain height; Second, the temperature needs to plummet so that the water in the clouds condenses into rain.

Artificial rainfall simply takes away a lot of heat instantaneously when dry ice sublimates, lowering the ambient temperature and turning the clouds into rain.

The principle of artificial rainfall is to use certain means to spread catalysts for experiments, so as to increase the number of condensation nuclei in the cloud, change the temperature in the cloud, disturb and produce convection, so as to achieve the purpose of rainfall. In general, natural precipitation requires not only some macro-weather conditions, but also micro-physical conditions in the clouds. For example, there must be large water droplets in warm clouds above zero; The ice crystals must be in a cold cloud below freezing.

If the necessary natural conditions cannot be met, it will not rain regardless of the weather and cloud conditions. Therefore, artificial rainfall is chosen when the cloud and precipitation processes are in the developing or persistent phase. According to the experience of scientists, the weather systems suitable for artificial precipitation enhancement are mainly cold front weather, northeast cold vortex and shear line.

At this time, the clouds are thicker and there is a continuous rising airflow, which is conducive to artificial rain enhancement and artificial rainfall. The main technology of rainfall is to catalyze local atmospheric clouds through special transmission means such as aircraft, artillery, and rockets, so that more water in the clouds becomes raindrops.

Artificial rainfall is costly, even a complete waste of resources and a loss-making business. However, this is also a helpless situation. After all, it would be better if it could be solved with money than a drought.

It is understood that artificial rain enhancement has been implemented in Shanghai, China, and the cost has reached 4.7 million yuan at that time. The catalyst required for rainfall accounts for nearly 1 10 of the cost. Good steel is used on a knife edge, and in the arid-stricken agricultural provinces, the cost is terrible.

Of course, crops are very important. Therefore, China has been a small-scale peasant economy since ancient times, and now it tends to the common development of various economies, but agriculture still occupies an important part. In other words, if the crops die, what should the Chinese eat?

Therefore, no matter how you burn money, artificial rain should still be done!

Artificial rainfall is to change the number of condensation nuclei in the cloud, so that the water vapor particles strengthen the collision, and then rain, the principle is to use dry ice to release dry ice bombs into the sky, after the explosion is hot, the water vaporization will rain.

Artificial rainfall is achieved by rapidly lowering the temperature in the sky and causing the rapid condensation of water vapor, using catalysts such as dry ice, salt powder, and silver iodide into the clouds to cause precipitation.

It is like spreading a rainfall agent in a cloud, so that through chemical composition, rain can be carried out, and the cloud droplets increase to a certain extent, and finally fall to the ground, forming rainfall.

Artificial rainfall mainly uses dry ice, which is evaporated and then turned into water vapor to achieve the effect of rain.

Artificial rainfall mainly uses the principles of cloud and precipitation physics to promote cloud precipitation or increase precipitation by spreading rainfall agents such as salt powder, dry ice, silver iodide and other rainfall agents into the clouds.

Artificial rainfall is divided into two types: warm cloud rainfall and cold cloud rainfall, and in order to make warm clouds (clouds with temperatures higher than zero) rain or increase rainfall, it is necessary to spread hygroscopic particles such as salt powder and urea in the clouds to promote the formation of large raindrops for rainfall.

If cold clouds (clouds with temperatures below freezing) are to rain, they need to use airplanes and other tools to scatter rainfall agents such as dry ice and silver iodide, which will produce a large number of ice crystals, which will increase the density of ice crystals in the upper part of the cold cloud and promote the formation of rainfall.

Principle: Artificial rainfall uses the physical principles of clouds and precipitation to spread rainfall agents (salt powder, dry ice or silver iodide, etc.) into the clouds to increase the cloud droplets or ice crystals to a certain extent, and then fall to the ground to form precipitation. To put it simply, it is to condense water droplets into rain through artificial intervention, which is the principle of artificial rainfall, which is essentially a supplement to the necessary conditions for rainfall in nature.

Artificial rainfall conditions:

There are two conditions for the formation of precipitation, one is to have sufficient water vapor in the clouds, and the other is to have an appropriate number of condensation nuclei. Therefore, the method of artificial rainfall is to introduce artificial condensation nuclei into the clouds. Catalysts are generally sent into the clouds by means of aircraft, rockets, anti-aircraft guns, balloons, and burning silver iodide on the ground in updrafts.

Hygroscopic substances such as salt powder, urea, calcium chloride, etc., are generally used for warm clouds with a temperature above zero, so that the water vapor in the clouds turns into large water droplets and falls into rain. For cold clouds with temperatures below freezing, artificial crystal nuclei such as silver iodide or dry ice and liquid nitrogen are sown to increase the number of ice crystals in the cold clouds and improve the precipitation efficiency.

What exactly is the principle of "artificial rainfall"? Today, I have grown knowledge, and it turns out that it has such a big effect!

Using the principles of cloud and precipitation physics, by sprinkling rainfall agents (salt powder, dry ice (solid carbon dioxide) or silver iodide, etc.) into the clouds, the cloud droplets or ice crystals increase to a certain extent, and fall to the ground to form precipitation, also known as artificial precipitation. Methods of spreading include aircraft scattering in the clouds, anti-aircraft guns or rockets shooting silver iodide shells into the clouds**, and burning silver iodide flames on the ground. It is the most widely conducted weather modification experiment.

The microphysical process of artificially influencing clouds can make clouds that could not precipitate naturally under certain conditions be stimulated and precipitated, and can also make those clouds with more water and often able to precipitate naturally, improve the precipitation efficiency and increase the amount of precipitation. However, clouds that cannot be naturally precipitated have less water, so the economic value of artificial catalysis is limited.

The scientific principles of artificial rainfall.

Clouds are formed by the condensation of water vapor; The thickness and height of the cloud are usually determined by the amount of water vapor in the cloud, the number of condensation nuclei, and the temperature in the cloud. Generally speaking, the gelatinous state of water vapor in clouds is relatively stable and not easy to produce precipitation, and artificial precipitation enhancement is to destroy this gelatinous stable state. Usually artificial rainfall is to spread the catalyst (silver iodide) in the medium and low cloud systems with relatively large cloud thickness through certain means, so as to achieve the purpose of rainfall.

First, increasing the number of condensation nuclei in the cloud is conducive to the collision and increase of water vapor particles. The second is to change the temperature in the clouds, which favors disturbance and produces convection. The disturbance and convection in the clouds will be more conducive to the collision and increase of water vapor, and when the updraft in the air cannot withstand the floating of water vapor particles, rainfall will occur.

Formation of rainfall.

In the cloud block, with the continuous replenishment of water vapor in the air, the supersaturated water vapor continues to condense and condense on the cloud droplets, so that the cloud droplets continue to increase, when increasing to a certain extent, due to gravity, the cloud droplets begin to fall, in the process of falling, the large cloud droplets fall fast, and the small cloud droplets fall slowly, so the large cloud droplets will catch up with the small cloud droplets, merge into larger cloud droplets, and so on, the cloud droplets will gather bigger and bigger like a snowball, and finally fall to the ground and become raindrops.

On a clear summer day, when there is warmth and humidity in an area, convective motion occurs. Warm, moist air currents rise from the ground and condense into clouds as the insulation reaches supersaturation. In places where the downdraft is controlled, the air is adiabatic and warmed, and the relative temperature of the air is small, and clouds cannot be generated, so a light cumulus cloud with a convex top and a flat bottom like a steamed bun is formed, and if the convection continues to develop, because the middle part of the updraft is stronger than the surroundings, it will form Cumulus congestus like mountains or pagodas and Cumulonimbus clouds that are even larger like towering mountains.

Silver iodide has three crystal shapes, among which the hexagonal crystal shape is similar to the structure of ice crystals, which can play the role of ice nucleus, and is suitable for cold cloud catalysis of -4—-15. The number of ice crystals that can be produced per gram of silver iodide depends on the temperature, and the lower the temperature, the higher the number of effective ice cores, and the higher the number of ice crystals produced. For example, one gram of silver iodide can produce 1010-1012 ice cores at t=-10, and 1016 ice cores when t=-20.

The mechanism of silver iodide ice formation has been debated for many years, and some people believe that water vapor molecules directly condense on the AGI particle to form ice crystals, and silver iodide plays the role of a decotinate nucleus. It is also believed that silver iodide acts as a freezing nucleus, starting with the silver iodide dots as condensation nuclei to form water droplets, and then freezing to produce ice crystals. It is also believed that silver iodide acts as a contact nucleus, that is, silver iodide particles collide with supercooled water droplets and freeze to form ice crystals.

Some cloud workers have put forward the following view: the supersaturation of water vapor in nature is generally less than 1, and when the temperature is lower than -12, the ice-forming mechanism of silver iodide particles is mainly condensation. When the temperature is -12--5, it mainly plays the role of condensation and then freezing.

When the temperature is equal to -5, it plays a more obvious role in contacting the nucleus.

What exactly is the principle of "artificial rainfall"? Today, I have grown knowledge, and it turns out that it has such a big effect!