The reason why dry ice can be used for artificial rainfall

Dry ice is solid carbon dioxide, and gaseous carbon dioxide is formed by low temperature + pressure.

The principle is. Dry ice vaporizes when exposed to heat.

Absorbs a lot of heat from the surroundings.

The temperature of the surrounding air decreases.

Water molecules in the air condense when encountered.

When added to the dust and other solid substances in the air, they condense into small water droplets.

And then they get together, and so it gets worse"The weight of the cloud", those small water droplets and Xiaoice crystals fall under the action of gravity and then form rain. Dry ice plays a role in accelerating rainfall.

That's why it's raining.

This is because rainfall occurs when cold air currents meet moist warm air currents, causing water molecules in the air to condense.

When added to the dust and other solid substances in the air, they condense into small water droplets.

Then it comes together, and then precipitation is produced.

The principle of artificial rain on dry ice.

1. The vaporization of solid carbon dioxide in dry ice can absorb a large amount of heat and make it have the conditions for condensation.

2. There are many solid particles in dry ice, which makes it possible for water vapor to adhere.

3 As long as cumulonimbus clouds can be encountered, that is, clouds with abundant water vapor, rain can be achieved by applying dry ice shells.

The use of dry ice to volatilize into carbon dioxide gas in the clouds absorbs a large amount of heat, causing the temperature of the clouds to drop sharply. The original saturated water vapor becomes greatly oversaturated, and the supersaturated state is unstable, so that when the Xiaoice crystals increase and increase, and the air buoyancy cannot be supported, it will fall downward.

Artificial precipitation refers to the process of artificially supplementing certain necessary conditions for the formation of precipitation according to the principle of precipitation formation in nature, and promoting the rapid condensation or collision of cloud droplets and increase into raindrops and falling to the ground. The method is to choose the right time according to the physical characteristics of different clouds, and use airplanes and rockets to spread catalysts such as dry ice, silver iodide, and salt powder into the clouds.

Uses of dry ice

Dry ice has been widely used in many levels, such as cleaning equipment, refrigerating and transporting goods, fire fighting, creating clouds, artificial rainfall, etc. Carbon dioxide is not visible, in fact, it is not (carbon dioxide) smoke, it is (water) mist, carbon dioxide absorbs a lot of heat when it becomes a gas from a solid, so that the temperature of the surrounding air drops quickly, the air temperature drops, its solubility to water vapor becomes smaller, and the water vapor undergoes a liquefaction reaction, releasing heat, and it becomes a small droplet, which is fog.

This and summer popsicles emit "white mist" in the same meaning, are small water droplets, not other gaseous substances. That is, what we see is white fog and not white smoke. Dry ice is much cooler than water, so it is equivalent to heating dry ice, and dry ice absorbs heat and sublimation, so that the temperature of the water is reduced, or even frozen.

The principle of artificial rainfall by dry ice: artificial rainfall uses the physical principles of clouds and precipitation, and by spreading rainfall agent dry ice into the clouds, the cloud droplets or ice crystals increase to a certain extent, and fall to the ground to form precipitation. To put it simply, it is a method of human intervention using dry ice to condense water droplets into rain.

Dry ice is solid carbon dioxide, dry ice is highly volatile, sublimated into non-toxic, tasteless, 600-800 times larger than the solid volume of gas carbon dioxide, so dry ice can not be stored in a completely sealed volume container, such as plastic bottles, dry ice and liquid mixing is easy**.

Power Catalysis:

The latent heat released by cold cloud catalysis will change the macrodynamic process of cumulus clouds and increase precipitation. It was a development in artificial precipitation experiments in the 60s. The velocity of the updraft in cumulus clouds is mainly determined by the buoyancy caused by the temperature difference between the inside and outside of the clouds.

Within the vigorously developed Curocumulus clouds, there are a large number of supercooled water droplets.

When a large amount of ice-forming catalyst is sown in this cloud, the supercooled water droplets can freeze and release latent heat, and the water vapor also releases latent heat when it condenses on the surface of the ice particles.

It is estimated that these two latent heats are sufficient to increase the local temperature in the clouds, which will increase the buoyancy and promote the updraft velocity of some cumulus clouds, the expansion of the clouds, and the extension of their lifetimes, resulting in an increase in the total amount of water entering the clouds and an increase in precipitation.

You won't be ignorant of the principles and methods of artificial rainfall.

1.Artificial rainfall must have sufficient conditions. The generation of natural precipitation in general requires not only certain macroscopic weather conditions, but also microphysical conditions in the clouds, such as:

There should be large water droplets in warm clouds above 0; There must be ice crystals in the cold clouds below 0, without this condition, no matter how good the weather situation is, no matter how good the cloud conditions, it will not rain. However, in natural circumstances, such microphysical conditions are sometimes not available; Sometimes it is available, but it is not sufficient. The former does not produce precipitation at all; In the latter, there is very little rainfall.

At this time, if artificial ice cores are artificially sown into the clouds, the ice-water transformation process of condensation or condensation will occur in the clouds, and then with the help of the natural collision process of water droplets, rainfall can be produced or the amount of rain can be increased. The role of catalysts in clouds is, to use a less precise analogy, like salt brine tofu, which enables precipitation that would not have been produced to increase the intensity of precipitation that has already been produced.

2.The principle of industrial precipitation with dry ice:

Dry ice sublimates into gas carbon dioxide when heated, it absorbs a lot of heat from the surroundings, the temperature of the surrounding air decreases, the water molecules in the air condense when encountered, and the dust and other solid substances in the air condense into small water droplets, when the gravity of the small water droplets is greater than the buoyancy of the air on the small water droplets, the small water droplets fall, and rain is formed.

When the plane splashes dry ice into the air, it quickly vaporizes, grabs the heat in the clouds, forcing the temperature of the clouds to drop to -40 °C, and at the same time, each gram of dry ice can produce 10 billion Xiaoice crystals, and the surrounding clouds touch the Xiaoice crystals, and condense into large water droplets with it as the center, which solves the problem of long-term drought without rain.

Dry ice artificial rainfall.

Condense on it, turn into raindrops, and fall to the ground. Since the temperature of dry ice is very low, the carbon dioxide is sublimated at a low temperature.

After the gas collides with the air, the water vapor in the air can be condensed into small water droplets, so white gas appears, so dry ice is often used in stage performances to create a special effect like a cloud.

The key to artificial rainfall is the formation of condensation nuclei tolerant mode. Artificial rainfall is not sprinkled in the first can be successful, there is saturated water vapor or supersaturated water vapor in the air is a prerequisite for artificial rainfall, as long as there are enough condensation nuclei, enough raindrops can be formed. The real principle of using dry ice for artificial rainfall is to use the ultra-low temperature generated by the sublimation of dry ice to directly condense a small part of the water vapor in the air to form micro-Xiaoice crystals, and then a large amount of water vapor in the air will continue to condense into raindrops with micro-Xiaoice crystals as condensation nuclei.

Today's artificial rainfall does not use dry ice, but silver iodide.

Silver iodide particles are sprinkled directly into the air and act as condensation nuclei to cause water vapor to condense into raindrops. It does not go through the action of ultra-low temperature at all.

The principle of artificial rainfall is to choose the right time according to the physical characteristics of different cloud layers, and use airplanes, rockets, etc. to spread catalysts such as dry ice, silver iodide, and salt powder into the clouds to promote precipitation or increase precipitation in cloud formations. There are three methods of artificial rainfall: cold cloud catalysis, warm cloud catalysis and dynamic catalysis.

There are three ways of catalytic operation: one is to arrange the AGL combustion furnace on the ground as the main means; the second is ground operations based on anti-aircraft artillery and rockets; The third is aircraft catalytic operation. Commonly used catalysts are dry ice, refrigerants, and silver iodide.

Artificial rainfall can effectively carry out drought resistance in farmland or solve the problem of water use for people and livestock, as well as forest fire prevention, and it is an important scientific and technological means for meteorological departments to directly carry out drought fighting.

Notes

1.Artificial rainfall operations can only obtain the results of increasing the required amount of water under certain natural cloud conditions, and the technical conditions cannot achieve artificial rainfall.

2.The same catalytic effect on clouds under different conditions may result in both positive and negative results. Therefore, in order to obtain the effect of precipitation enhancement, it is necessary to conduct more in-depth detection studies on natural cloud conditions and precipitation processes.

3.The variability of natural precipitation is very large, and the amount of artificial precipitation is often relatively small, and it is difficult to distinguish artificial precipitation enhancement from natural rainfall in the process of precipitation. Therefore, the evaluation of the rainfall effect and its test method are still the main objectives of weather modification science.

4.Artificial precipitation has gradually changed from the initial experimental research to a test and application technology that combines strict design, a variety of detection methods, and the modernization of operation technology with communications, and has become one of the measures to fight drought and reduce disasters in China and many countries.

The above content reference: Encyclopedia - Artificial precipitation.

Quickly condenses water vapor in the air.

Principle: In the process of volatilizing dry ice into carbon dioxide gas in the clouds, it absorbs a large amount of heat, which causes more water vapor to condense on it, turn into raindrops, and fall to the ground. If the cloud base to the ground temperature is above 0, it will rain, and if the temperature is below 0, it will snow.

Artificial precipitation enhancement is divided into warm cloud precipitation enhancement and cold cloud precipitation. To cause precipitation or increase rain in clouds (clouds with a temperature higher than 0), hygroscopic particles such as salt powder and urea should be sown in the clouds in the mountains to promote the formation of large cloud droplets and lead to the formation or increase of precipitation. If cold clouds (clouds with a temperature below 0) are to be used, catalysts such as dry ice and silver iodide should be sown by airplanes, etc., to produce a large number of ice crystals, so that the density of ice crystals in the upper part of the cold cloud increases, and precipitation is promoted or increased.

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

Artificial rainfall is the use of clouds and precipitation physics to delay transportation, the use of dry ice in the cloud volatilization into carbon dioxide gas in the process of absorbing a large amount of heat, prompting more water vapor to condense on it, turn into raindrops, and fall to the ground. If the temperature from the cloud base to the ground is above 0, it will rain, and if the temperature is low, it will snow. The sedan chair is high.

Dry ice is a condensed solid state of carbon dioxide and is also useful as a refrigerant because it is useful in keeping objects frozen or cold.

Dry ice can create clouds: The temperature of dry ice is very low, which can make the water vapor in the air quickly condense into small droplets and appear white, so dry ice is often used on the stage to create a cloud effect.