What is artificial rain?

Artificial rain or “cloud seeding” is a process in which humans use technology to enhance natural precipitation conditions to produce more rain or snow from clouds.

Artificial rain involves introducing special substances into clouds so that the water droplets inside them stick together faster and harder and become heavy enough to fall to the ground.

In this method, substances such as:

Silver Iodide

Sodium Chloride (table salt)

or dry carbon dioxide (dry ice)

are usually dispersed into the clouds from an airplane or sometimes from the ground. These substances provide tiny nuclei for the formation of ice crystals. These crystals then grow, combine with the surrounding vapors, and artificial rain or snow is formed.

Objectives:

Increase rainfall in dry areas

Reduce dust and air pollution

Replenish water resources and dams

Prevent hail or weather damage (in agriculture)

Limitations and challenges:

Only effective if there are suitable clouds.

Costly and does not always give a clear result.

There are concerns about environmental effects (e.g. residual chemicals).

Examples of use:

Countries such as China, the United States, the United Arab Emirates, Iran and Australia have artificial rainmaking projects.

In Iran, these projects are sometimes carried out in the central and western regions to reduce drought, usually by the Meteorological Organization and the Ministry of Energy.

 

Types of artificial rain production methods

There are several types of artificial rain production methods (cloud seeding) and they are divided based on the type of material, the method of injection and the atmospheric conditions of the clouds. Below, I have provided a complete explanation of these methods

1. Airborne Seeding

This method is the most common type of cloud seeding.

In it, special aircraft fly at the height of the clouds and spread the seeding materials.

Method of implementation:
-The aircraft enters the cloud area.
-Through nozzles or torches, it spreads materials such as silver iodide or sodium chloride into the cloud.
-These materials cause water or ice droplets to condense and eventually precipitate.
-It is usually used in countries with strong air infrastructure (such as the United States and China).

2. Ground-Based Seeding

In this method, the target material is released from the ground, usually via smoke generators or small rockets.

How it works:

• Devices similar to smoke generators or flamethrowers release silver iodide in the form of fine particles into the air.
• Updrafts of air carry these particles into the clouds.
• This method is cheaper than the aerial method, but it is more difficult to control.

1. Dry Ice Seeding

This method uses solid carbon dioxide (dry ice).

How it works:

• Dry ice is spread into cold clouds (clouds with temperatures below zero degrees).
• By suddenly cooling the moisture in the cloud, it causes the rapid formation of ice crystals.
• These crystals grow and fall as snow or rain.
• It is effective for “cold” clouds and is usually carried out by aircraft.

1. Salt Seeding

It is specific for warm clouds (temperatures above zero degrees).

Method:

• Fine particles of sodium chloride (salt) are sprayed into the clouds.
• Small droplets of water vapor stick to them and grow to rain.
  It is used in coastal or humid areas (such as the Emirates and Thailand).

1. Electric or plasma method (newer)

In this method, which is still being tested, laser beams or electric fields are used to excite air particles and condense water vapor.

• Its advantage: no chemicals

Challenges: High cost and the need for specialized equipment

 

Advantages and Disadvantages of Artificial Rain Production

Artificial rain (cloud seeding) can be a great help in water resource management, but it also has its disadvantages and challenges.

Below, I have listed its advantages and disadvantages in a comprehensive and systematic manner
Advantages of Artificial Rain Production

1. Increasing water resources

• Its most important benefit is “increasing rainfall” in arid and semi-arid regions.
• It can help fill dams, groundwater tables and river water.

1. Helping agriculture

• It improves the natural irrigation of fields and prevents crops from being destroyed during drought periods.
• In some countries, the timing of artificial rain is precisely adjusted to the water needs of plants.

1. Reducing pollution and dust

• Rain can wash suspended particles, soot and pollution from the air.
• It is useful for cities with polluted air (such as Tehran or Delhi).

1. Helping to control forest fires

-Sometimes used in forest areas to humidify the air and ground as an auxiliary method for controlling fires.

5. Using advanced technologies

-It leads to the development of meteorological knowledge and new technologies such as special aircraft, drones and cloud data analysis.

Disadvantages of artificial rain production

1. High cost

• Flight operations, chemicals (such as silver iodide) and continuous monitoring are very expensive.
• Usually only countries with large budgets can operate continuously.

1. Dependence on cloud conditions

• Artificial rain is only effective when there is suitable cloud cover.
• In clear or dry weather, it does not produce any results.

1. Potential environmental impacts

• There are concerns about the accumulation of chemicals in soil, plants and water sources.
• Although the amounts used are usually small, the long-term effects have not yet been fully established.

1. Uncertain results

• Cloud behavior is difficult to predict, so artificial rain does not always give the desired result.
• Sometimes the amount of precipitation is less or more than predicted.

1. Political and legal aspects

• It may cause tension on the border between countries, as it is not clear which country “owns” the clouds.
  -Some countries believe that cloud seeding in the neighborhood may empty their own clouds.