Imagine you can control the weather at will. Especially in drought or water-scarce areas, it can produce rainfall as needed. If you think about it, it would seem that such a thing is not possible without science fiction.
But artificial rain, also known as ‘cloud seeding’, is actually possible. In fact, this technology has been used in various countries for many years to increase rainfall.
Cloud seeding has been applied to modify cloud structure since the 1940s. In this technology certain substances are dispersed in the air. It increases the chance of rain in that area or changes the amount of rainfall.
However, experiments with cloud seeding began about 1 century ago. Experiments with this method first began at least as early as the 20th century. Even after all these years, the effectiveness of cloud seeding is still debated. Experts are skeptical about how much precipitation actually increases due to cloud seeding.
One of the reasons for such skepticism about cloud seeding is the lack of comparability. As much as cloud seeding is done in the clouds, it rains. However, it is difficult to find out by comparison how much rain would have occurred if this method had not been applied to that cloud, or whether it would have occurred at all.
During the ‘Vietnam War’ the US Army conducted an operation to increase rainfall over the country. The purpose of the operation, called ‘Operation Popeye’, was to slow down the movement of trucks or vehicles of the Vietnamese military by making it rain.
However, the first allegations of this covert operation by the US military were made 60 years after the end of the war. For that reason, there are doubts about how successful this operation was actually conducted.
Attempts to artificially increase rainfall are not ‘climate engineering’. ‘Climate engineering’ is a technology that attempts to artificially change the climate.
Climate engineering is mainly used to prevent global warming or environmental disaster. It differs from cloud seeding or artificial rain.
Cloud seeding is a method of temporarily changing the weather in certain regions.
What Is Cloud Seeding?
One method of changing the weather in a particular region is called cloud seeding. Through this, an attempt is made to increase or decrease the amount of rain or snow falling at a place. Scientists from different parts of the world have been experimenting with this technology since the 1940s.
Cloud seeding is done in different techniques or processes. A common technique is to apply various chemical salts inside the cloud. In this process, artificial rainfall is caused by sending drones in the sky or with the help of devices on the ground.
Silver iodide or potassium chloride to table salt sodium chloride are also used for cloud seeding.
Salt acts as an agent to retain moisture in clouds. This accumulated moisture later turns into ice crystals. When these crystals fall from the clouds to the ground, they melt and cause precipitation.
Another technique for cloud seeding is to use electrical charges from drones flying at low altitudes. There is an intriguing scientific theory behind it. The greater the charge difference between water droplets in a cloud, the stronger their attraction to each other.
When an electrical charge is applied to the cloud, the water droplets within it are stimulated to coalesce. As a result, the chance of rain from those clouds increases.
However, cloud seeding technology does not miraculously produce rain in a cloudless sky. A lot of initiative, enthusiasm and hard work is needed for this work. Salt particles can only be applied to clouds that already contain moisture to cause precipitation.
For example, during the dry season, the UAE Meteorological Department monitors the sky to find these exact clouds. When such clouds are found, aircraft pilots are instructed to start cloud seeding.
A typical cloud seeding operation can last about 4 hours. 5 to 6 of these clouds are made for rain. It costs about 3 thousand US dollars to do this once.
There is also much debate about cloud seeding. For example, when such substances are sprayed into clouds, the amount of polluting particles or ‘micro-pollutants’ in the atmosphere increases. This can lead to respiratory diseases in the public.
Like many other countries, the United Arab Emirates is also experimenting with this technology. But the infrastructure of different cities of the country is not suitable for heavy rains.
Artificial Rainfall Is Necessary
Most of us know how it rains. It starts with the evaporation of water. Water first turns into steam from the ocean or any other body of water.
This vapor then rises to the top of the atmosphere. Along with the air, these vapors reach the troposphere at some point. The troposphere is the lowest layer of the atmosphere. From this layer the water droplets in the vapor slowly coalesce. In this way the water droplets continue to coalesce until the droplet thickness approaches 0.1 millimeter.
When the water droplets become so thick they can no longer float in the clouds and fall to the ground as raindrops.
So what is the cause of drought or lack of rain?
Many times it is seen that there are clouds in the sky but it is not raining. This happens when the temperature of a cloud is close to 0 degrees. Such clouds may contain ice crystals, which cannot melt and fall as raindrops. Also, the water vapor in the clouds is often not condensed into liquid form.
If this is the case, artificial rainfall is tried. And for this, cloud seeding technology is used.
How Artificial Precipitation Is Produced
First, the atmosphere of a certain region is changed with the help of chemicals. This creates clouds in that region. The chemicals used for this, absorb the water vapor and help the condensation process.
Materials like calcium oxide or calcium carbonate are quite popular among the common chemicals used in this work. Besides, urea and ammonium nitrate or chloride compounds are used.
In the second stage the mass or density of the cloud is increased. And to do that, substances like urea, dry ice (carbon dioxide stored in solid form) or table salt are used.
Finally, pressurized canisters spray dry ice or cooling chemicals such as iodide into the cloud. This creates water droplets in the cloud, which then fall as rain.
Procedures
Cloud seeding is done by several methods such as salt, electric charge and infrared laser pulses.
- Chemical salt based method Chemicals used for cloud seeding include silver iodide, potassium iodide and dry ice or solid carbon dioxide. Beyond that is the use of liquid propane, which turns into a gas when released into the atmosphere. The substance can form ice crystals at higher temperatures than silver iodide. After several studies, the use of table salt has also become possible. Basically, the main function of these substances is to attract and hold water molecules. During cloud seeding, snow can occur if the cloud temperature is between −20 and −7 °C. This happens when substances like silver iodide are used. Because its structure is crystalline like ice.
Cloud seeding in mid-altitude clouds is based on a special principle of matter. The principle is that ice has a lower vapor pressure than water. As a result, small droplets of water accumulated in frozen clouds coalesce to form ice particles.
Thus, when enough ice particles accumulate in a cloud, it becomes heavy and falls to the ground as rain. Without cloud seeding, there would be no chance of rain from those clouds. This process of artificial precipitation is known as “static seeding”.
On the other hand, cloud seeding in visible cumulus clouds in warm-season or tropical regions is called “dynamic seeding”. Cumulonimbus clouds are called cumulonimbus clouds.
“Dynamic seeding” basically tries to exploit the latent heat released during the formation of ice particles. This excess latent heat is thought to lighten the clouds and increase the speed of the upward wind. This creates more clouds below. Overall, the size and volume of clouds specific to cloud seeding continues to increase rapidly.
Chemicals used for cloud seeding can be spread directly from aircraft or by ground-based equipment. This work is done with the help of a special type of dispersion device from the ground. Or generators or canisters are fired at specific clouds with anti-aircraft guns or rockets.
During cloud seeding from the ground, fine particles of chemicals first descend towards the ground via air currents. It then moves towards the clouds with the help of upward winds.
On the other hand, silver iodide flame is ignited to release these chemicals from the aircraft. Then, as the plane flies through the clouds, the chemicals it carries are released into the atmosphere.
- Electric charge dependent method Since 2021, the UAE has been doing cloud seeding with electric charge emitters. The country’s government is artificially causing rain by using drones equipped with such devices and special sensors. These drones fly at low altitudes and deliver electrical charges to air molecules. In this manner, a significant amount of rain fell in the country in the month of July 2021. In particular, rainfall of up to 6.9 mm was recorded in Al-Ain city on July 20 and 21 of that year. .
- Infrared laser pulse based method In 2010, another new type of cloud seeding method was experimentally used in the skies over Berlin. Researchers at the University of Geneva tried to induce precipitation using infrared laser pulses. The researchers claimed that with the help of the thrown laser, sulfur dioxide and nitrogen dioxide particles will be created in the atmosphere. In the presence of these particles in the cloud, rain can be successfully produced. However, no successful application of this method was seen after that study.
Is Cloud Seeding Effective?
How effective the method of artificial precipitation through cloud seeding will be depends on various factors. Its effectiveness depends on atmospheric conditions, the location of the target cloud, and the method of cloud seeding.
However, although cloud seeding has had positive results in some cases, it is not a sure-fire solution. So far, cloud seeding is considered as a complementary method rather than a substitute for natural precipitation.
How Artificial Rain Can Improve Air Quality
Cloud seeding can improve air quality in several ways. Some of these are:
- Reduces Air Pollutants: Pollutants like particulate matter (PM), nitrogen oxides and sulfur dioxide are present in the air around us. These pollutants can cause a variety of health problems, including lung disease, heart disease and cancer. Artificial rain reduces the amount of these substances in the air.
- Increases humidity: Artificial rain can increase the humidity level in the air. Air pollutants cannot disperse easily when humidity is high. In this way the total air pollution level in a region can be reduced.
- Reduces the amount of dust and other particles in the air: Artificial rain can help reduce the amount of dust and other particles in the air. These tiny particles, including dust, can irritate the eyes, nose and throat if they are in the air. Complications like asthma and shortness of breath may also develop. Apart from such direct effects, artificial rain can also indirectly affect air quality. For example, artificial rain can help improve water quality in reservoirs or water bodies. This can reduce air pollution levels from sources such as wastewater treatment plants or industrial plants. Artificial rain also helps plants grow. These plants contribute in absorbing pollutants from the air.
Is cloud seeding safe for the environment?
Although cloud seeding increases the chance of precipitation, the technology also poses some risks to the environment. Researchers have expressed concern about long-term effects such as the removal of rainwater from the area, the possibility of flooding, or the long-term presence of chemicals in nature.
Beyond that, some advocate caution against disrupting the natural cycle or flow of weather. They see various natural disasters occurring in recent times as a response to interference with the laws of nature.
Artificial precipitation through cloud seeding in one area can affect other areas. In particular, unexpected rainfall in one region can create drought-like conditions in other regions.
Also in areas where cloud seeding technology is used, flooding is often seen due to excess rainfall. Because there is no infrastructure to handle excess water flow. This can lead to major natural disasters like floods.
In addition to such immediate effects, scientists are warning about the long-term effects of cloud seeding. Especially if substances like silver iodide are used for this work, it has a bad effect on the environment.
These chemicals contribute to ocean acidification, ozone layer depletion, and increased atmospheric carbon dioxide levels. Being toxic, silver iodide poses a risk to plant, animal and human health besides adversely affecting ecosystems.
Besides, research on nanomaterials for cloud seeding is ongoing. New types of these materials are being experimented with to reduce the negative impact of this technology on the environment and at the same time effectively increase rainfall.
Artificial Rainfall In China
One of the most famous examples of artificial rain is during the 2008 Olympics in China. That year, the country’s “National Meteorological Change Office” took measures to prevent rain over the 91,000-seat stadium in Beijing, known as the “Bird’s Nest”. The office operates under the China Meteorological Administration.
The country’s authorities monitor Beijing’s weather using satellites, aircraft, radar and the IBM P575 supercomputer. This supercomputer is capable of 9.8 trillion calculations per second.
With the help of the supercomputer, an area of 44 thousand square kilometers or 17 thousand square miles is accurately modeled. It provides hourly weather forecast for every kilometer area.
Then the process of cloud seeding begins. 2 aircraft and a network of 20 artillery and rocket-launch sites were deployed around Beijing. These used silver iodide and dry ice to remove rain from clouds that were drifting towards the stadium even though they were some distance away.
In other words, the government officials of the country have already poured rain from the clouds that would have rained over the stadium.
However, arrangements were made in case any rain clouds loomed over the stadium. As part of this system, chemicals were created that could be dispersed into clouds to reduce the size of water droplets. In this way, they had a plan to hold off the rain until the clouds cleared from the stadium.
Earlier in 1958, the Chinese government began experimenting with weather control to combat the arid conditions in the country’s northern regions. The region was repeatedly threatened by drought and famine due to sudden storms from the Gobi desert.
However, the country’s government currently allocates tens of millions of dollars each year to their ‘National Climate Change Office’. Between 1999 and 2007, the office protected an area of 470,000 square kilometers from hail, according to data from China’s state news agency Xinhua. They also produced more than 250 billion tons of rain. With this amount of water, it is possible to fill China’s second largest river ‘Yellow River’ 4 times.
Apart from the 2008 Olympics, cloud seeding has also been used to influence weather conditions during many national events and programs held in the country. Some of the notable events where artificial rainfall technology has been used are the World Expo in Yunnan, the Asian Games in Shanghai and the Giant Panda Festival in Sichuan.
Cloud Seeding In Russia
The Russian administration once spent more than a million dollars to prevent rain on the country’s public holidays. The government will allocate about 86 million rubles, or $1.3 million, to ensure dry weather during May Day or May Day celebrations, the country’s state news agency reported.
But what was the result of their efforts? According to some news reports, it rained lightly that day.
So did cloud seeding successfully reduce the impact of rain that day? Or did this attempt fail due to rain? Did cloud seeding have any noticeable effect on the rain that day?
It is almost impossible to answer any of these questions with certainty.
Artificial Rain In UAE
The UAE government is using cloud seeding technology to address water scarcity challenges within their country. The country is pioneering the use of cloud seeding technology in the Persian Gulf region.
Citizens of this country suffer from water insecurity due to extreme hot weather. Researchers are trying artificial rainfall to solve this problem. Researchers continuously monitor the country’s atmosphere using special radars to monitor the weather.
Experts and scientists have calculated that cloud seeding technology can increase rainfall by 30-35% in dry atmosphere and 10-15% in humid environment.
The UAE’s cloud seeding program began in 1982. The aim of this project was to produce precipitation by condensation of water in clouds. Natural salts are used for cloud seeding under this program to avoid harmful effects on the environment.
Atmospheric conditions and pollutants are measured and analyzed prior to artificial precipitation. According to the country’s government, this initiative can be a sustainable solution to the climate challenge.
But, even though it has been implemented in many countries, some questions remain about the environmental risks and effectiveness of cloud seeding.
