Rain can be annoying. We wet, it makes us sad and can ruin certain days. In fact it is no coincidence that there are companies that charge by making sure no rain on your wedding day. But if there is something worse than the rain is the lack of it, which is why more and more countries investing money in cloud seeding.
Although it may seem like something out of a science fiction book, the truth is that we seeding clouds over fifty years and making it rain or snow in some places artificially. There are many companies and governments investing money to develop different techniques to achieve this, but they all have a common origin.
Who would want it to rain?
But why make it rain? The reasons are as varied, from politicians who want to look like they are helping more farmers to firefighters or the obvious needs of those areas of the world suffering from recurrent droughts that are leaving in misery to thousands of people.
In July 1946, American chemist and meteorologist Vincent Schaefer was the first to produce artificial snow. CO2 in solid phase in a refrigerator to cause a drop in temperature, but realized that the water cooled in the air was forming clouds of ice crystals. Shortly afterwards he developed his technique and was also able to do it rain outdoors.
There are up to 34 companies dedicated to plant rain
Since then they have created a total of 34 private companies around the world who live on weather modification. They are also using these techniques as the Chinese government, which clouds harvest in 22 of its 23 provinces both to combat pollution in large cities and to improve rainfall for agriculture.
Years ago there were several debates on whether to make it rain in a city was like stealing the rain to another city that the cloud was heading, but today meteorologists like the American Dave Reynolds are clear: “The clouds are continuously regenerated, and They are arising from only a portion of its moisture when it rains. ” Translated into plain language, that means that cause rainfall does not rain less elsewhere, but more rain in several places.
How can you make it rain?
Depending on the weather and the place there are several different ways to conduct cloud seeding. The most common are where substances such as silver iodide are used, or where dry ice or frozen carbon dioxide is used. To be effective it is necessary that the cloud containing water supercooled liquid or below zero degrees.
The substance as silver iodide has a shaped structure similar to the ice crystal, and acts causing one nucleation of ice crystals from these water droplets. Using dry ice do not need water to exist as a material that expands, cools the air to create ice from the vapor. Still, if it needs to be if we want these ice crystals grow enough to create precipitation.
These techniques concern to some people because silver iodide in high concentrations can be harmful to health. But studies in the United States has determined that the amount of this compound in snowflakes artificially created is so small that it is virtually undetectable. In fact greater amounts were detected in places where not even harvesting techniques have been used cloud.
You can seed clouds using salt
In some other warmer areas as India it is gaining in popularity performing cloud seeding using hygroscopic materials such as salt. Water molecules are attracted to the salt, which serves to attract them, join them and make them raindrops.
Employers who engage in such activities warn that its techniques are not a Holy Grail that can cause rain of nowhere, insisting that “it is so difficult to know if you can cause it to rain like predicting the weather” since no two equal clouds . There is also the problem that there needs to be clouds, but we are already working on systems capable of creating rain clouds with lasers.