Cloud-zapping drones: yeah; why not?

Up until around the year 2015, the first question you got when you mentioned the word drone was probably, what does a drone do?

Fast forward six years later, and the question has turned on its head – what can a drone not do? Because apparently, there is nothing an unmanned aerial vehicle cannot do for humans now – well, except maybe grant inherent human qualities like good judgement and kindness and compassion and free will. They may fix our wars and our walls and our other industrial conundrums that have to do with productivity; but for the qualities that makes us human?

That could be too far a step, even for a drone.

So we have restricted drone technology to merely taking care of a few industrial and recreational operations like agriculture, mining, delivery, survey and mapping, construction, GIS, inspections, search and rescue, policing, security, media production, aerial photogrammetry, environmental and wildlife conservation…

You know, every industrial application you can think of; and apparently – according to this report from CNN – cloud zapping.

And we are back to 2015 again; what on earth is cloud zapping?

Scientists at University of Reading in the UK, who are looking for a long term answer to drought in the world, describe cloud zapping as a process of charging water droplets in clouds with electricity in the hope that they will grow and start falling as rain.

And the idea, which is now being supported financially by the United Arab Emirates, is to fly drones into the clouds which will zap them into rainfall.

With a harsh, desert climate and an average rainfall of just 10 cm a year, the UAE finds itself in need of more freshwater. In search of a solution, it has been funding science projects from around the world to try to make it rain.

One of these projects involves using catapults to launch small unmanned aircraft which zap clouds with an electric charge.

The team of scientists from the University of Reading initially proposed the idea in 2017.

Now, the custom-built drones will soon begin tests near Dubai.

Let’s go make it rain…

The idea is that charging droplets in clouds will make them more likely to fall as rain.

“There’s been a lot of speculation about what charge might do to cloud droplets, but there’s been very little practical and detailed investigation,” says Keri Nicoll, one of the core investigators on the project. “The aim is to determine if the technology can increase rainfall rates in water-stressed regions.”

Nicoll’s team started out by modelling the behaviour of clouds, where they discovered that when cloud droplets have a positive or negative electrical charge, the smaller droplets are more likely to merge and grow to become big raindrops.

The size of the raindrops is important, says Nicoll, because in places like the UAE which has high clouds and high temperatures, droplets often evaporate as they fall.

“What we are trying to do is to make the droplets inside the clouds big enough so that when they fall out of the cloud, they survive down to the surface,” says Nicoll.

The proposal was chosen to receive a $1.5 million grant distributed over three years by the UAE Research Program for Rain Enhancement Science, an initiative run by the National Centre of Meteorology.

To test out the model, Nicoll and her team built four aircraft with a wingspan of two meters. These are launched from a catapult, have a full autopilot system, and can fly for around 40 minutes.

Each aircraft has sensors for measuring temperature, charge, and humidity, as well as charge emitters — the part that does the zapping — that were developed with the University of Bath in the UK.

So far, testing has been conducted in the UK and Finland, and ground-based measurements of cloud properties taken in the UAE. The research has been published in the Journal of Atmospheric and Oceanic Technology.

Because the pandemic meant Nicoll’s team couldn’t travel to the UAE, they have trained operators from a flight school in Dubai to use their aircraft.

They’re now waiting for the right weather conditions to complete the tests.

As climate change alters weather patterns, causing severe droughts in some places and floods in others, there is a growing interest among governments and meteorologists in how to control the weather. According to the World Wildlife Fund, two thirds of the world’s population may face water shortages by 2025.

While the University of Reading project is coming to an end this year, Nicoll wants future projects to combine charging clouds with cloud seeding — an existing weather modification technique where drones inject particles of silver iodide or salt into clouds to encourage them to rain or snow.

Nicoll says using charged salt particles could make cloud seeding more efficient.

“There’s still a long way to go to definitively see how effective cloud seeding weather modification is at enhancing rainfall,” says Nicoll.

But the world may soon be one step closer to finding out how effective cloud zapping can be.


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