UK University of Reading helps UAE to test cloud-busting drones to boost rainfall

    01 Jun 2021

    Drones that fly into clouds, giving them an electric shock to “cajole them” into producing rain, were tested in the United Arab Emirates, Bath reports.

    A new method to trigger rain in places where water is scarce is being tested in the United Arab Emirates using unmanned drones that were designed and manufactured at the University of Bath. The drones carry an electric charge that is released into a cloud, giving cloud droplets the jolt they need to clump together and fall as rain.

    This is one of the first times scientists have used drones in an attempt to stimulate rainfall from clouds. Established techniques for encouraging rainfall in dry countries involve low-flying aircraft or rockets dropping or firing solid particles (such as salt or silver iodide) into clouds. This is known as cloud seeding.

    The country already uses cloud-seeding technology, dropping salt to encourage precipitation.

    But with average rainfall in the UAE at just 100mm per year, the country wants to generate more.

    In 2017, the government provided $15m (£10.8m) for nine different rain-enhancement projects. Scientists at the University of Reading (UK) are heading one of them, Arab News reports.

    The project aims to change the balance of electrical charge on cloud droplets, explained Prof Maarten Ambaum, who worked on the project.

    “The water table is sinking drastically in [the] UAE and the purpose of this is to try to help with rainfall,” he told the BBC.

    The country does, though, “have plenty of clouds”, so the plan is to persuade the water droplets in them to merge and stick together, “like dry hair to a comb” when it meets static electricity, he said.

    “When the drops merge and are big enough, they will fall as rain.”

    Alya Al-Mazroui, director of the UAE’s rain-enhancement science-research program, told Arab News: “Equipped with a payload of electric-charge emission instruments and customised sensors, these drones will fly at low altitudes and deliver an electric charge to air molecules, which should encourage precipitation.”

    The study will then be evaluated, with the hope of more funding for a larger aircraft to deliver the payload in future.

    Al-Mazroui says it’s too early to predict the effectiveness of the study. It’s one of nine “rain enhancement” projects given $15 million from the UAE’s Ministry of Presidential Affairs.

    The drones, which are being tested as part of the UAE’s rain-enhancement science-research program, are equipped with a payload of electric-charge emission instruments and sensors. Human operators on the ground will direct them towards low-hanging clouds, where they will release their charge. Clouds naturally carry positive and negative charges. By altering the balance of these charges, it is hoped that cloud droplets can be persuaded to grow and merge, eventually producing rain.

    The research, which is published in the Journal of Atmospheric and Oceanic Technology, is being led by the University of Reading, however both the drones and some of the equipment they carry were developed by researchers from the Department of Electronic and Electrical Engineering at Bath. The first drone flights in the Emirates are expected to take place in the next few months.

    Dr Keri Nicoll, who coordinated the research at the University of Bath and is now a visiting scientist at Bath, based at the University of Reading, said: “We’ve done tests in the UK and demonstrated that we can release charge from the aircraft and detect it on the ground. The next step is to repeat these tests in the UAE, where the ambient electrical environment is very different to the UK, due to high levels of dust and aerosol particles.”

    Water stress is a major problem in much of the Arab world, including the UAE. The average rainfall in the Emirates is 100mm per year (compared to 885mm in the UK) and the country is expected to get drier and more arid as temperatures rise due to global warming.

    “Water scarcity is one of the biggest problems facing humanity, and climate change is providing more uncertainty around rainfall,” said Dr Nicoll, adding: “In those parts of the world that are really struggling for water, projects to improve rainfall are really important, and there are 50 nations that have established rainfall enhancement programs. They already do cloud-seeding in the United Arab Emirates (using salt particles, released from manned aircraft) but they are eager to come up with other ways to get water to the population.”

    Dr Nicoll is hopeful that the technology produced for the project could be used to stimulate clouds to produce rain in the years to come. “It is likely that charging cloud droplets on its own won’t replace established cloud-seeding techniques, but it could work alongside existing techniques to maximise the efficiency of cloud seeding,” she said.

    His Excellency Dr Abdulla Al Mandous, Director of the National Center of Meteorology (NCM) funding for the country’s rain-enhancement program “are crucial in driving and encouraging innovation in applied scientific research to advance global rain enhancement capacity.”

    He added that NCM “is committed to mitigating the risk of water stress on arid and semi-arid regions around the world, while enhancing the country’s status as global hub for rain enhancement research.”

    Can drones make it rain?

    There are drones that capture weather data, but actually making weather seems new. Can this really work?

    Wired reports the UAE experimented with more than 185 different cloud seeding projects in 2019. And one October torrent actually caused floods in Dubai. It’s hard to know if there is a direct correlation. Everyone can see the weather is becoming less predictable. Still, electrical arcs sound more environmentally friendly than seeding clouds with chemicals like silver iodide and titanium dioxide

    There are similar initiatives around the globe. E.g., Indonesian authorities are turning to the technique of cloud seeding to try to stop more rain falling in the flood-hit capital Jakarta. In January, 2020, planes have been sent to inject chemicals into clouds in an effort to alter precipitation.

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