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  • What's that in the sky?

  • Is that a bird?

  • Superman?

  • Chemtrails?

  • Cloud seeding?

  • What the hell is cloud seeding?

  • Hey guys, Julia here for DNews

  • Humans like to make it rain.

  • From rain dances to Storm in X-men we've always dreamed of controlling the weather.

  • Apart from rituals and science fiction, science might have found a way.

  • Clouds are made of millions of tiny water droplets.

  • But these droplets hang out in the air unless they stick to tiny particles.

  • Then they become heavy enough to fall.

  • Normally these particles are things like dust.

  • A study published in the journal Geophysical Research Letters found that pollen might help

  • form clouds too.

  • Previously scientists thought that pollen grains were too large to have any effect on

  • weather.

  • Yet this new research suggests that when pollen gets wet it breaks apart into smaller pieces.

  • And these smaller pieces could make the building blocks of clouds.

  • So it seems like a small leap of logic to find a way we could help the process along.

  • Maybe we could make clouds out of thin air.

  • Sound like science fiction?

  • Well it's already a thing.

  • It's been a thing in the American west for decades already.

  • In California, water agencies and utilities dish out $3-to-5 million bucks a year on it.

  • Cloud seeding produces nucleation, when water particles attach to other small particles

  • and condenses.

  • Basically it makes water vapor form clump into a cloud.

  • If it gets heavy enough, it falls to the ground as rain.

  • One study published in the Journal of Applied Meteorology and Climatology found that this

  • process can improve rainfall by up to 15%.

  • While that doesn't seem like a lot, this technique proved effective in a desert in

  • 2010.

  • An 11 million dollar project produced 52 rain storms in the Abu Dhabi desert.

  • In this case, scientists working for the United Arab government designed ionizers, which produced

  • charged particles.

  • As they rose into the atmosphere, these particles collected dust.

  • When water particles condensed around the dust, it formed cloudswhich turned into

  • rain.

  • Worried your wedding day might be a little wet?

  • Well, London based luxury travel company, Oliver's Travels can help.

  • they'll have a pilot fly near your event location and sprinkle a few silver iodide

  • particles into the air a few days before the shindig.

  • These particles, look very close to ice on a molecular level.

  • So they make water condense and well you get the idea.

  • Rain happens.

  • This clears the air, so clouds won't build up on your big day.

  • Although prepare to cough up a pretty penny.

  • The service can run $150,000.

  • I know what you're thinking - can we just make a bunch of rainclouds and end the drought?

  • Well there are some skeptics, one study published in the journal Atmospheric Research found

  • some cloud seeding attempts aren't all that successful.

  • Looking over a 50 year period, the researchers conclude that an increase in rainfall was

  • the result of chance, not cloud seeding.

  • But other scientists think it could tame hurricanes.

  • In a study published in the journal Atmospheric Science Letters researchers create climate

  • models to understand how creating clouds could cool down the oceans.

  • Hurricanes get whipped by warm waters in the ocean.

  • As sea surface temperatures heat up, hurricanes get more energy.

  • By creating clouds above ocean hot spots, the clouds could act like reflectors, bouncing

  • the sun's energy back into space.

  • But on the other hand, such clouds might reduce rainfall in the Amazon or cause other unintended

  • consequences.

  • Which is the main problem with the whole cloud seeding thing.

  • You can't predict the weather, even if you make it.

  • So more research is needed.

  • So it might not save us from a drought, but could the ocean save us?

  • Julian finds out in this episode here

What's that in the sky?

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B1 中級 美國腔

人造云能否将我们从干旱中拯救出来?(Can Man-Made Clouds Save Us From The Drought?)

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    joey joey 發佈於 2021 年 04 月 17 日
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