Forgot your password?
typodupeerror
Earth Transportation News Science

Airplanes Cause Accidental Cloud Seeding 151

Posted by timothy
from the you-think-boeing-and-seattle-is-a-coincidence? dept.
An anonymous reader writes "A new study by a team of U.S. researchers found that commercial and private jetliners may be contributing to a form of accidental cloud seeding. When an airplane flies through a cloud, its propellers cause the expansion and cooling of the air behind them which can cause water droplets to spontaneously cool and crystals to form. The aircraft sets off a chain reaction in the cloud that can continue on for hours after the plane has passed by. The researchers also discovered that this phenomenon is more common near the poles, where many of Earth's weather monitoring systems are, and it could be skewing data that research teams are gathering in those areas."
This discussion has been archived. No new comments can be posted.

Airplanes Cause Accidental Cloud Seeding

Comments Filter:
  • Not new news (Score:5, Informative)

    by Afforess (1310263) <afforess@gmail.com> on Friday July 01, 2011 @07:54PM (#36638644) Journal
    Meteorologists have known about this for some time. They tend to form what is known as "Hole Punch" clouds.

    Examples: http://bit.ly/lAxNQO [bit.ly]
    • Meteorologists have known about this for some time.

      The common term for it is "contrails."

      Yes, it's well known that contrails sometimes to grow into cloud cover. (High altitude thin clouds, not puffy cumulus ones). This is not news.

      • by sjwt (161428)

        I do believe you did not look at the photos, so from another website, here is some text for you to read.

        As a note, because of what ever technical reason stooped you looking a the lint, these clouds can and do look at times look like massive eyes or holes in the clouds, nothing at all like contrails, and in some cases can look like a massive gouge taken out of the clouds, kinda like a revers contrail.

        http://www.weatherthings.com/HolePunch.html [weatherthings.com]

        "A “Hole Punch” cloud is a non-technical name given t

      • This is actually not about contrails, but quite the opposite. A contrail is a cloud created by the passage of an airplane (due to the vapor from the engine or simply the dynamic effect of stirring up oversaturated air). This study is about airplanes flying through clouds and causing those clouds to start raining. In a way, they are erasing clouds ("punching holes" in them)
    • I can't believe I actually fell for clicking on this... ... good thing it's legit.

  • How is this news (Score:5, Informative)

    by Anonymous Coward on Friday July 01, 2011 @07:55PM (#36638646)

    I mean seriously, this has been known for decades. There was even a study that looked at the 9-11 shutdown of air-traffic affected climate [cnn.com].

    This has been known for a long time.

    • Precisely. Someone mod parent up please.
      • I have only flown across the US once (I am an Australian) but I was surprised to see how many contrails we crossed going from New York to Los Angeles. It may be the distributed nature of the US population. Aircraft go all over the place and cross each others paths with surprising frequency.

    • I agree with what you said, I just want to do some CNN-bashing:
      Those damn journalists were trying to be sensational again by saying that the air traffic affects the *climate* while it is obvious that it just affects the *weather*. If the air traffic disappears the *weather* will just roll back to its usual behavior that is dictated by the *climate*. Of course, I am only taking about the condensation wisps that are referred to in the article, not the aircraft emissions, that do have an effect on the *climate

      • by isorox (205688)

        I agree with what you said, I just want to do some CNN-bashing:
        Those damn journalists were trying to be sensational again by saying that the air traffic affects the *climate* while it is obvious that it just affects the *weather*. If the air traffic disappears the *weather* will just roll back to its usual behavior that is dictated by the *climate*. Of course, I am only taking about the condensation wisps that are referred to in the article, not the aircraft emissions, that do have an effect on the *climate*.

        But I guess the word weather is out of fashion, and climate sounds so much better... Damned journalists, I hate you guys...

        It's a problem with journalists. "Climate" sounds sexier than "Weather" just like "Deficit" is sexier than "Debt". These terms start off being correctly used, but soon fall away and reports gets "sexed up"

      • by Misagon (1135)

        If planes do this all the time, 24/7, 7 days a week, all year around, then what is the difference? It is precisely as if planes changed the climate.

        There is a theory that seeding from airplanes was the main cause of the drought in Etiopia back in the 1980s.
        I'm not a tin-foil-hat guy, but sometimes weird theories are proven right.

        • You have a point, but the difference is the time scale for recovery. As reported in the CNN article, 3 days of grounding were enough to notice a difference. If something changes in the climate it will take much longer than 3 days for things to roll back to their previous state (if ever).

      • We've had airplanes buzzing through the skies for a century. Over all, they could be a climate altering force.
    • by Lost Race (681080)
      See also NOVA: Dimming the Sun [pbs.org], which discusses, among other things, the effect of the September 2001 air traffic shutdown on weather (not climate).
  • Next week when we come by for Slash Dot Mystery Time, can we talk about how steam valves and clock gears work?

    That would also be a slide in the ice-house.

  • by Osgeld (1900440)

    Please quit wasting our tax money, seriously the people who did this study should have their funding removed as all they have done is have a "no shit mr 1934" moment over technology that is darn near extinct

    • Don't jet engines have a propeller-like thing called a turbine? Wouldn't they have a similar effect?
      • by Osgeld (1900440)

        Similar as in they are objects that spin, but otherwise no, not really

        hell do us a favour and go stand behind a jet engine and let us know how cool the air feels to you

      • Re:arg (Score:5, Informative)

        by mcgrew (92797) * on Friday July 01, 2011 @09:59PM (#36639224) Homepage Journal

        Oh, ferkrissakes, I came here to use up my last two mod points and almost every comment is ignorant, so I'm going to just make one comment and watch a movie and use those two points in the morning.

        I know it's not usual for anybody to RTFA and instead just jump to conclusions thinking you know everything without having a clue, so I'm going to clue a few of you guys. This is not about contrails. Of course contrails have been known about forever. I didn't read this particular FA but I saw another FA about this earlier today, and it was damned interesting.

        If it was about contrails, most of you guys would still be wrong. Contrails aren't caused by the turbines, they're caused by the air passing the wingtips of the aircraft. If you want to learn more, there's wikipedia for that.

        This is about circular holes in clouds, It's about the exact OPPOSITE if contrails. The cause of contrails is well known, the cause of this particular phenomena isn't known. I find it hilarious that you guys think you know more about physics than folks who've been studying physics all their lives.

        I'm not a physicist or meteorologist, but at least I know enough to know the limits of my own ignorance, so I READ. Voraciously. The more I read the more I learn, the more I learn the more I understand how ignorant I am. You guys might try reading once in a while. You're ignorant -- we're all ignorant. A physicist doesn't know shit about cosmology, and a cosmologist doesn't know shit about paleontology.

        The man who thinks he knows everything cannot learn. Thus endeth the lesson, grasshopper.

        • Re:arg (Score:5, Informative)

          by AnObfuscator (812343) <onering@phys. u f l .edu> on Friday July 01, 2011 @10:49PM (#36639382) Homepage

          If it was about contrails, most of you guys would still be wrong. Contrails aren't caused by the turbines, they're caused by the air passing the wingtips of the aircraft. If you want to learn more, there's wikipedia for that.

          Ironic, considering the tone of your post, but I actually *did* look up (and read) the contrails article on Wikipedia, and you are in fact very wrong. http://en.wikipedia.org/w/index.php?title=Contrail&oldid=436631379 [wikipedia.org]

          Contrails (play /kntrelz/; short for "condensation trails") or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets. If the air is cold enough, this trail will be comprised of tiny ice crystals.[1]

          The wingtip vortices which trail from the wingtips and wing flaps of aircraft are sometimes partly visible due to condensation in the cores of the vortices. Each vortex is a mass of spinning air and the air pressure at the centre of the vortex is very low. These wingtip vortices are not the same as contrails.

          • And you missed the point, in which the GP was saying that the article has nothing to do with contrails, it is about a whole different phenomenon altogether.

            You shall be now asked to leave the shaolin temple, and leave your geek card at the exit...

            • And you missed the point, in which the GP was pointing out the exaggerated degree of pretention in the GGP post. Somebody accusing others of making wrong statements and telling them they should read more, in a very condescending tone, should take care not to make mistakes against the very reading material he was refering to (wikipedia, "contrail"). Of course the part about cloud seeding being a different phenomenon was correct, but that does not mean you can't react on any other part of his post.
    • Oh shut up about your tax money. Your share of their funds is probably less than 1 dollar per year, for valuable research.
    • by MacTO (1161105)

      While the majority of passengers use jets, it wouldn't surprise me if more than half of the planes in the air use that "darn near extinct" technology. You just won't see many of them at a typical international airport for reasons of economy.

      (Where are they used: flights that serve smaller communities, short haul flights, transporting goods or doing exploration in remote areas, etc..)

    • by dave420 (699308)
      Turboprop engines are used all over the world, in very large numbers. The US military alone has over 2,421 active aircraft with propellers (not including helicopters, before you ask).
      • by Osgeld (1900440)

        see how much better that sounds over "propeller jetliner"

        • by dave420 (699308)
          What are you talking about? You claimed propellers are nearly extinct, but clearly they are not.
        • by MacTO (1161105)

          Very few people will even understand the word "turboprop", so writers end up using terms that their readers will understand.

          • Which is kind of silly, given that the internet is right there to look things up, turboprop is very well defined. Whether turboprop craft are jetliners appears to be ambiguous. It looks like probably not, but I have nothing to be certain.

  • Jetliners do not have propellers. ;)
    • by blair1q (305137)

      They sort of do, in the form of turbofans in their ducted engines.

      However, these do not cause cooling. They cause enormous heating. But they cause turbulence in the air behind the plane. This turbulence may constitute enough of a difference in density and pressure to cause water vapor in the air to condense into mist, which is called a contrail.

      Airplanes also have wings and control surfaces. Air flowing over these creates vortices. These vortices can constitute enough of a difference in density and pre

    • and turboprops are both a jet and a propeller

  • Before the 2010 airplane crash that killed Polish president several top generals and tens of top politician, a mystery fog appeared. Could the fog be intentionally formed the Russian airplane that was flying around that place earlier?
    • by Wyatt Earp (1029)

      Or it was just a fog.

      http://en.wikipedia.org/wiki/Fog#Characteristics [wikipedia.org]

      Fog forms when the difference between temperature and dew point is generally less than 2.5 C or 4 F

      "Fog can form suddenly, and can dissipate just as rapidly, depending what side of the dew point the temperature is on. This phenomenon is known as flash fog."

    • by amorsen (7485)

      Mystery? What exactly was mysterious about it? Are all fogs mystery fogs?

  • by couchslug (175151) on Friday July 01, 2011 @08:16PM (#36638772)

    "commercial and private jetliners" "When an airplane flies through a cloud, its propellers"

    The number of jetliners with "propellers" is mighty fucking few, though not zero.

    Linking to the PARENT Science Daily piece

    http://www.sciencedaily.com/releases/2011/06/110630142835.htm [sciencedaily.com]

    instead of the pointless Inhabitat bullshit summary would have been nice. There is NO excuse for the Inhabitat link other than SPAM.

    AC is anonymous because he/she/it wants page hits for Inhabitat.
    Now I know not to visit Inhabitat again. Fuck you too and thanks for nothing.

    http://www.sciencedaily.com/releases/2011/06/110630142835.htm [sciencedaily.com]

    • by sphealey (2855) on Friday July 01, 2011 @08:49PM (#36638940)

      > The number of jetliners with "propellers" is mighty fucking few, though not zero.

      The number of airliners with gas turbine engines that turn propellers is in fact quite large.

      The bypass fan of a high-bypass turbofan engine is essentially a propeller as well, although ducted.

      So that leaves us with the various 707s, DC-8s, and 727s and their military equivalents flying around out there with straight turbojet engines having no fan-push component, which is not all that many in 2011.

      sPh

      In any case the results of this study should have been blindingly obvious to anyone living in North America during the no-fly week of 9/11 - 9/18.

      • by couchslug (175151)

        Technically quite correct, but few readers not greatly interested in aircraft will get those differences between a conventional external "prop", turbojets, and turbofans. I'm prior avionics/engines/crew dog (cross-training was fun) but try to keep it simple for layfolk.

        These are kinda neat:

        http://www.popsci.com/technology/article/2010-03/naked-engine-cleaner-flights [popsci.com]

    • I've never been to inhabitat but holy shit did it want to run a lot of javascript. Like 15 different domains.

  • by JayTech (935793) on Friday July 01, 2011 @08:36PM (#36638874)
    I remember reading this at a popular news site over a year ago. Where could it have been? Oh, wait, here it is! http://science.slashdot.org/story/10/06/15/2020240/Airplanes-Unexpectedly-Modify-Weather [slashdot.org]
  • ...of this? I used to wonder about this as a kid at least 15-ish years ago. Even without the stuff about propellers and pressure and such, it seemed obvious that a plane flying through a cloud would set off a reaction from the larger water drops formed from the condensation buildup on the body of it. Said larger drops fall off and through the cloud further causing a reaction.

    Of course I never studied it or took it further, so it is quite possible I am wrong, but the point stands that I thought of it long ag

    • by AHuxley (892839)
      The Airline industry was subsidised, nationalistic and futuristic. Nothing was going to be allowed to get in the way of its expansion.
      If decades of “tombstone technology" (when there are enough tombstones the technology gets fixed) was allowed to slip whats a bit of weather changing :)
  • Yeah, those private jets over the poles, why DO THEY DO IT??? Stop private planes flying over the poles. All zero of them.

    And as others have mentioned, yeah "propellers" on the "jetliners". LOL! Sure.

    I would rather blame rich guys with long noses who were originally made of wood.
    Sure, it's Pinnochio. Just as real.

    Looks like Slashdot let another potsmoker start a thread.

    E

    • by amorsen (7485)

      Looks like Slashdot let another potsmoker start a thread.

      It looks more like "let another potsmoker comment on the article" to me. Planes fly quite far north when they fly e.g. between Europe and North America, and practically all jet planes have fans -- propellers with many blades.

    • by tomtomtom (580791)

      Yeah, those private jets over the poles, why DO THEY DO IT??? Stop private planes flying over the poles. All zero of them.

      Actually, since the end of the cold war (and with the development of aircraft which can do VERY long non-stops like the A340) several commercial passenger flights operate every day which directly cross the North Pole. Particularly these are the very long East Coast US to Asia routes, eg EWR-HKG, JFK-HKG, JFK-PEK, ORD-PEK etc. In the opposite direction it's not usually done as it's more efficient to use the jet stream over the North Pacific.

    • by Misagon (1135)

      Most routes between Europe and northern Asia (Japan, Korea etc.) go over the North Pole. Many make a short stop in Alaska. The routes may look weird on a flat map, but not so much on a globe.

  • The question i always have, and never get the answer to, when I see articles about these "studies" is: explain droughts in California over the past 30 years. California has a whole lot of air traffic all over the state and yet it goes multiple years on end with very little rain. If this happens so consistently to conclude there's a correlation why does California have droughts...like ever...?

  • We run up into the sky so deep, it be crying. Yeah, you thought that was rain. http://www.youtube.com/watch?v=IU7VTJA0dNo [youtube.com]
  • FTFA "When an airplane flies through a cloud, its propellers cause the expansion and cooling of the air behind them which can cause water droplets to spontaneously cool and crystals to form." However the picture shows a jet aircraft which if very different from a plane that has a standard propeller on the front. If the study took into account the differences between the two types of aircraft I'm reasonably sure that the effect would be different. Ergo there is a significant difference between a standard pr
  • interesting. noctilucent clouds [spaceweather.com] have also been on the rise during the period of modern aircraft, and are also seen primarily towards polar latitudes.

  • Several issues over this.

    There's only one comment on the source website (and I'm not minded to sign up to the site to comment there) :
    lazyreader says:
    Would that be so much of a problem in drought prone areas?

    Which is a perfectly good question, but begs the follow-up question of "what about the marginal or drought-prone areas downwind of your seeded area, where your seeding accidentally or deliberately wrings the water out of the clouds, so these areas get tipped into full-blown drought?"

    I'm also somew

"Never give in. Never give in. Never. Never. Never." -- Winston Churchill

Working...