Stories
Slash Boxes
Comments

News for nerds, stuff that matters

Slashdot Log In

Log In

Create Account  |  Retrieve Password

Zapping Contrails With Microwave Emitters

Posted by timothy on Thu Nov 20, 2008 05:12 PM
from the set-it-for-beverage dept.
An anonymous reader writes "Dissipation of contrails with a powerful microwave beam aligned behind aircraft engines is being touted as a possible solution to help address air transport's effects on the climate. 'The remote heating of condensation nuclei could be achieved by applying electromagnetic radiation, such as microwaves,' says Cranfield University's Frank Noppel. 'Depending on assumptions made, calculation shows that the power required for such a device could be as little as 0.1% of the engine power.'"
+ -
story

Related Stories

This discussion has been archived. No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
 Full
 Abbreviated
 Hidden
More
Loading... please wait.
  • I'm confused (Score:5, Interesting)

    by stoolpigeon (454276) * <bittercode@gmail> on Thursday November 20 2008, @05:15PM (#25838559) Homepage Journal

    My understanding was that contrails contribute to global dimming and are helping to keep temperatures down. If I read the article correctly, this would not remove any pollution, just remove the clouds and allow temperatures to be even higher. Reading it made me think that the goal has become to have no impact on climate at all - positive or negative. That doesn't seem right, so I think maybe I'm missing something.

    • Re: (Score:3, Funny)

      No, they're doing us a favor by zapping them so that the government mind-control chemicals will no longer effect us. c.f. "They Live" =D
      • Rather horribly, I know a girl who believes that to be true - in fact, she thinks "They Live" is a sort of documentary thinly veiled as fiction. Not only is the government dropping stuff from high altitude jets onto its citizens, but it's also under the control of the Illuminati (she uses that word). Everywhere we go, she points out signs that the Illuminati are controlling us.

        Last I heard, she was moving to a rural area to buy land and build a "compound" (again, her term). Even scarier is the fact that she

        • I can see where her beliefs actually some from. After all, the government did spray biological chemicals with specific markers in the from the skys between 1992 and 1999. Of course this was to check for the spread of a chemical or biological attack and the effects on the populations. I believe at one time, they actually use the common cold as the chem.

          This happened across most of the free world to be exact and it started in other areas back in the late 80's as part of a weapon's defense program. It turns ou

      • Re: (Score:3, Interesting)

        No, they're doing us a favor by zapping them so that the government mind-control chemicals will no longer effect us. c.f. "They Live" =D

        I'm glad someone finally had the courage to get the ball rolling on this [wikipedia.org]. Sir, I applaud you for bringing this very real [worldaffairsbrief.com] issue to light. Often times I wonder [luxefaire.com] why the relationship [conspiracyarchive.com] between the pharmaceutical industry [psorsite.com] and secret government [meta-religion.com] organizations [mormonconspiracy.com] isn't more apparent to "normal" [aliendave.com] people.

      • by neomunk (913773) on Thursday November 20 2008, @08:04PM (#25840511)

        Zapping them so that they no longer effect us? Pssh, my source says that the microwaves are needed to ACTIVATE the next generation of chemically generated complacency.

        Then again, the same guy swore Ron Paul was going to win the popular vote...

    • Your understanding is flawed.
      • Re:I'm confused (Score:5, Informative)

        by Roland Piquepaille (780675) on Thursday November 20 2008, @05:38PM (#25838921)

        No it isn't. Studies have shown that temperatures rose significantly across the US right after 9/11 when all planes where grounded for several days, because of clearer skies.

        See here. [berkeley.edu]

        • Probably due to all the politicians venting off a bunch of hot air. What is the thermal density of rhetoric and impotent american outrage?

          • Re: (Score:3, Insightful)

            Correllation != Causation

            however: Correlation != Causation unlikely/impossible

    • Re: (Score:3, Interesting)

      Vapour trails or contrails, by affecting the Earth's radiation balance, act as a radiative forcing. Studies have found that vapour trails or contrails trap outgoing longwave radiation emitted by the Earth and atmosphere (positive radiative forcing) at a greater rate than they reflect incoming solar radiation (negative radiative forcing). Therefore, the overall net effect of contrails is positive, i.e. a warming.[2]

      Wiki [wikipedia.org]

      Kinda sounds like BS to me... They are somehow different from normal clouds in that they

      • Re: (Score:3, Interesting)

        > Kinda sounds like BS to me...

        It isn't.

        > They are somehow different from normal clouds in that they trap more heat than they reflect?

        No, they are like normal clouds. Some clouds reflect more heat than they trap, some trap more heat than they reflect. Contrails are like the latter.

        • We should microwave _all_ the bad kinds of clouds then.... what could go wrong?

        • Re:I'm confused (Score:5, Informative)

          by ceoyoyo (59147) on Thursday November 20 2008, @06:06PM (#25839263)

          From the wiki article it sounds suspiciously like contrails have a warming effect when they're produced either a) at night or b) during the winter. From the percentages listed, it appears that the contrails may well have a cooling effect if they're produced during the day and/or not during the winter. That makes the assertion that the net effect is heating a little easier to swallow.

          No, I didn't check out the typically mangled Wikipedia reference. Seriously... citations are great, but you use journal abbreviations and short form references when you're trying to cram them onto one page abstracts, NOT when you're putting them on web pages where space is free.

              • Re: (Score:3, Informative)

                Sorry, now I see. I thought you meant that the citations should be in the article. The abbreviation was probably copypasted from somewhere, though. For the interested, it's Geophysical Research Letters 32 (2005).
      • Not to mention a little extra CO2 from the 0.1% extra fuel that needs to be burned to power the microwave. And the extra fuel needed to carry the thing.

    • by SuperBanana (662181) on Thursday November 20 2008, @06:04PM (#25839233)
      ...not the contrail itself. Jets release huge quantities of "unburned hydrocarbons, particulates, sulfates, nitrogen oxides (NOX), and carbon dioxide" (link [csmonitor.com].) This cute little idea will do shit all to help that; it's just a bit of theatrics to make it look to the eye like there is less pollution.

      Remember how in Sim City an airport would dramatically increase pollution for your city? Yeeeeeah, it isn't far from the truth. Airports aren't transportation hubs; they're giant kerosene burners, which is why the air absolutely stinks for miles around. I seem to recall reading that one 747 during takeoff creates more pollution than a Toyota Prius will in its entire serviceable lifetime. Obviously you can't use microwaves at any kind of intensity during taxi, run-up, or takeoff, as the ass end of the plane is facing near or at the ground.

      Also, it's pretty famous now, but someone studied the weather records around September 11th, 2001 and found there was a remarkable change in the weather across the country and in fact much of the world on the few days that followed where there was very little in the way of air traffic (and another change back to "normal" when air traffic resumed.) Ask most people and they remember it being rather nice out. I remember the weather in lower NY was absolutely spectacular for several days- beautiful blue skies like I'd never seen before in that part of NY.

      • I remember the weather in lower NY was absolutely spectacular for several days- beautiful blue skies like I'd never seen before in that part of NY.

        Just wanted to note that I experienced the same thing, but have a couplre observations:

        Do you recall the weather on 9/10/01 and the morning of 9/11/01? Absolutely gorgeous, nice shore breeze so we had clean air, sunny, and low humidity. I'm not sure if the weather subsequent to 9/11 was part of the same weather pattern or not, or how much impact reduced air t

    • It makes sense to me - mornings are always warmer if the night was overcast, at least where I live.
    • Ya, I'm still working on how warming the exhaust of a jet is going to "Help" global warming.?

    • Who cares about temperature? I just want to see clean blue skies again. There was only one week in my life when I didn't see jet contrails in the sky, and while I was able to appreciate the beauty, knowing why the beauty existed made me feel a little guilty.
  • Logic abounds! (Score:4, Informative)

    by MaxwellEdison (1368785) on Thursday November 20 2008, @05:35PM (#25838871)
    Reduce the atmospheric warming effect of contrails by microwaving and thereby heating the atmosphere...

    Dare I say...BRILLIANT!


    Actually, I wonder what effect this would have on those pesky naturally occuring clouds...
    • Reduce the atmospheric warming effect of contrails by microwaving and thereby heating the atmosphere...

      Actually they are cooling: they reflect sunlight back into space and produce global dimming which counteracts the greenhouse effect. There was a study done comparing day-night temperature differences over the period around the 11/9 attacks when air travel was grounded over the US that suggested air travel had a significant contribution to global dimming.

      Of course it is still a stupid idea: reduce global dimming which offsets the greenhouse effect by burning more fuel which makes the greenhouse effect wo

      • There's debate about that. And, like anything related to climate change, if there is debate ongoing we must begin implementing the idea immediately.
  • by frovingslosh (582462) on Thursday November 20 2008, @05:39PM (#25838943)
    a possible solution to help address air transport's effects on the climate........ so the "a possible solution" to those little white trails behind jets that usually dissipate quite quickly is to shoot a powerful microwave beam in the sky. What could possibly go wrong?
  • Passenger: My $8 cilantro-turkey-roll-lettuce wrap is cold!

    Flight attendant: Sir, we heated it in the microwave, but by the time we reeled it back in, it had cooled down to 30-below. Would you rather have the $9 Pepperidge Farm cookie?

  • "Microwaving Contrails" would be a good name for a rock band...

  • 0.1% is huge! (Score:5, Insightful)

    by camperdave (969942) on Thursday November 20 2008, @05:57PM (#25839139) Journal
    calculation shows that the power required for such a device could be as little as 0.1% of the engine power.

    A 747 uses four RB211 engines (or the Pratt & Witney equivalent) each of which puts out 30 megawatts of power. So this microwave contrail zapper is going to be using 120 kilowatts of power? That's 60-80 kitchen microwaves running simultaneously. That's more power than many radio stations use to transmit. I can't help thinking this will cause more problems than it solves. How is it going to affect radar, TV, cell phones, etc? How is it going to affect other planes on the same flight path? How is it going to affect the moisture already in the air? What's going to happen when one of these aircraft come in for a landing and forgets to turn off their contrail zapper?

    It's probably money a lot better spent trying to build cleaner burning engines in the first place.
      • "Contrail" is short for "condensation trail" ... which is primarily water vapor. I doubt making the engine cleaner would reduce the trail.

        Um... the water vapour condenses around soot particles in the engine exhaust.
      • Contrails are water vapour in the same way that smog is water vapour, ie: water vapour mixed with hundreds of other chemical compounds. A jet engine basically dumps a stream of kerosene into a can with a fan on both ends and lights it. There are no emissions controls. There are no catalytic converters. Aviation fuel is a witch's brew of paraffins, olefins, naphthenes, and other hydrocarbons, plus anti-oxidant, anti-corrosion, anti-static, anti-freezing, and even anti-bacterial ingredients thrown in. Th
  • by vrmlguy (120854) <samwyse&gmail,com> on Thursday November 20 2008, @06:02PM (#25839203) Homepage Journal

    Jet contrails apparently serve to cool the Earth during the day, as they reflect solar radiation, while at night they serve to warm the Earth, by trapping heat. So for maximum effect, you'd want to only dissipate the contrails created during nighttime flights. This would include not just "red-eye" flights, but air cargo operations like FexEx. Measurements taken during the grounding of all commercial flights following 9/11 indicate that there was a two degree increase in the range of day/night temperatures, so elimination of just the nighttime contrails could lower temperatures by a degree or so.

    http://archives.cnn.com/2002/TECH/science/08/07/contrails.climate/index.html [cnn.com]

  • Jet exhaust is already quite hot, thank you very much. Tell me how adding heat 0.1% to the 70% present in the exhaust will prevent cooling, condensation and crystalization of ice.

    Even with lonbg-range microwaves, it'll just recondense since it lost the engine turbulence.

  • It would seem the obvious reason for implementing something with such dubious prospects is to firmly eliminate one of the nasty conspiracy theories/rumors that circles around the drain of the Internet. Chemtrails.

    These are supposed to be something that results from introducing various chemicals to either the jet fuel or into the engines themselves to make for a more docile population. Or to stir things up and create race riots which can then be brutally put down. Or some other result which often the peop

    • It will be interesting to see if a trend develops of pre-cooked birds falling from the sky behind jetliners outfitted with this technology.

      Roasted fowl falling from the heavens? It's like the Bible, only I don't have to be wandering in the desert!

      Hang on...they'll be using microwaves?

      Never mind. I can get that without leaving the basement.

    • No no no... you've got it all wrong. Chemtrails are susceptible to microwave heating disbursement, but that's a GOOD thing... this way the mind control chemicals they are spreading will disperse faster and they wont need to use as much of that expensive stuff to keep the populations docile.

      They cant just implement it though because people would get nervous if the chemtrais just suddenly disappeared so they need a good public justification for the change.

    • Re:Why.... (Score:4, Informative)

      by logjon (1411219) on Thursday November 20 2008, @05:30PM (#25838803)
      http://news.nationalgeographic.com/news/2006/06/060614-contrails.html [nationalgeographic.com] Aircraft are believed to be responsible for 2 to 3 percent of human CO2 emissions. Like other high, thin clouds, contrails reflect sunlight back into space and cool the planet. However, they also trap energy in Earth's atmosphere and boost the warming effect, the study says. (See National Geographic magazine's "Global Warning: Signs From Earth.") Stuber and other scientists believe that the effect of the contrails is significant. "On average the greenhouse warming effect dominates [the effects of contrails]," said Stuber, a meteorologist at England's University of Reading.
    • WHY, in this age of "Global Warming will DESTROY the Earth" are they wasting money and effort on a way to get rid of contrails... something that is keeping us just a little bit cooler?

      Drop the solar input on a farm by a couple of degrees, and the crops don't grow as profitably. It's the same for wind power-- some downwind agriculture fear that if turbines take energy out of normal wind patterns, their farms output will be upset measurably. Remember, Global Warming is not about short-term local conditions but about overall year-round global averages. Some areas will be colder, some areas will be hotter, and chaotic conditions will be stronger. Contrails affect local areas and should b

    • The current financial market has pretty much guaranteed that they can do nothing "green."

      On the contrary, there are many 'green' innovations that are actually cost saving innovations. Look at the Boeing 787 (if it ever gets off the ground) it uses much less alluminum and has 20% higher fuel efficiency. Modern innovation is both green and economical.

        • So not having to mine and refine a few extra tons of alluminium doesn't help the environment? Reducing fuel burned by 20% doesn't reduce greenhouse gases and particulates? I'm confused by your definition of green technology, unless you mean 'technology that's only purpose is to be more environmentally friendly'. If that is what you mean, then by your definition there isn't a single major corporation that has significantly invested in green technology.

          • Wouldn't it be more "green" to not build the airliner in the first place?

            Wouldn't it use less fuel if it had never been built?

            Wouldn't the climate be helped far more if airplanes were reserved for government and military use only?

    • Re: (Score:3, Informative)

      What are you smoking?

      Define "green". If you're using it in the common manner, it means one or more of the following:

      Reduced carbon footprint
      Reduced toxin output
      Reduction of resources required to produce
      Reduction of resources required for operation

      And note that this is per unit of work, whether that is passenger-mile or some other measure of work.

      Note that while substitution of resource requirements can go either way with cost, reduction of resources for operation will by definition reduce cost.

      Maybe y