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Science

Airplanes May Affect Weather Patterns 51

Posted by timothy from the such-a-little-thing dept.
blankmange writes "Wired is carrying an interesting piece: '...for three days starting last Sept. 11, meteorological researchers were presented with just such an opportunity when the FAA grounded commercial flights nationwide for three days following the terrorist air attacks. And now it has emerged that the American climate was indeed noticeably different during those three days without air travel.' Seems that what we do on the planet may have more effect than we may ever know."
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Airplanes May Affect Weather Patterns More

Airplanes May Affect Weather Patterns

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  • Seems that what we do on the planet may have more effect than we may ever know.

    Of course we have an effect. The question is, is that effect positive, negative, or chaotic. I suspect it's chaotic. Three days worth of data is surely not enough to do anything but convince everyone that what they originally suspected was already correct.

  • After going to school in Manhattan, NY, I suspect buildings of being far worse. The wind is channelled between buildings and is much worse than outside the city.

    Also, in the summer almost all of the buildings have A/C running full throttle. I think all of the waste heat that is blasted outside ends up raising the temperature an appreciable amount.

    Also, the city is filthy. There are rats and cockroaches everywhere, and people are so mean.

    • Re:buildings (Score:2, Informative)

      by HeyLaughingBoy ( 182206 )
      Also, in the summer almost all of the buildings have A/C running full throttle. I think all of the waste heat that is blasted outside ends up raising the temperature an appreciable amount.


      Actually the streets have a greater effect. Power sources and the huge amount of blacktop (streets) absorbing the sun combine to create a "heat island." I took a meteorology course long ago and we learned that the temp over NYC was usually about 10F higher than the surrounding areas. It definitely has an effect on weather. Around here, it's been noted that the temperature differential of the city causes some storms to be deflected slightly as they go past.
      • I used to live in NYC. The urban heat island effect is most noticeable on summer nights. During heat waves the nighttime temperatures can be as high as 93 F at 1 AM and lows may reach only the upper 80's.

        All this at almost 41 degrees north latitude!

        NYC also gets substantially less snow for the same reason.

      • Re:buildings (Score:3, Interesting)

        by Bonker ( 243350 )
        Around here, it's been noted that the temperature differential of the city causes some storms to be deflected slightly as they go past.

        I live in Amarillo, TX. While we're certainly nowhere near the size of NYC, we do have an interesting condition that exaggerates this effect.

        Amarillo (pop ~= 300k), you must understand, is an island of glass, concrete, and asphalt surrounded by nothing but flat prarie and even flatter pasture for a distance of at least 150 miles in any direction. The only major body of water any where near the city is more than 50 miles away.

        Therefore, it is noticably hotter and windier inside the city than outside. While we do have severe weather being on the lower end of tornado alley, it tends to 'part' around the city. The last damaging tornado we had (You may have seen it on CNN since it killed a couple people) was listed as striking 'near' Amarillo. What really happened was that the tornado ran through the tiny burg of Happy, TX, which is very nearly forty miles to our south. Then, when it started aproaching the city of Amarillo, it veered off and started heading Southeast rather than Northeast. The bulk of the storm itself did the same thing... Head northeast until it came up against Amarillo, and then push off to the southeasth.
        • ... and a very poorly understood one, at that. Urban areas do tend to create what one might consider shallow, localized fronts.

          It's well known that any atmospheric boundary can have effects on a storm, both in motion and intensity. It's also well-known that urban areas do have localized differences compared to their environment.

          But it's not well-known what the overall effects might be. Severe thunderstorms are creatures that require moisture and the energy condensing it provides. In an urban heat island situation, the temperature is often higher, but the amount of moisture is only marginally higher. This actually tends to reduce the CAPE (Convective Available Potential Energy) of the urban area compared to its immediate environment. Also, the boundary of the urban heat island may act as a sort of "guide" for the storm to propogate on, much like fronts and outflow boundaries (cold, moist air from previous thunderstorms) often act.

          But, the storm is also affected by the upper air steering flow. There's a certain slaving between the upper and lower levels that is beneficial to storm development and intensification. An urban heat island may modify this enough to make a difference... that much is possible.

          However, in the case of your storm switching direction, that's actually a pretty common feature of tornadic storms, i.e. to change direction and move to the right of their previous movement vector. The dynamics of right-moving supercells (as they are called) are fairly well understood and widely accepted. So, to say that the storm turned strictly because of the city, in this case, is a little hard to believe. But, it's something that bears watching.

          And I have noticed that "effect" of cities before. It does seem to be relatively common, as a sort of informal survey... but I'm not aware of any study that's fully addressed it yet.

          -Jellisky

  • Alternative? (Score:2, Insightful)

    by ghoul ( 157158 )
    Granted Air travel probably has some effect on he environment but do we really have an alternative?

    I recall a similar debate about Supersonic passenger planes with the idea that jet engines especially supersonic jets damage the troposphere with the result that the Concorde flies on limited routes (Not that it stops the military from making hundreds of supersonic jet flights every day)

    Even if we thought maybe the commuter flights could be replaced with high sped trains what about long distance flights? I recently flew from Cyprus to Toronto and God how I wished they had a faster plane. With a 10 hour stopover at Frankfurt and trips to and from the airport I was travelling for over 30 hrs! (In coach !!!)

    Faced with that most people dont give a damn if the aircrafts damage the atmosphere as long as they get them there FAST!

    Coming back to the trains option though it works very well in Europe and Japan ; I dont know how well it would work in the States where people are used to doing things there own way and not handing over control. I say this because with trains it really is not economical to have competition- trains are feasible if u have only one set of tracks in a route and everyone uses it. In order to avoid a monopoly it would have to be run by the Fed Govt. and I dont know how many people will like that.

    Just a few thoughts....
    • But AmTrak [cnn.com] is great!

      Isn't it?
    • How about hydrogen powered jets? The exhaust would be water vapor.

      • Re:Alternative? (Score:3, Interesting)

        by dschuetz ( 10924 )
        How about hydrogen powered jets? The exhaust would be water vapor.

        It's my understanding that contrails aren't smoke from the jets, but are ice crystals formed in the chaotic vorticies of air spinning off wings.

        That is, the high-speed wing creates even higher-speed whirlwinds, and the moisture in the air, when caught in these whirlwinds, freezes, leaving an opaque white trail.

        I'm guessing that these "expand" into large cloud banks less by spreading and thinning than by catalyzing the creation of more clouds in adjoining air -- the frozen moisture cools the air around the contrails, and can cool it just enough to allow more clouds to form, etc., etc.

        Of course, I'm just pulling all this out of my butt -- will a real meterologist please stand up?

      • Re:Alternative? (Score:2, Informative)

        by ghoul ( 157158 )
        As far as I know besides the NOX emissions at high altitude the problem was also that high speeds create Ozone due to heat which leads to ground level Smog (Note Ozone very High Up-Good; Ozone Ground Level/Stratosphere -Bad)

        The problem of high speeds creating ozone would remain even if we used Hydrogen jets
    • Granted Air travel probably has some effect on he environment but do we really have an alternative?Humanity has lived on this planet for thousands of years without cars and airplanes. Why the smeg all of the sudden does everyone need to fly every fucking where?

  • Vulcanoes and stuff (Score:2, Insightful)

    by skilef ( 525335 )
    Scientists have been pretty busy with studying the effect vulcano-eruptions have on the climate. Couldn't it be possible all the dust and smoke of the WTC, Pentagon and crashed plane have a similar effect to a lesser extent?

    • Re:Vulcanoes and stuff (Score:3, Informative)

      by shrikel ( 535309 )
      The amount of dust and debris that were thrown into the air on 9/11 was far, FAR too little to have a significant impact on the climate. (Other than the chaotic butterfly effect, of course.) Compared with some of the larger volcano eruptions just in RECENT history, the WTC dust was just a cup of water compared to all the water in the Great Lakes.

      I don't know what the short-term, localized (to NYC) effect it had. Probably measurable, but certainly not widespread.

      • Very good point.

        However, the article was focusing on the lack of planes in the air because of the attack on 9/11. Never have modern meteorologists had the opportunity to study weather patterns in conditions without airplanes because we have been flying planes longer than they have been studying the weather!

        As for:
        "I don't know what the short-term, localized (to NYC) effect it had. Probably measurable, but certainly not widespread"

        As the chaotic butterfly demonstrates, everything is widespread.

        • However, the article was focusing on the lack of planes in the air because of the attack on 9/11. Never have modern meteorologists had the opportunity to study weather patterns in conditions without airplanes because we have been flying planes longer than they have been studying the weather!

          Longer than we've been studying weather? Well, longer than most scientists alive today have personally, anyway. ;)

          But I agree with some other posts, which remark that three days without airplanes is not enough statistically (scientifically) to show ANYTHING conclusive about their effects whatsoever. If we could study it for a year, it would give us at least something to go on, but three days is not nearly enough to accumulate enough meteorological data to do anything useful with.

          As the chaotic butterfly demonstrates, everything is widespread.

          I was referring to direct short-term effect, not chaotic, long-term effect.

    • The problem with volcanoes, as far as I understand, is that the ashes are propelled quite high in the atmosphere, and thus can spread far and wide, sometimes thousands of kilometers away. Debris from the WTC probably did not go further than a few blocks. I don't think it makes sense to put the explosion of a building, even a large one, in the same category than a large volcano.

      Also, large buildings are blown up all the time when they are demolished - albeit usually there are no people inside. But from the meteorological point of view, it proably makes little difference.

  • Nothing new (Score:2, Interesting)

    by labtec6 ( 443718 )
    This really isn't anything new.

    Besides the fact that 3 days is too little to check, it has been studied and theorized how butterflies in Africa, or bats in Brazil can cause chaotic effects on the weather.

    Mountains, trees, ducks, all cause effects on the weather. There are a lot more birds and bats in this world than planes. They probably have a larger effect on the weather than planes do.

    If we really wanted to see how planes effect weather patterns, we can always try to go to another planet (Mars, is a good choice) and study their weather. Mind you, trying to get air planes to Mars would be a real pain to test this theory.
    • Mountains, trees, ducks, all cause effects on the weather. There are a lot more birds and bats in this world than planes. They probably have a larger effect on the weather than planes do.

      Um, ducks don't leave contrails. Did you even read the article? The contrails left by the few military transports up at the time started out no wider than the airplane's wing, but in a few hours had become clouds covering 20,000 square Km. Repeatedly. This had never been noticed before because those skies were usually crossed by hundreds of flights, not ones and twos.

      We have had a glimpse at how planes affect the weather. It is very interesting- they are not necessarily damaging it, but it has become quite obvious that they do affect it. Now it's something we have to keep in mind and keep an eye on.

      • I should have made myself a little more clear. And I did read the article, BTW.

        I was refering to the fact that planes do affect the weather, but there are many things that have a greater impact on the weather. Cities have a huge impact on weather systems that pass through their areas, with all the concrete and ashphalt that radiate heat back into the air, especially at night after the sun has gone down.

        Contrails on an aircraft do create artificial clouds, which I find very interesting, but if anyone has looked at contrails of high flying aircraft, they stay around, and spread out. To me, this article was nothing new.
    • it has been studied and theorized how butterflies in Africa, or bats in Brazil can cause chaotic effects on the weather.

      It has? I'm not so sure about that...

      Although, that would be pretty funny. "Yeah, well, we noticed that whenever that group of bats in Hyderabad go apeshit and start flying in circles, it snows in Toledo."

      • Theorized and studied in mathematical models, yes. In actual "lets go make a butterfly do this, and see what happens over there", probably not.

        Anything and everything possibly do cause weather patterns to change slightly. Mind you, even I would like to see how much butterflies and bats do change weather patterns. Probably only a little bit but it can add up over time.

  • Well, great, I say! (Score:3, Funny)

    by msouth ( 10321 ) on Wednesday May 15, 2002 @10:48AM (#3523321) Homepage Journal
    Because that should really decrease the load on the butterflies.
  • I thought that guy was crazy when he blamed weird weather on planes. He said, "The weather was a lot better around here before they started flying all those damn planes everywhere!"

    Wow, what a genius.
  • Living in Minnesota( The evil fridge of the US ) you quickly learn that the winter temp drops less at night when it is cloudy.

    So you would guess that artificial coulds( Contrails ) would do the same thing.

    Still an interesting opertunity. Lets hope we don't have the opertunity to study this agian.

  • Ultimate excuse ??? (Score:3, Funny)

    by Guignol ( 159087 ) on Wednesday May 15, 2002 @11:32AM (#3523569)
    Yeah right....
    No really, we do have very precise weather models...
    That supercomputer we made you buy not only gave us a 280 fps boost at Q3A, but it also allows us to predict rain, temperatures very precisely anywhere on the globe for the next 20 years to come with .2% error only...
    We can even predict where lightnings will strike and when...
    It's those damn planes that invalidate everything...
    Of course, we did include them in the model, but neither TWA nor any other airline respects its schedule.. that makes our task much harder...
    Perhaps with an even more powerful supercomputer...
    • neither TWA nor any other airline respects its schedule.. that makes our task much harder...
      Perhaps with an even more powerful supercomputer...

      No, I think what we need here is a law.

      -

  • Rule #1 of Scientific Research... (Score:1, Insightful)

    by Anonymous Coward
    Correlation != Causality

    Just because two events occur at the same time doesn't mean one is the cause of the other.

  • clouds [contrails] and their effect on climate (Score:5, Informative)

    by dolsen ( 578046 ) on Wednesday May 15, 2002 @01:23PM (#3524317)
    here's a nice image [nasa.gov] that illustrates (from low earth orbit) contrails over a large area (Nova Scotia, Canada, to be exact). at the NASA rapidfire site [nasa.gov] [bandwidth intensive] you can basically pick any day, choose an image over the northeast of the US [approx. 15:00 to 16:00 UTC normally] and it's a good bet you'll see lots of contrails. they have to have some impact on at least the local climate of the northeast. if you're in the mood for some light reading you can check out several NASA reference articles about clouds and their affect on climate:
    • Changing Global Cloudiness [nasa.gov] Clouds are visible collections of small particles of water or ice, or both, suspended in the atmosphere. They are one of the most obvious and influential features of Earth's climate system. They are also one of its most variable components.

      Aerosols and Climate Change [nasa.gov] Aerosols are tiny particles suspended in the air. Taken as a whole these particles tend to cool Earth's atmosphere, and are an important factor in global change.

      Clouds and Radiation [nasa.gov] The study of clouds, where they occur, and their characteristics, play a key role in the understanding of climate change. Whether a given cloud will heat or cool the surface of the Earth depends on several factors.
    there's also a good page on how ship tracks [nasa.gov] affect climate

    oh yeah, the NASA press release [nasa.gov] about the contrail study...
    • there's also a good page on how ship tracks [nasa.gov] affect climate

      The ship tracks refered to above are those from a steam stack. Similarly, I've thought it interesting just how large the wake of a large boat can be - a different kind of "ship track".

      Flying over the greats lakes I've seen large tankers (I presume) with wakes that seem to extend half way across the water, dwarfing the size of cities on the shore (downtown Toronto for example).

      I doubt such wakes have much of a material impact on large weather systems (perhaps more than a butterfly though). But could they have local effects or an impact on erosion?

      At the very least, they are interesting as very large and temporary man-made "structures" that certainly (if only visually) impact on our environment.

  • Okay... some thoughts on all this... (Score:4, Interesting)

    by jellisky ( 211018 ) on Wednesday May 15, 2002 @05:29PM (#3526002) Journal
    First of all, my biggest pet peeve: the difference between weather and climate. Yes, believe it or not, climate and weather are two very different terms. They should not be used interchangably, thankyouverymuch. Three days does not a climate make.

    Now, to continue on that thought, it's interesting to think about the consequences of this "study". (The quotation marks are supposed to be there.) I cannot say what I really think of this "study" since I haven't read their results, but I cannot be that easily convinced that three days worth of data compared to years worth of data has any possible statistical significance, especially in something like diurnal ranges, which are 15-30 degrees C anyways. Show me three months and I might be convinced of a trend. I can name at least 10 different three-day weather features that could cause such a blip and that's just off the top of my head.

    Next, IF this is true, then it only highlights something which has bothered me about climate modeling from the frickin' beginning: the role of clouds and how terribly they are handled in these (and all) models. Of course, this isn't the only problem I have with these modeling studies, but we won't enter that debate right now.

    The type of cloud present has an effect on the net change in radiative flux. Deep, thick clouds (like cumulus) have a net positive change while thin clouds (like cirrus) have a net negative change. The thing, though, is that in balance calculations like these, there tend to be two effects, which are approximately equal and opposite in sign. So, you end up wondering how much of it is really real. (For example, the two terms might be 220 and -218, leading to 2 change... but if you're off by a little bit, those numbers might actually be 219 and -220, leading to a -1.) This is further compounded by the way models handle clouds, which is often routinely terrible (with respect to resolution, the actual physics involved in the cloud which can affect all the results, and many other factors).

    To further put all this in perspective, let's assume the albedo (the amount of solar radiation reflected back to space by the earth which is largely a function of the cloudiness) of the earth increases by 1%. (It's currently around 30% in a climatological sense... even that number has an error bar of measurement around +/- 3%.) On average, that would mean that the earth would get 3.4 W/m^2 less radiation. (Daily and spacial average of solar radiation is about 340 W/m^2, again largish errors on this measurement.) This number is comparable to the change by doubling CO2 (about 4 W/m^2) and, as you can notice, opposite in sign. Of course, there's a huge extra batch of physics here that isn't even being considered like the change of the absorption of IR radiation from the earth by the clouds or the release of latent heat by the clouds or the feedback between warmer surface temperatures and clouds (which is barely understood since it's almost as complex a problem as the original)... Kind of makes your head spin to think about all these effects, doesn't it? And all of them are about the same order of magnitude by itself, i.e. about 0.5-5 W/m^2, both positive and negative. Let's also not forget that local effects, like all those new urban heat islands that have popped up around all our temperature recording stations that could very well explain that temperature rise in the last century or whatever, and that these effects are not put into these models...

    Complex problem? You bet. Possible to understand? Eventually, I don't see why not. But, we can't sit back and keep using these antiquated ideas in these state-of-the-art models. As the old saying goes, "Garbage in, Garbage out." The effects of these contrails may be important, yes. I cannot debate that. However, to claim that off of whatever insignificant sample this is, or using any of the ideas we currently have, is ludicrous at best. Any imbecile with a computer nowadays can run a correlation analysis on data. But, to interpret it and explain WHY things are happening that way... that's the vital connection between statistical tomfoolery and real science. Then, to explain the dynamics and theory behind it all... that's the step to making a full fledged theory.

    -Jellisky
  • Was anyone reminded of the suggestion that a single butterfly could change weather patterns when they read this?

  • More data? (Score:3, Insightful)

    by Debillitatus ( 532722 ) <devillel2&hotmail,com> on Wednesday May 15, 2002 @06:34PM (#3526349) Journal
    Of course, I'm sure my fellow /.ers are posting about the paucity of data in this sample. So, I won't worry about the fact that we can't derive too much useful information from this.

    OTOH, I imagine that the air traffic, in, say, the US varies quite a bit from day-to-day. For example, the day before Tgiving is berzerk, and there's probably some days where noone travels. Anyway, one way to get more data on this theory would be to correlate, over a long time, the cloud (or whatever) variables with the number of planes in the air. Do this every day for about a year, and see what you get.

    One thing to note is that although these three days are not much data, it's actually very strong, in the sense that nothing flew those days. So it's the strongest data you could get over any three-day period. I'm sure we'll see more stuff coming out soon.

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