Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Airplanes Unexpectedly Modify Weather

timothy posted more than 4 years ago | from the send-me-some-snow-planes dept.

Earth 223

reillymj writes "Commercial airliners have a strange ability to create rain and snow when they fly through certain clouds. Scientists have known for some time that planes can make outlandish 'hole-punch' and 'canal' features in clouds. A new study has found that these odd formations are in fact evidence that planes are seeding clouds and changing local weather patterns as they fly through. In one case, researchers noted that a plane triggered several inches of snowfall directly beneath its flight path."

Sorry! There are no comments related to the filter you selected.

What wasn't mentioned (5, Funny)

mlawrence (1094477) | more than 4 years ago | (#32583522)

Was this plane belonged to the Mexican Cocaine Cartels, who thought they were being trailed.

Re:What wasn't mentioned (-1, Troll)

Anonymous Coward | more than 4 years ago | (#32583534)

What also wasn't mentioned was that splitting your sentence between the title and the actual body is fucking stupid. Go suck a dong, faggot.

I don't see (3, Funny)

Anonymous Coward | more than 4 years ago | (#32583598)

what's the problem {?|.}

I think the first AC (0, Offtopic)

snowboardin159 (1744212) | more than 4 years ago | (#32583958)

needs an IP ban. Lets try to keep this a titch classier.

Re:I think the first AC (1, Insightful)

Anonymous Coward | more than 4 years ago | (#32584000)

You sound new to /.

You sound even (0, Offtopic)

snowboardin159 (1744212) | more than 4 years ago | (#32584216)

newer to /. than I, or for some reason cannot seem to login you coward.

http://www.myspace.com/snowboardin159 (-1, Troll)

Anonymous Coward | more than 4 years ago | (#32584368)

Wow, what a colossal tool. Please go "snowboardin" and get crippled.

catalyst (-1, Offtopic)

conspirator57 (1123519) | more than 4 years ago | (#32583524)

and first post?

denied. (0, Offtopic)

conspirator57 (1123519) | more than 4 years ago | (#32583544)

epic fail

Cloud Seeding (3, Interesting)

illumastorm (172101) | more than 4 years ago | (#32583530)

Interesting. So the effect of cloud seeding is just as likely to be caused by the planes flying through the clouds rather than the silver iodide alone?

Re:Cloud Seeding (4, Informative)

Trepidity (597) | more than 4 years ago | (#32583578)

That was suggested back in 1970 [ametsoc.org] --- that cloud seeding experiments need to consider the possibility that the plane's flight itself is doing the seeding.

Re:Cloud Seeding (3, Interesting)

bunratty (545641) | more than 4 years ago | (#32583688)

I would think anyone who understands how to design experiments would see the need for a proper control group. If you fly a plane through some clouds and dump iodide crystals, and don't fly any plane though other clouds, what caused the difference in precipitation? Was it the plane or the iodide crystals? Didn't they carry out such a proper experiment?

Re:Cloud Seeding (3, Insightful)

Smauler (915644) | more than 4 years ago | (#32583990)

Control groups are basically impossible to find with clouds, as any meteoroligist will tell you. We still cannot absolutely predict which ones will dump rain on us, and which ones won't - often they behave in completely unexpected ways with no apparent reason why. There's no such thing as a control group with clouds, because one formation may have been going to dump a load of rain anyway, and another seemingly identical formation would not.

With a large enough control it may be possible - but getting a large control is basically nigh on impossible because of differing air temperature, atmospheric pressure, wind speed, and a whole host of other variables. This is not something you can accurately simulate either.

Re:Cloud Seeding (0)

bunratty (545641) | more than 4 years ago | (#32584094)

[citation needed]. You can easily find a control group. Simply randomly assign individuals of the population to the control group or the experimental group. This is done with people in drug trials all the time, and I would submit that people are even less predictable than clouds.

Re:Cloud Seeding (2, Informative)

apoc.famine (621563) | more than 4 years ago | (#32584242)

Sorry, but you don't know what you're talking about. There is no possible way to do any sort of control on clouds. They are all different. Trust me - I'm slogging my way through meteorology classes at the moment. I took a class that touched on cloud physics last fall.

Clouds are substantially different, and waaaaay more complicated than human physiology. We're not at the stage that we can measure the amount of water and particle sizes in clouds yet. The best we can do is fly a 3cm diameter probe through a cloud, and sample something like a millionth of it.

In fact, cloud dynamics are so ridiculously complicated that we don't even have good models for them yet. Supercomputer time sort-of gets us close to working models. The fact that nobody can reliably predict rain and snowfall amounts, nor weather more than a week out should give you some indication of the complexity of clouds.

Re:Cloud Seeding (2, Insightful)

bunratty (545641) | more than 4 years ago | (#32584334)

Yes, I do understand that clouds are all different. You simply randomly assign clouds to a control group or an experimental group. That's how you get controls. It doesn't matter how complicated clouds are -- it is trivial to get a control group. You don't seem to understand how to design controlled experiments. Please, provide a citation stating that it's impossible to perform controlled experiments on clouds, preferably with a lucid explanation for why it is so.

Re:Cloud Seeding (3, Informative)

apoc.famine (621563) | more than 4 years ago | (#32584772)

I know you think you're very smart. But you really don't understand how different clouds are, or you don't understand what a control group is.

If you were going to test a fishing lure, would you use a "control group" consisting of trout, bass, pike, baleen whales, and tiger sharks? Would you then apply the results to all "fish", despite the fact that some of those weren't fish at all? I would hope not.

This is the case with clouds.

If you'd like to know more, try Wallace and Hobbs [amazon.com] . It's one of the cornerstones of modern atmospheric science. I know you're all hip and can make fancy [citation needed] fake-wiki code, but there are some subjects you can't be an expert on just by casually reading a page on the internet. Neurosurgery and cloud microphysics are two of those things.

Cheers!

Re:Cloud Seeding (2, Insightful)

Anonymous Coward | more than 4 years ago | (#32585036)

I think the guy you are arguing with is thinking of an experiment something like this, for example. Take 1000 clouds that are at least reasonably able to produce precipitation (for instance cumulus congestus clouds, or only nimbo stratus). As the cloud appears, draw a color out of a hat. If blue, seed the cloud, if red, fly through the cloud, and if green do nothing. If 90% of the seeded clouds produce precipitation, and only 40% of the unseeded clouds do, then that is good evidence that the seeding has worked, no matter what all of the variables are. This concept is called blocking in designed experiments and can be very effective.

An easier to understand example is this. I'm testing leather A and B for shoe construction. How people use shoes is dependent on many variables, you might have violin players and rugby players using the shoes. One can't possibly design an experiment to account for all the variables, unless you randomly assign one member from a pair of shoe to have use leather A, and the other one leather B. That way each person is testing both leathers under presumably the same circumstances.

The cloud example is not nearly as efficient as the leather example above... it would take a lot more data for me to believe that seeding works, but it is an effective experimental strategy, no matter how complicated cloud physics is. My gut feeling is that the effect of seeding is small, so it would take a tremendous number of runs to be sure of the results. But if the experiment is run a thousand times, and each time seeded clouds produce more rain, don't you think that's a possible indication that the seeding works? One doesn't have to understand everything about a cloud to experiment with them, as in any field.

And yes, I'd reckon the person you are arguing with understands both what a control group is, and how different clouds are.

Re:Cloud Seeding (1)

bunratty (545641) | more than 4 years ago | (#32585430)

Yes, exactly. You could perform the test on cumulus clouds, on stratus clouds, on cirrus clouds, and on nimbus clouds. Just come up with a criterion for which clouds to try your experiment on, then randomly assign some clouds to a control group and the rest to the experimental group. Just like every other control experiment ever performed. What is it about the scientific method that's so difficult for so many to understand?

Re:Cloud Seeding (1)

Graff (532189) | more than 4 years ago | (#32585096)

If you were going to test a fishing lure, would you use a "control group" consisting of trout, bass, pike, baleen whales, and tiger sharks? Would you then apply the results to all "fish", despite the fact that some of those weren't fish at all? I would hope not.

You can still use that data as a control, you just need to properly categorize the data before you use it. Coming back to cloud formations and controls what you'd need to do is classify each cloud, control or not, and then use the data appropriately.

Observe the type of cloud, the meteorologic conditions, and other pertinent data such as season, phase of the moon, natives chanting on the ground, whatever. You then compare your clouds that have been seeded against appropriate control clouds. Yes, this means you will need to either get a lot more data or just limit the clouds you pick to certain conditions and types. Meteorological research is slow, painstaking, and time-consuming because your laboratory doesn't fit into a building and you have to do a lot more work to properly isolate all variables.a

Re:Cloud Seeding (0)

Anonymous Coward | more than 4 years ago | (#32585216)

So if I test the lures, and the first lure attracts some sort of swimming animal within 15 minutes 90% of the time, and the second lure attracts some sort of swimming animal within 15 minutes 10% of the time, I can't gain any knowledge about the effectiveness of the lures from this experiment? Methinks you might have trouble producing results in your field. You should probably stick to numerical modeling or theoretical exercises if you continue this kind of attitude towards experiments and "control groups".

Re:Cloud Seeding (1)

bunratty (545641) | more than 4 years ago | (#32585374)

If I were going to test a fishing lure, say a worm, I would test it against some other lure, say a small fish. If I caught twice as many trout with the worm than with the small fish, could I not say that the worm is the more effective lure?

If I picked 200 clouds to fly through, and randomly sprinkled iodide crystals in 100 of them and randomly sprinkled salt crystals in the other 100, and the ones sprinkled with iodide crystals produced twice as much rain, could I not say that the iodide crystals are effective at seeding clouds? Why is it that you say it's "impossible to pick a control group"? It's just using a random generator!

It's not a matter of whether I think I'm smart. Understanding how to create controlled experiments is just not that hard.

Re:Cloud Seeding (2, Insightful)

Billly Gates (198444) | more than 4 years ago | (#32585056)

Unfortunately there is no proof that an external event or condition created the statistical and mathematical variations in the results of the experiment. The conditions can be different clouds, temperature, humidity, and other atmospheric conditions. Academically the clouds and atmospheric conditions have to be and I emphasize have to be identical in the control group to be considered valid. There is no way around it. You can run an expensive experiment yourself but the experts will reject it because there is no proof that the planes, heat, change in pressure, wind, or iodine caused the precipitation. It could be anything?

Running a plane is expensive and since it can not be proved then no one will want to fund it.

Re:Cloud Seeding (3, Insightful)

chaboud (231590) | more than 4 years ago | (#32585326)

You need to read up on the scientific method (and wikipedia is fine: here [wikipedia.org] ). Control groups, as indicated by their name, are statistical instruments that are, by definition, not identical. They can be practically identical, for the purposes of the experiment.

If we were to take your apparent view of science, nothing in the history of scientific inquiry would have been sufficiently proven, as it is highly unlikely that quantum spin characteristics met the burden of having to be identical in the controls of chemical experiments, or that Galileo's balls met the burden of having to be identical except for their mass.

Read up on controls here [wikipedia.org] ...

Statistical controls via randomization are an accepted (and fundamentally sound) approach to the reduction of experimental measurement error. Something being very complex doesn't make it unobservably complex. The assertion is so absurd that it is either a troll or a genuine failure to understand the scalability of reason, causality, and the scientific method.

Re:Cloud Seeding (1)

chaboud (231590) | more than 4 years ago | (#32585080)

Despite the largely chaotic nature of cloud formations (and, thus, the difficulty in modelling behavior), we know that certain inputs, situations, and characteristics have a higher likelihood to lead to expected behaviors than others. It's how we can have hurricane season, make reasonable predictions about precipitation much of the time, etc.

Additionally, weather prediction a week out is a significantly different problem (having to do with predicting the global weather system instead of a comparatively local one) than rainfall prediction tomorrow.

Statistically, of course it is possible to conduct an experiment with a control group (or groups) and draw statistical inferences about the effects of different approaches to cloud-seeding.

We draw localized inferences from economic datasets of enormous magnitude, with many unrecorded inputs. To suggest that we can't draw reasonable inferences through large-scale statistical studies of cloud-seeding suggests a superstition about complexity and chaos indicative of your needing to finish more than just your meteorology classes before you make decrees about what we, as scientists can't do.

Suggesting that "there is no possible way to do any sort" of anything is typically a mistake. If you start a sentence like that, you should end it early.

Re:Cloud Seeding (1)

sexconker (1179573) | more than 4 years ago | (#32585178)

Sorry, but you don't know what you're talking about. There is no possible way to do any sort of control on clouds. They are all different. Trust me - I'm slogging my way through meteorology classes at the moment. I took a class that touched on cloud physics last fall.

Clouds are substantially different, and waaaaay more complicated than human physiology. We're not at the stage that we can measure the amount of water and particle sizes in clouds yet. The best we can do is fly a 3cm diameter probe through a cloud, and sample something like a millionth of it.

You simply need to randomly assign members of the sample size to the test and control group and then compare the results. Repeat until you have a large enough sample size to draw conclusions or design better experiments.

And humans are a tad bit more complex than clouds, I think.

You are an idiot. It comes as no surprise that someone with so little knowledge of the scientific method and/or statistics is well on his way to becoming a "climate scientist".

Re:Cloud Seeding (0)

Anonymous Coward | more than 4 years ago | (#32585292)

You are an idiot. It comes as no surprise that someone with so little knowledge of the scientific method and/or statistics is well on his way to becoming a "climate scientist".

I think this is unfair. This guy definitely needs some training with statistics and experimental design / scientific method, but to propose that he is representative of "climate scientists" is a result of your own misunderstandings in the field of climatology. Unless you think Al Gore is a "climate scientist", in which case it is a result of your misunderstandings in the field of knowing what a scientist is.

Re:Cloud Seeding (1)

harlows_monkeys (106428) | more than 4 years ago | (#32585450)

Sorry, but you don't know what you're talking about. There is no possible way to do any sort of control on clouds. They are all different. Trust me - I'm slogging my way through meteorology classes at the moment. I took a class that touched on cloud physics last fall

Pick 1000 clouds. Randomly assign them to two groups. Try cloud seeding in one of the groups. Fly identical airplanes through the other, going through the motions of cloud seeding, but not actually seeding. Observe results. Apply standard statistical tests of significance to see if there was a meaningful difference in rainfall from the two groups of clouds.

Why would you think the complexity of clouds precludes doing a controlled experiment?

Re:Cloud Seeding (2, Insightful)

Motard (1553251) | more than 4 years ago | (#32584232)

Didn't we have this sort of thing after 9/11? I seem to recall a /. submission about observed weather changes while all the aircraft were grounded.

Re:Cloud Seeding (0)

Anonymous Coward | more than 4 years ago | (#32584562)

Should you not then simply consider the groups to be of planes rather than clouds? If you fly 200 planes through 200 clouds, 100 of which try to actively seed the cloud somehow and the other 100 just fly through without doing anything special, you should be able to tell if there's a difference.

Then again, IANAM.

Re:Cloud Seeding (1)

bunratty (545641) | more than 4 years ago | (#32584692)

That's exactly the way it seems to me, too. Of course, it could be that clouds have a high degree of natural variability, and the effect of cloud seeding may be small, so it could take a very large number of experiments to demonstrate a statistically significant effect for cloud seeding. But that's a different statement altogether from saying that it's impossible to get a control group with clouds, which seems preposterous to me. You get control groups [wikipedia.org] with random assignment, as you explain.

Re:Cloud Seeding (1)

commodore64_love (1445365) | more than 4 years ago | (#32584630)

So conspiracy nut Alex Jones was right after all. The high-flying planes are changing our weather.

Re:Cloud Seeding (3, Interesting)

sexconker (1179573) | more than 4 years ago | (#32585146)

I would think anyone who understands how to design experiments would see the need for a proper control group.

We've already seen that no one who understands how to design experiments has anything to do with the study of weather or climate.

Re:Cloud Seeding (2, Interesting)

Kral_Blbec (1201285) | more than 4 years ago | (#32583580)

Its a matter of distribution and degree. Just a plane might be enough to start off what was almost rain in a area near its flight path, but theoreticly silver seeding would generate rain where it was unlikely and over a wider area that just directly below.

cue the contrails conspiracy (1)

ducomputergeek (595742) | more than 4 years ago | (#32583542)

in 3.....2......1

Chemtrails? (2, Funny)

courteaudotbiz (1191083) | more than 4 years ago | (#32583546)

How long before a conspirationnist comes up with a chemtrail [wikipedia.org] comment?

Re:Chemtrails? (2, Insightful)

JWSmythe (446288) | more than 4 years ago | (#32583666)

    Come on, those guys are entertaining. :) I love the pictures where they show intersecting lines and say that the planes have been flying patterns to drop evil chemicals on the population. Well, the evil chemicals are present, but that's the aircraft's exhaust.

    And for those who don't know, the "grids" are usually created by flights departing in two different directions. They get a pretty regular grid pattern because at busy airports, flights leave at a fairly regular interval. If you read up on how aircraft work, you'll see that the FAA requires a period between large aircraft due to the disturbed air. Failing to do so, the disturbed air would likely do "bad things" (i.e., unintended intersection of the flight path and the ground, in most ungraceful ways).

    Err, I mean every aircraft is fitted with mind altering drugs that is distributed over the city, so some secret government agency can observe how the population reacts. Myself, it makes me laugh at conspiracy nuts who don't really know what they're talking about. I guess the mind control is working. :)

Re:Chemtrails? (1)

bunratty (545641) | more than 4 years ago | (#32583758)

So, you admit the planes are disturbing the air and doing bad things. That is disturbing, indeed!

Re:Chemtrails? (1)

nextekcarl (1402899) | more than 4 years ago | (#32584032)

He is obviously a plant by the Warren commission to distribute falsehoods among the masses. But what even he doesn't know is who is actually behind the commission. My research shows the Girls Scouts of America are in league with the Greys on that one.

Re:Chemtrails? (1)

JWSmythe (446288) | more than 4 years ago | (#32584090)

Well, the bad things [wikipedia.org] would be something like if a Cessna tried to take off immediately behind a heavy jet, the Cessna may find himself tumbling down the runway in most ungraceful ways. It's not limited to small vs big aircraft though. A heavy aircraft following another can have unintended (and nasty) results.

Re:Chemtrails? (1)

bunratty (545641) | more than 4 years ago | (#32584474)

Then it could cause a plane to crash, just like terrorists cause planes to crash? I see.

Re:Chemtrails? (1)

JWSmythe (446288) | more than 4 years ago | (#32584740)

Oh, I see your point now. It's a tool used by terrorists. Anyone causing wake turbulence would therefore be a terrorist. Just like all those evil people caught possessing DHMO [dhmo.org] .

Re:Chemtrails? (1)

bunratty (545641) | more than 4 years ago | (#32584844)

It's a fact that nearly all felons consumed significant quantities of DHMO in the hours before committing their crimes. And nearly all heroin users smoked marijuana before turning to harder drugs.

Re:Chemtrails? (1)

zippthorne (748122) | more than 4 years ago | (#32584850)

Meh oversight on DHMO is too stifling. People in industry tend to use a lot more of the relatively unregulated hydric acid, instead. It's a very good solvent: it dissolves almost everything.

Re:Chemtrails? (2, Informative)

Falconhell (1289630) | more than 4 years ago | (#32584288)

A good photo of what an aircraft does do to the air see;

http://www.skysoaring.com/albums/gliderhumor/Box_This_Wake.jpg [skysoaring.com]

Re:Chemtrails? (1)

JWSmythe (446288) | more than 4 years ago | (#32584676)

    WOW! That's an amazing shot. All the shots I'd seen before were near the ground, to show how the wake turbulence is at ground level, like this one [wikipedia.org] .

Re:Chemtrails? (2, Interesting)

PhreakOfTime (588141) | more than 4 years ago | (#32584618)

I got sucked into a similar discussion once. I will never make that mistake again.

After doing some back of the envelope calculations, using the average size of cloud droplets, the velocity those droplets fall, and the average height those clouds are... I pointed out that the clouds seen over your head would take up to 10 hours(or substantially longer) to fall to ground, and even with a small breeze, would end up hundreds of miles away from the location seen by the time they would reach the ground.

Even faced with that simple math, they would STILL insist that they could see the 'residue' falling into their yard from the airplanes above....

Re:Chemtrails? (1)

petermgreen (876956) | more than 4 years ago | (#32584748)

unintended intersection of the flight path and the ground, in most ungraceful ways
LOL

Kinda similar to a story I heard from my phd supervisor (dunno if it's true or not and my memory of the exact term may be hazy) that someone told him not to use the "M word" and instead to call the things they were talking about single use unmanned air vehicles (i'll leave the reader to figure out what the "M word" was).

Re:Chemtrails? (1)

nido (102070) | more than 4 years ago | (#32585310)

I live in Phoenix and I pay attention to the skies. Haven't seen a chemtrail in a couple months. Maybe it's the summer heat (moved here in November, have seen the chemtrails elsewhere in Arizona before), maybe they stopped spraying when BP's oil volcano went off in the gulf. I don't keep logs or take pictures, so this is just from memory.

With that said, there are still planes flying in and out of Phoenix Sky Harbor International. I'm in one of the flightpaths, so I see those planes all the time. The planes that are approaching and leaving Sky Harbor never leave chemtrails. Perhaps the chemtail planes are drones...

Myself, it makes me laugh at conspiracy nuts who don't really know what they're talking about.

Maybe you live where it's cloudy most the time. If you've never seen an actual chemtrail, it's understandable to assume that they don't really exist. Arizona Skywatch [mydomainwebhost.com] has some pictures. But the site is not worthy of your visit - just something else for you to scoff at.

I guess the mind control is working. :)

We agree here. :)

Re:Chemtrails? (4, Funny)

clarkkent09 (1104833) | more than 4 years ago | (#32584512)

Never heard of chemtrails before but I did notice that my cat is shedding more fur in the summer than in the winter, and there are also more flights from the local airport in the summer. If they can cause cats to shed, imagine what they are doing to your brain! Thanks for opening my eyes.

Re:Chemtrails? (0)

Anonymous Coward | more than 4 years ago | (#32585168)

right now. I don't like the way it's all going but on the + I'm partially exceited by all u little rat wieners who're gonna get a shock

when the wolves are at your door and you've no powere for your iphone nano. You'll have to worry about things like fresh water, and self defense.
Bye wieners!

Surprised? (4, Insightful)

confused one (671304) | more than 4 years ago | (#32583554)

So, we're surprised when a large metal object that sucks in cold air and spits out water vapor (and CO2) by the ton, affects cloud formation?

More of a duh, really. (5, Funny)

vandoravp (709954) | more than 4 years ago | (#32583574)

They are just giant butterflies, after all.

Re:Surprised? (1)

apoc.famine (621563) | more than 4 years ago | (#32584304)

Not many people studying clouds are surprised. It's pretty well established that any sort of disturbance can affect cloud formation. There have been discussions for years that "cloud seeding" may just be caused by the plane flying through the clouds.

Not surprising (4, Interesting)

JWSmythe (446288) | more than 4 years ago | (#32583566)

    This isn't terribly surprising. Clouds are a delicate formation of moisture that hasn't collected into dense enough masses to fall. Aircraft disturb the air, blowing that moisture around. We've known about contrails for an awful long time. I wouldn't be terribly surprised to find that particles in the exhaust give the moisture something to cling to (i.e., cloud seeding).

    Those are some nice pictures though.

Re:Not surprising (0)

Anonymous Coward | more than 4 years ago | (#32583656)

As the Air is accelerated over the wing it condenses the moisture within it, thus precipitating percipitation. If the conditions are right - it canresult in a chain reaction of sorts. The mystery is why anyone thinks this is a mystery! Any pilot who has flown through clouds can tell you this.

Re:Not surprising (1)

JWSmythe (446288) | more than 4 years ago | (#32584128)

    You don't have to be a pilot to observe it. I've seen some very nice examples of contrails, while riding in commercial aircraft. I like to sit behind the wing, so I can observe what the pilot is doing. It's not like I can do anything about it, but at least it's better than sitting back completely oblivious to what's happening. A few drinks later, it doesn't really matter though, I'll take a nice nap until I hear the landing gear go down. :)

Re:Not surprising (2, Funny)

zippthorne (748122) | more than 4 years ago | (#32584880)

    A few drinks later, it doesn't really matter though, I'll take a nice nap until I hear the landing gear go down. :)

Based on what I've seen of pilots, they're thinking the same thing....

Re:Not surprising (0)

Anonymous Coward | more than 4 years ago | (#32584050)

I've previously read a write-up on persistent cloud formations over shipping lanes and harbors so the exhaust itself is likely a factor.

Can't find anything in depth at the moment, but there is mention of it here [pbs.org]

Re:Not surprising (1)

JWSmythe (446288) | more than 4 years ago | (#32584174)

    Hmmm, that's interesting. I hadn't seen anything about it before, but I found several references [google.com] for more information. Thanks, now I have some reading for today. :)

Re:Not surprising (1)

JWSmythe (446288) | more than 4 years ago | (#32584248)

Here's a [nasa.gov] couple writeups [nasa.gov] from NASA on the phenomenon, with some interesting pictures.

    Of course, since it's from the government, conspiracy nuts will say it's disinformation. :)

 

I thought this was well established? (4, Interesting)

Deagol (323173) | more than 4 years ago | (#32583584)

The data from the near-universal grounding of US airspace the days following the 9/11/01 attacks shows pretty conclusively that air traffic has a non-trivial affect on weather patterns. Or at least that's what's I recall from the time.

Re:I thought this was well established? (1)

Dragoniz3r (992309) | more than 4 years ago | (#32583824)

One instance != "well established"

Re:I thought this was well established? (3, Insightful)

cowscows (103644) | more than 4 years ago | (#32584246)

That's not always true. While one instance certainly isn't enough data to completely explore and explain a phenomena, it can certainly establish that said phenomena exists.

And it's not like we're talking about a data-set of one plane canceling a flight. We're talking about a couple of days, and tens of thousands of flights, all across a big stretch of the planet. That's more than just an anecdote.

Re:I thought this was well established? (0)

Anonymous Coward | more than 4 years ago | (#32584348)

Happened again with the Icelandic volcano. Thats two data points.

Re:I thought this was well established? (1)

LoudMusic (199347) | more than 4 years ago | (#32584558)

Certainly. But that second data point is clouded with mud and ash.

Re:I thought this was well established? (1)

lawpoop (604919) | more than 4 years ago | (#32584650)

PBS had a great show called Dimming the Sun [pbs.org] and IIRC they delve into showing how the 9/11 air traffic halt raised the temperature in American cities by 1 or 2 degrees. The contrail cover from planes reflect more light from the sun.

Forcing (2, Interesting)

ShakaUVM (157947) | more than 4 years ago | (#32584908)

>>The contrail cover from planes reflect more light from the sun.

Also, it's important to state that up until this point, climatologists thought that contrails had a forcing effect helping to cause global warming. And still show it that way, for example: http://en.wikipedia.org/wiki/Radiative_forcing [wikipedia.org]

However, papers like this: http://www.nature.com/nature/journal/v418/n6898/full/418601a.html [nature.com] rather convincingly argued that they have a rather strong forcing in the opposite direction (i.e. that they help to dim sunlight more than they trap heat).

While honest climatologists will admit that some areas in AGW are very well understood, and others are much less understood, dishonest climatologists will pretend that they know everything and how dare you for questioning the global warming groupthink. In fact, how they respond to reasoned criticism is often a clear giveaway as to which camp they fall into.

Re:Forcing (3, Informative)

Abcd1234 (188840) | more than 4 years ago | (#32585090)

Yeah, pity you're actually reading the fucking results wrong. *sigh* To quote wikipedia [wikipedia.org] :

Measurements showed that without contrails, the local diurnal temperature range (difference of day and night temperatures) was about 1 degree Celsius higher than immediately before

The daytime temperature didn't increase. The difference between night and day increased. And guess what? That matches expectations! Why? Because:

Other studies have determined that night flights are mostly responsible for the warming effect

So when there are contrails, it stays warmer at night, due to radiative forcing effects. No contrails? It gets colder at night. End result? *Larger night-day temperature difference*.

But, hey, let's actually look at your study, shall we? Hey, here's a choice quote from the abstract:

Because persisting contrails can reduce the transfer of both incoming solar and outgoing infrared radiation4, 5 and so reduce the daily temperature range, we attribute at least a portion of this anomaly to the absence of contrails over this period.

Hey, look at that... that's what they fucking found. Science at work: scientists make prediction. Scientists have convenient experiment. Observations match predictions. The system works.

But, hey, don't let facts get in the way of your "skepticism".

Re:I thought this was well established? (1)

Abcd1234 (188840) | more than 4 years ago | (#32585114)

PBS had a great show called Dimming the Sun and IIRC they delve into showing how the 9/11 air traffic halt raised the temperature in American cities by 1 or 2 degrees.

Err, no, that's not right.

What they found was that the night-day temperature difference increased by about a degree, which makes sense if contrails are insulating the atmosphere (due to less heat escaping at night).

mod parent up (1)

bussdriver (620565) | more than 4 years ago | (#32585316)

if I just had some mod points

War Unexpectedly (-1)

Anonymous Coward | more than 4 years ago | (#32583586)

makes warmongers (a.k.a. industrial-military-pharmaceutical complex) rich [firedoglake.com]

Yours In Osh,
Kilgore Trout

Tenerife (5, Interesting)

bigtomrodney (993427) | more than 4 years ago | (#32583616)

It is well known locally on the Canary Islands that this happens. Almost all flights come in on Tuesdays and Saturdays if I remember correctly - they're almost all package deals and charters. By the afternoon on those two days the temperature drops several degrees celsius and you'll see clouds. I even saw a dribble of rain once.

I was a complete skeptic when I was told this as I arrived, but like clockwork on those days I always saw the same thing. The crazy thing is that any other day of the week around the summer you can expect mid-to-high thirties and rarely a cloud in the sky. So maybe not scientific, but anecdotal evidence anyway.

Re:Tenerife (1)

bazorg (911295) | more than 4 years ago | (#32583752)

any change when the whole european airspace was closed a while ago?

Re:Tenerife (5, Funny)

Anonymous Coward | more than 4 years ago | (#32583836)

You mean when it was closed because of a volcanic ash cloud? I'm sure we can attribute any and all weather changes entirely to the lack of airplanes...

Re:Tenerife (1)

bigtomrodney (993427) | more than 4 years ago | (#32584768)

It's funny you ask that, we had a few days of sunshine here in Dublin when our airspace was closed and that was the first thing that was suggested. I mean, it's Ireland...sunshine is on backorder here.

Unintended Consequences (0)

Anonymous Coward | more than 4 years ago | (#32583622)

Sure they weren't just emptying the onboard toilets?

Re:Unintended Consequences (2, Insightful)

AnonymousClown (1788472) | more than 4 years ago | (#32583718)

Sure they weren't just emptying the onboard toilets?

Then there would have been blue clouds and blue snow.

Anyway, Pilots couldn't even if they wanted to. [wikipedia.org]

lolwut? (0)

Loopy (41728) | more than 4 years ago | (#32583744)

Changing the airflow and/or temperature in parts of cloud formations causes changes in the precipitation of said clouds? Say it ain't so!

Military Applications (0)

somaTh (1154199) | more than 4 years ago | (#32583754)

Am I the only one that considered flying in mass numbers over areas that have the right conditions to flash flood it? Or in the path between a country's fields and their normal cloud movements to cause a drought? Maybe I'm assuming precision that isn't there.

I guess it could be used to bring rain to fields. That could be good, too.

Re: Military Applications (1)

Black Parrot (19622) | more than 4 years ago | (#32583954)

Am I the only one that considered flying in mass numbers over areas that have the right conditions to flash flood it?

Only as in "dambusters".

Potential AGW support? (5, Interesting)

OzPeter (195038) | more than 4 years ago | (#32583852)

I'm not deep into the AGW/anti-AGW arguments (and not trying to start a flame war), but I thought that one of the anti-AGW arguments was that in general humans can't affect climate. This sort of research would seem to suggest that humans can affect climate and hence nullify some of the anti-AGW stance - or are these effects so localized that you can only state that the humans are affecting weather and not climate?

Re:Potential AGW support? (1, Insightful)

Anonymous Coward | more than 4 years ago | (#32583892)

According to the article the effects are very localized, so it's only weather, not climate.

Re:Potential AGW support? (2, Insightful)

Anonymous Coward | more than 4 years ago | (#32583996)

Unless hundreds of thousands of aircraft are going around causing these "localized effects", 24 hours a day, seven days a week. (Hint: that's the scope of the air transit industry)

Re:Potential AGW support? (0)

Anonymous Coward | more than 4 years ago | (#32583998)

Change enough of the weather, you're going to change the climate.

It's like the Dust Bowl. They didn't just ruin one farm.

Re:Potential AGW support? (1)

Charliemopps (1157495) | more than 4 years ago | (#32584430)

Affecting the local climate is one thing, affecting it globally is entirely different.

Re:Potential AGW support? (1)

lawpoop (604919) | more than 4 years ago | (#32584688)

I thought that one of the anti-AGW arguments was that in general humans can't affect climate

. If a person believes this from the outset, they have an ideology ( "Man can never fly as birds can" "No thing can travel faster than the speed of sound" "Man can never affect the climate" ), and probably no amount of evidence will dislodge them from their position.

If they believe that humans haven't affected climate, then there's hope :)

Re:Potential AGW support? (0)

Anonymous Coward | more than 4 years ago | (#32584736)

I was expecting some trolling saying the opposite, actually, say some tosh along the lines of "see, there's the *real* cause of global warming. Greenhouse gases hah, it's all just planes: now excuse me while I stick my head back in the sand".

Re:Potential AGW support? (1)

Graff (532189) | more than 4 years ago | (#32584992)

I'm not deep into the AGW/anti-AGW arguments (and not trying to start a flame war), but I thought that one of the anti-AGW arguments was that in general humans can't affect climate.

First off, there are morons on both sides. Some people loudly exclaim that humans have ruined everything and some roar that humans have no effect on their environment. Both points of view are ridiculous.

The more reasonable proponents of climate change assert that mankind has had a measurable, long-term effect on the environment that will be difficult to reverse and requires drastic and immediate measures to prevent a catastrophe. Opponents of this point of view argue that the environment has gone through many similar changes in the past and that there is no clear evidence that mankind is the cause of current short-term trends that have been observed.

Of course mankind can affect climate on a local, short-term scale, that's been established and shown many times. The question is whether or not there are any large-scale, long-term, potentially difficult to reverse or control changes. It's a tough question to answer because we really don't have a great understanding of this extremely complex system known as Earth. The fact that aircraft can effect cloud formations has been known for some time and new data is a good thing but it doesn't really give either side much real evidence either way.

Hello Capt. Obvious (2, Insightful)

DaMattster (977781) | more than 4 years ago | (#32584004)

I wish I could tag this one as duh. Weather is bound to be generated when you pass a hot jet engine through a cold cloud. Not to mention the heat of the fuselage generate from air friction. Although, I was impressed that several inches of snow has the potential to form.

Attention! Warp Restrictions Are Now In Effect (0)

Anonymous Coward | more than 4 years ago | (#32584178)

Oh...wait... wrong millennium.

the short D20 version of this (its a dice roll) (3, Funny)

RobertLTux (260313) | more than 4 years ago | (#32584220)

to create a rain/snow storm in a given area certain things have to happen

lets say you need to roll 60 on a d100 to get rain and roll a 4 (on a d6) to get snow IF YOU ROLL RAIN

just dartboarding a few factors you need to have
greater than X% humidity (add 7 to your roll for every 10% above X)
a cold front near by to generate the clouds (and provide for some winds) (add 2 for every 1.5 degree difference)
enough seeds in the clouds to tilt things past the equalibrium
a low enough temp that the water doesn't boil off (penalty of 1 on the d6 roll for every 20 degrees above 0C)

now having a bunch of planes i would bet could 1 add to the "muck" in the air 2 twist the temps a bit 3 do a whole lot more than a butterfly in generating wind

We already knew this from ST:TNG. (0)

Anonymous Coward | more than 4 years ago | (#32584404)

Didn't these scientists watch where Picard learns that warp drive destroys the time space fabric?

I don't understand the Karma System (1)

mlawrence (1094477) | more than 4 years ago | (#32584684)

I had neutral Karma, then I made the first post here (currently at +4 Funny) and now I am bad karma. Don't know where else to post this question. :) Martin

Re:I don't understand the Karma System (4, Funny)

Anachragnome (1008495) | more than 4 years ago | (#32585256)

The Slashdot moderation systems is a system of layers.

Users are randomly assigned "moderation points" that can be spent moderating a post upwards "+1", or down with "-1" and include a "tag".

Once spent, the points are painted onto ping pong balls--"+" balls and "-" balls. These are then thrown together in a large hopper and fed down a tube to the squirrel cage. In this cage, dozens of specially trained squirrels sort the ping pong balls according to size and shape and drop them down appropriate tubes to be further sorted by the next stage of squirrels. Once fully sorted, each ping pong ball is individually routed through a pipe that determines the tag that will be applied. The ping pong balls are then routed back to the beginning of the system. The ping pong balls are siphoned off from various points throughout the system at the same rate that posts are made. Each ping pong ball is then assigned to a random post, and there ya have it--Slashdot moderation.

I hope that helps.

Cooling? (2, Insightful)

pookemon (909195) | more than 4 years ago | (#32584894)

I find it a little odd that TFA talks about how an aircraft flying through a cloud causes it to "cool", resulting in the supercooled liquid suddenly freezing. There's a very well known phenomenon with supercooled water where it will remain in a liquid form, until it comes into contact with ice crystals. I would think that that was a far more likely cause of the clouds suddenly being filled with ice rather than a jet or turboprop "cooling" an already supercooled cloud.

My 2c

Opposite effect (2, Interesting)

GaryOlson (737642) | more than 4 years ago | (#32585084)

Anyone who has watched weather fronts as they approach DFW airport can provide anecdotal data showing the reverse effect -- aircraft disperse clouds. Huge storm fronts slam into Fort Worth, the middle dissipates as it approaches and passes over DFW airport, then storm fronts reconnect east to reform a single storm front. How far east depends on the strength of the storm. Or the splitting of the front at DFW airport will cause the storm front to degrade to localized cells. Very few storm fronts survive the impact of DFW airport as a continuous front. YMMV....

Re:Opposite effect (0)

Anonymous Coward | more than 4 years ago | (#32585234)

Giant stretch of tarmac or planes, which would cause a high pressure zone.

Hmm...

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?