Slashdot Mirror
Airplanes Unexpectedly Modify Weather
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."
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?
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. :)
Serious? Seriousness is well above my pay grade.
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.
RIP America
July 4, 1776 - September 11, 2001
According to the article the effects are very localized, so it's only weather, not climate.
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.
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)
You sound new to /.
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.
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.
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.
One time I threw a brick at a duck.
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.
What a fool believes, he sees, no wise man has the power to reason away.
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
dnuof eruc rof aixelsid
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.
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.
http://saveie6.com/
You need to read up on the scientific method (and wikipedia is fine: here). 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...
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.
I'm guessing that has more to do with the heat coming off all that tarmac than it does with the aircraft themselves.
Wow, a 7 digit ID - let that be a lesson in the perils of procrastination.
We've known for a long time that humans can affect not only weather, but climate. Since the 60's, we've known that clouds seeded with silver nitrate will produce precipitation. IIRC, the same was demonstrated with chips of solid carbon dioxide. However, that said -
We still do not have enough evidence to prove that burning fossil fuels will produce global warming. Now before I continue, let me just get this out of the way: there is a difference between someone who believes global warming *can't* be true in the religious sense, and someone who recognizes that climate is a difficult subject for which we just don't have the answers now. There will always be anti-AGW folks around regardless of where the science goes and what happens to the climate. That said, the AGW theories have these difficulties:
At this point, we simply don't have the scientific certainty to claim AGW is happening, and that it will be catastrophic. Even were we to accept the AGW theories at face value, they are so filled with qualifying factors that we could not conclude that we are in imminent danger. We could say that change is going to come, but we can't quantify the impact. Given the timescales on which climate changes, it would hardly be an unmitigated disaster on a global level. Even if the direst of predictions proved true, we'd have more than ample time to adapt. (Keep in mind the US sustained not one, but two wars in the Middle East, at the cost of trillions of dollars. Imagine what the same could do to relocate US cities inland, if necessary.)
The simple fact of the matter is, though, that we're well past peak oil, and AGW or not, we're going to stop burning it someday. So it only makes sense to buy into renewable energy technologies while they're cheap than wait for the oil to run out and be put over a barrel (no pun intended) by the solar power companies. If you want people to stop burning fossil fuels, you just have to give them a cheaper alternative. You don't have to lie to them about global warming.
The society for a thought-free internet welcomes you.
It seems to me that the issue lies in the extremely broad cloud classifications--this comes not from any training but from reading apoc.famine's posts. If you visualize words like 'cirrus,' 'nimbus,' and 'stratus' to be categories for clouds similar to the rock categories 'igneous,' 'metamorphic,' and 'sedimentary,' and then think of the extremely varied characteristics of rocks within each category, and finally imagine that instead of flying a plane through cloud we are hitting rocks with a hammer and chisel to see how they split, you can grasp the potential for so many unknowns as to make the experiment worthless.
I don't know how well metaphor holds, as I said this is just inference, but I don't think it an absurd possibility that we know less about cloud behavior than the layman would believe.
Your brain is not a computer.
A lot of that has to do with the specific weather conditions where that contrail was. Sometimes it'll disperse quickly. Sometimes it'll take some time. Humidity, wind, temperature, pressure, aircraft configuration and load all change the way it works. You can have significant differences in a relatively small area.
I seriously doubt any commercial carrier has equipped their aircraft with any super secret government gassing project. :) How exactly do you explain to the ground crew, "ok, fuel it up here, and then fill with this hose marked classified US Gov't property here." Someone besides the conspiracy nuts is going to talk.
Serious? Seriousness is well above my pay grade.
I'm very glad that you've taken classes, and I'm even more glad that you're taking obviously quite a lot of time to think about this. However, as a working scientist (HEP) myself, I have to assert that you are quite wrong. Take a large number of clouds. Fly a plane through each one of them, half of the time dropping cloud seeding crystals, half of the time not (choose by flipping a coin). Fill two histograms with the integrated radar echo strength, beginning from the moment the pilot reports entering the cloud, and ending with the time the cloud ceases to precipitate, or one hour later, or some such. Obviously, put the data from the seeding runs in one histogram, and the data from the non-seeding runs in the other. At this point, you have obtained approximations to two distributions. You can obtain error bars on each bin of each histogram (poisson statistics), and estimate systematic errors on top (in quadrature) of those. Now, you can do a K-S test, or a Chi-squared test, or an eyeball test, and determine whether the two distributions are commensurate within experimental error or not. Quote Bayesian credibility, or confidence levels, or whatnot. Done. You have a successful experiment and a publication.
The key to the experiment is that the set of all clouds has some (currently unknown, but definitely fixed) distribution of rainfall amounts. As you draw samples from this distribution and fill a histogram, you get an idea (perhaps fairly coarse) of what that distribution is. Then you draw samples from a different distribution (seeded clouds), and get an idea of what that distribution is, too. Do these distributions appear to be different, or are they similar enough that we can't tell? Since what matters is the distribution as a whole, we don't need to worry about matched pairs in control and experimental groups, or what the characteristics of individual clouds are. Trust me, we have exactly the same situation in HEP. No two collisions are ever exactly (or really even close to exactly) alike, so if matched pairs were required, we'd never get anywhere at all.
The kicker is, of course, getting enough samples to populate your histograms sufficiently to get a good enough idea of the distributions. You are asserting that there are too many variables in cloud configuration space (and you're right, there certainly are an awful lot). But we don't care about filling up cloud configuration space. What we care about is filling up integrated radar echo (as an approximation to rainfall amount) space, which is one dimensional, and therefore much, much easier to populate.
SIGSEGV caught, terminating
wait... not that kind of sig.
Their implication is that there would be a white plume from the engines. If it were mixed with the jet fuel, it would always be present. Folks would notice if aircraft were putting off that kind of smoke. It may not be totally noticeable when taxiing, but it would be obvious during takeoff.
Being that aircraft all fuel from the same source at the airport, there would be no difference between aircraft, that is usually reported with chemtrails. As I've read it over the years, some dissipate quickly. Some linger for a long time. If it was included as a fuel additive for commercial aircraft, there would be no "sometimes" to it.
And just because a patent was issued doesn't mean that it really works, or that it's in use. People get patents all the time that lay dormant forever.
Serious? Seriousness is well above my pay grade.