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."

Comments

Surprised?

[confused one]

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?

Re:Cloud Seeding

[Smauler]

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:I thought this was well established?

[cowscows]

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:Cloud Seeding

[chaboud]

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.

Re:Opposite effect

[forceman130]

I'm guessing that has more to do with the heat coming off all that tarmac than it does with the aircraft themselves.

Re:Potential AGW support?

[gillbates]

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:

1. The first is political: the fallout from the IPCC scandal is going to take years before the public will believe them again. But it hardly matters because,
2. Global temperatures have been on the decline for the last decade, much as they did during the turn of the century 100 years ago.
3. We can probably agree that CO2 is a greenhouse gas; what we can't explain is why increased generation of CO2 hasn't resulted in a proportionate increase in the atmospheric CO2 levels. Some say it is being absorbed by the oceans (possibly correct) and will acidify them. (Also possibly true, however, a great deal of CO2 will be necessary to sufficiently alter the pH enough to matter.)

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.

Re:Cloud Seeding

[The_Wilschon]

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.

Re:Chemtrails?

[JWSmythe]

    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.