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."
Was this plane belonged to the Mexican Cocaine Cartels, who thought they were being trailed.
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?
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.
Serious? Seriousness is well above my pay grade.
They are just giant butterflies, after all.
That was suggested back in 1970--- that cloud seeding experiments need to consider the possibility that the plane's flight itself is doing the seeding.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
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.
Method of processing duck feet
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.
I never get used to these constant resurrections
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?
I am Slashdot. Are you Slashdot as well?
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.
Negative moral value of force outweighs the positive value of good intentions.
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.
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.
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.
Your post is littered with falsehoods. I barely know where to start. Whether you realize it or not, you're concern trolling from ignorance.
We still do not have enough evidence to prove that burning fossil fuels will produce global warming.
Eh? What?`
First off, basic physics predicts that more CO2 and methane (and other greenhouse gasses) in the air will cause the atmosphere, and hence, the ground, to heat up. In a glass jar, CO2 behaves precisely as expected.
The Earth is more complex than a glass jar, it's true, but to argue against global CO2-based warming, you need a plausible physical explanation for where the heat caused by the CO2 went. Unless some obscuring agent prevents sunlight from hitting the CO2, the heat from was undoubtedly generated in the atmosphere nearly exactly as predicted by physics. So where does it go?
In addition to a magic (heretofore invisible) heat-sink, you need a plausible alternative explanation for the geologic record, dating back 100s of thousands of years, showing that, indeed, CO2 and warming are in a feedback-loop, punctuated by various global disasters.
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.
This is a ridiculous cop-out, and is a lousy argument for destroying civilization as we know it.
The fact is, we've had a pretty nice equilibrium here for thousands of years. Throwing off that balance could mean a lot of different possible things, but it definitely means chaos and turmoil.
We don't know everything, but we know some things. We know that the gulf-stream is very important to heating up North America. We know that North America would turn in to a block of ice if it were to shut down. We may not know how to keep it running, but that's not a good reason to toss a bunch of carbon in the air to see what happens.
The best plan is probably to try to maintain the equilibrium somehow. It's worked for a while. I like the coasts where they are, and I don't want to experiment with their shape, thank you very much. If I were in a rowboat with you, I also wouldn't want you to experiment by standing up and rocking it back and forth.
I'll deal with two more of your arguments.
Global temperatures have been on the decline for the last decade, much as they did during the turn of the century 100 years ago.
Incorrect. 1999-2009 were the hottest decade in human history. 2009 was about as hot as the previously hottest year on record, 2005, and possibly hotter, depending on what source you use. This can hardly be described as a decline, and is a typical misconception sponsored by various media outlets.
2010 is trading on Intrade at 67% to be the warmest year on record. You could make a pretty nice sum by betting against it, getting back two times your money at that price level.
Only if you cherry pick 1998-2007 from the data can you claim a "decline", which really isn't a decline, it's a squiggle that bounces back and forth, ending up just below the top.
You may not be a denier, but you sure play one on /.
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.
Possibly because you made up that as a requirement. Your argument is irrelevant and spurious. Physics predicts a warming as CO2 rises. CO2 levels are rising dramatically, as we have observed. The temperature is rising dramatically, as we have observed, your weak protestations to the contrary notwithstanding.
Yes, the oceans absorb some. This isn't a question as you intimate, it has been measured. The question of whether increased CO2 in the atmosp
To quote wikipedia:
is inherently invalid.
This sig left unintentionally blank.