posted 03-09-2003 12:14 AM            

Contrail ice crystals evaporate quickly when the ambient air is subsaturated with respect to ice, unless the particles are coated with other species such as HNO3 (Diehl and Mitra, 1998). Simulations suggest that a few monolayers of HNO3 may condense onto ice particle surfaces and form NAT particles in stratospheric contrails (Kärcher, 1996). These particles would be thermodynamically stable and longer lived and would cause a different chemical perturbation than would short-lived stratospheric contrails composed of water ice.

volatile particles may contribute considerably to ice crystal nucleation at temperatures below the contrail threshold value. This result is supported by observations of contrails and their microphysical properties for different fuel sulfur levels (Petzold et al., 1997)

posted 03-09-2003 12:41 AM            

It's ok... you can call me a "debunker" if you want! I've been called worse...

<< Isn't that cute? He just recently heard about chemtrails. >>

Now, I gotta say that I'm not so sure why you find this "cute", but, uh, whatever does it for you, man. If we ever end up on the same plane, train, bus etc. just maintain proper male spacing, ok?

<< I don't know about the rest of you guys, but if I thought for one minute that all these "pilots" on the boards were for real, I would never fly again! >>

Guess I don't really understand this, either. I'm not sure what I said to give you reason to doubt me or my flying abilities, but you're entitled to your opinion. But, why in the world would anyone lie about being an airline pilot? It's not exactly a glamorous profession. It seems to me that if you folks are on this board for the purpose of exchanging all information relating to this topic, we'd be your best friends! No one else has the perspective we have, on the sky or the daily goings-on in the airspace system. I imagine you don't like the pilots here because they probably all disbelieve this chemtrail theory. They probably all disbelieve it for the same reasons I do:
1. It's logistically impossible. You guys theorize that a good portion of the contrails you're seeing are really chemtrails. This suggests that, in addition to ALL the commercial and private aircraft in the flight levels, there's room for a secret fleet of military aircraft to operate, similar in size to the civilian fleet. THERE IS NO WAY. Even with airline schedule cutbacks, the national airspace system is operating near capacity. Why do you think you will sometimes hold for half an hour going into a large airport when the weather is good and there's no apparent reason for a delay? Just too many airplanes. There isn't room for a large spraying fleet. ATC could never handle it; there'd be mid-airs and near-misses left and right.
2. If there was something suspicious going on up there, we'd know about it. We'd see it. That's all we do in cruise, sit there and stare out the window (well, ok, sometimes we read the paper). If there were large numbers of aircraft flying strange patterns and leaving unusual contrails, we'd have front row seats to all of it. We're seeing the same things you all are, of course; it's just that they aren't unusual to us because we understand them. And here's a thought: it is not unusual at all to fly through a contrail, indeed sometimes to stay in one for minutes at a time as you follow same-altitude traffic down an airway. Now, if your thinking is correct and a good portion of these are chemtrails, why am I not dead? Why aren't airplanes plunging regularly to earth because their crews and pax were overcome by some concentrated toxic chemicals? If this stuff is bad enough to make people sick and dead after it drifts down and disburses through thirty thousand feet of atmosphere, why doesn't it kill me instantly when I fly through it and it's force-fed into my AC packs??

Just points to ponder. X, your reply to my post was heavy on condescension and dismissal, and very light (completely devoid) of any facts backing up your position. I asked good questions the first time around, and I've asked more now. Do you have any good answers??

Joe

posted 03-09-2003 01:28 AM            

How is my sudden appearance coincidental? I'm a new forum user, and this happened to be the top discussion, that's all. I certainly wasn't "baiting" anyone into a deflective arguement. I was just offering my theory on why our San Fran resident is seeing fewer contrails now. Sure, some of it is no doubt atmospheric, but a large part of it is simply fewer flights. Hacums razor, ya know: the simplest explanation tends to be the right one. I was then promptly personally attacked and scorned by someone with absolutely no justification, and I responded as anyone would. I don't see that I've really posted anything off-topic, but I will gladly be more careful in the future.

posted 03-09-2003 07:34 AM            

Welcome, BTW,

posted 03-09-2003 08:20 AM            

As you have already noticed, if chemmies are faced with actual problems with their conspiracy theorys, they will resort to personal attacks or completely absurd responses. (eg:Cutlass, I find your sudden appearance on this particular thread, and your proclivity for posting off-topic questions and/or baiting participants into deflective arguements to be highly co-incidental.)

posted 03-09-2003 09:21 PM            

quote:
"Simulations suggest that a few monolayers of HNO3 may condense onto ice particle surfaces and form NAT particles in stratospheric contrails (Kärcher, 1996). These particles would be thermodynamically stable and longer lived and would cause a different chemical perturbation than would short-lived stratospheric contrails composed of water ice."

Chemdude,
Why are you worried about "short-lived contrails in the stratosphere"? I thought we were talking about long-lived contrails in the troposphere. (Contrails don't live very long in the stratosphere. It's too dry.)

quote from Chemii post:
"volatile particles may contribute considerably to ice crystal nucleation at temperatures below the contrail threshold value. This result is supported by observations of contrails and their microphysical properties for different fuel sulfur levels (Petzold et al., 1997)"

Does that have anything to do with persistent contrails?

The next four quotes are from B. Karcher, "Aviation-produced aerosol and contrails," Surveys of Geophysics, 113-167, 1999.

1.
"Contrails consist of ice particles that nucleate primarily on aerosol particles that are emitted or are formed in the plume, as predicted by models (e.g., Karcher et al., 1995, 1996b; Brown et al., 1996a, 1997; Yu and Turco, 1998b; Gleitsmann and Zellner, 1998) and inferred by in situ contrail observations (e.g., Schumann et al., 1996; Petzold et al., 1997; Anderson et al., 1998). Simulations strongly suggest that contrails would also form without soot and sulfur emissions by activation and freezing of background particles (Karcher et al., 1998a)."

2.
"Contrail persistence is linked to synoptic conditions that support vertical motions of air, such as frontal zones connected with the warm sector of lows, jet streams that carry moist air across stable highs, andows induced by mountain waves. These conditions ensure that the relative humidity exceeds ice saturation, promoting depositional growth of the contrail crystals. Recent in situ observations have revealed that often large regions exist in the upper troposphere which are characterized by very large ice relative humidities (up to 160%), but void of ice clouds (Heymsfield et al., 1998)."

3.
"According to these and other measurements (e.g., Anderson et al., 1998a), the formation of contrails is only weakly linked to the sulfur content in the fuel."

4.
"Contrail properties do not strongly depend on the level of sulfur in the plume (Figure 16) because ice formation and growth is a self-limiting process and depletion of H2O from the gas phase prevents further nucleation when the concentration of ice particles exceeds 105 cm"

Canecks quote:
"The only difference was that the concentration of particles was somewhat lower in the low sulfur fuel. I do not have references handy but can dig them up if you are really interested.
The spreading of the contrails has more to do with the depth of the supersaturation layer, the wind shear, and turbulence. A greater number of particles may extend the lifetime of the contrail and perhaps allow it to spread a little more, but the difference so far has not been shown to be great enough to worry about. That does not mean that it won't be in the future. But there are no that many people researching contrails."

posted 03-09-2003 09:56 PM            

These particles would be thermodynamically stable and longer lived and would cause a different chemical perturbation than would short-lived stratospheric contrails composed of water ice."

quote:

---

"volatile particles may contribute considerably to ice crystal nucleation at temperatures below the contrail threshold value. This result is supported by observations of contrails and their microphysical properties for different fuel sulfur levels (Petzold et al., 1997)"

Does that have anything to do with persistent contrails?

---

Canex, I undertand it can be hard for you to keep track of the various discussion elements on a thread this convoluted, but for pity's sake...

It has to do with the formation of trails under conditions where normal contrails would not occur. Contradictions? Abound? Contrail? Forecast? Any of this ring a bell?

I'l skip your selective references routine, and re-post the unsanitzed version that you may have forgotten about by this time, as well...

posted 03-09-2003 10:45 PM            

Your quotes aren't selected? Your Schumann quote does not contradict what I said earlier. The particles and concentrations will be changed. It still is a minor player in persistence and has minmal effect on formation.

Do you know what the chemical perturbation is that Petzold was talking about? Does it make any difference if the contrail does not persist? Are you worried about the chemical perturbation that aircraft exhaust has inthe stratosphere? Contrails do not persist in the stratosphere whether they get a coating or not. It is too dry. Have you seen contrails forming in air in which they should not form?

posted 03-09-2003 11:56 PM            

Do you know what longer lived means? Do you know what considerably means? Let me help you out here, Einstein... it's roughly the antithesis of 'minimal'.

I'm not trying to say anything; I'm saying it... and if you can't keep up with the conversation, perhaps it would be best if you didn't say anything at all.

posted 03-10-2003 09:27 PM            

Your charity is unecessary. Read my statement again:

quote from Canex;
"It has been found in several different experiments that the aerosols formed from the exhaust products play little or no role in contrail formation"

Formation comes first, followed by the contrail properties.

quote from Canex again:
"The only difference was that the concentration of particles was somewhat lower in the low sulfur fuel...
The spreading of the contrails has more to do with the depth of the supersaturation layer, the wind shear, and turbulence. A greater number of particles may extend the lifetime of the contrail and perhaps allow it to spread a little more, but the difference so far has not been shown to be great enough to worry about. That does not mean that it won't be in the future. But there are no that many people researching contrails."

Notice the words “concentration” and “greater number of particles” (that means the particles are smaller for the same amount of water). Now the Schumann quote:
"Contrails at threshold conditions appear to be formed for very low (2 ppm) fuel sulfur content in the same manner as for average fuel sulfur content (260 ppm) (Busen and Schumann, 1995), but their properties differ measurably for larger fuel sulfur content (Schumann et al., 1996)."

See how the words are lined up. First the formation: "formed for very low fuel sulfur content in the same manner for average sulfur content" Same means no difference.

Then they talk about the properties: "properties differ measurably" = concentration of particles and size of particles are different. Where's the contradiction, Curly? If your goal here is to play gotcha, you have to know what you are talking about, know what all of the words mean, or have proof that I was wrong. You’re batting .000.

Next batter.
Your next quote:

"Contrail ice crystals evaporate quickly when the ambient air is subsaturated with respect to ice, unless the particles are coated with other species such as HNO3 (Diehl and Mitra, 1998). Simulations suggest that a few monolayers of HNO3 may condense onto ice particle surfaces and form NAT particles in stratospheric contrails (Kärcher, 1996). These particles would be thermodynamically stable and longer lived and would cause a different chemical perturbation than would short-lived stratospheric contrails composed of water ice."

You left out the key next sentence:
"However, the relevance of this effect on larger scales has not yet been studied because no parameterization of NAT particle nucleation in aircraft plumes exists for use in atmospheric models."

Now, please consider the two quotes above in context. They are discussing contrail formation right behind the aircraft, not contrail persistence. Next consider the words, "unless the particles are coated with other species such as HNO3", The Diehl and Mitra study was performed in a laboratory with a kerosene burner. The coatings on the crystals made the crystals evaporate at a slower rate than crystals without the coating. Notice how they never made measurements of a real jet engine at the pressures and temperatures at flight altitudes. That led Karcher and company to simulate the effect for stratospheric contrails, which are short-lived (lifetimes of seconds). A considerable increase in their lifetimes would be anything longer than 10 seconds. There is not enough water vapor in the stratosphere for a contrail to grow even if the initial particles lasted for a minute or more. You are barking up the wrong tree; the stratosphere is a graveyard for aborted contrails. Besides, there is nothing conclusive about their study because they use the word "would" twice in that sentence you underlined. That means the statement would be true if their simulation or theory was correct. That leads to the sentence you left out, which is the second quote above. They have no clue if this idea has any relevance to the chemical processes in the stratosphere in general. They were concerned with the chemical reactions that take place at the interface between the air and the ice crystal. Increasing the reaction time from 1 second to 10 seconds by increasing the lifetime of a crystal means they get ano order of magnitude increase in the perturbation. It doesn’t mean squat for a persistent contrail, which they were not concerned about anyway.

now I return you to canex's earlier quote:
"... but the difference so far has not been shown to be great enough to worry about. That does not mean that it won't be in the future."

The key words there are "so far” and the qualification that follows leaving the possibility that there is the possibility that aerosols may be considered important in the future. But compared to supersaturation, such coatings are basically irrelevant to persistent contrails.

No contradiction.

Now for your coup de grace quote:

"volatile particles may contribute considerably to ice crystal nucleation at temperatures below the contrail threshold value. This result is supported by observations of contrails and their microphysical properties for different fuel sulfur levels (Petzold et al., 1997)"

Do you know what the contrail threshold temperature is? It is the warmest temperature at which a contrail can form. Any temperatures below the threshold value should support contrails. The statement does not mean that volatile particles would cause the contrails to form at warmer than normal temperatures. This statement has nothing to do with abnormal contrails. One of the goals of the Petzold paper was to verify the theoretical calculations of how the crystal nucleation begins. And yes, they found out that volatile particles play a role in it when the temperature is below the threshold value. If it’s above the threshold value, there ain’t no water droplets to be nucleated.

You’re gonna have a try a lot harder, Curly, or start accepting the fact that all these trails are normal contrails. And the sky is not falling.

posted 03-11-2003 12:28 AM            

"This is what they really mean" and "This is what they're really saying" are arguments best left to Supreme Court judges ruling on Consitutional issues and safely away from the demonstrably confused.

And yet, after all this circular logic and courthouse posturing, you finish off with:

quote:

---

The key words there are "so far” and the qualification that follows leaving the possibility that there is the possibility that aerosols may be considered important in the future.

---

Flim-flam, back-peddling, covering your assets... call it what you will. But to my mind any scientist that can take the position that aerosols are 'unimportant', in this the year of our lord 2003 AD, is likely the same breed of 'scientist' that gifted the world with the Hydrogen Bomb (and, no, his name wasn't 'William', Mr. Brittanica).

Some scientists, and history clearly illsutrates this, define themselves by the amount of funding they can aquire for their Frankesteinian ambitions and by the velocity with which their kness hit the ground when their masters come calling.

On the other hand there is the occasional scientist that tries to achieve results that will benefit mankind.

I didn't enter into this discussion with you to discuss the reality of 'chemtrails' or to gain any insight into the basis of the Contrail Forecast model. I entered into it to discover what kind of man... which kind of scientist you were. A rigourous sceptic who nontheless is concerned with the future of the living planet and it's inhabitants? Or some yuppie striver houseboy who'd sell his own mother for a bigger SUV?

So. Now I know.

As for your last question; this forum's adminstrator publically stated that Dr. Minnis psoted on this forum. Having had access to user IP data during my time moderating on this site, I couldn't help but notice that 'Canex' logged in frequently using NASA resources. At the time, it seemed to be common knowledge. If you are not Dr. Minnis, now is the time to state so unequivocally and for the record (or forever hold your peace).

This is not a request for you to answer another question with a question, BTW.

Other than that, I think I've learned all I need to know with regards to NASA, public dislosure and the effects of aerosols on our climate and on our skies. Sadly, it seems we won't be forced into these awkward social situations in the future, Dr. Minnis.

Good luck on your selfless quest to secure the future of mankind.

posted 03-11-2003 08:55 AM            

I assume that your insinuations about my character, backed up by no evidence, mean that your preconceived notions about the chemtrails were not supported by the facts in this discussion. If you look hard enough, perhaps, you can find a pig that's turned into horse.

I have provided honest and well-researched information on contrail formation and properties here on my own time. Not on your coin or anyone eles's. This information is provided to inform the public at this board about the true nature of contrails. Other boards do not allow the truth to be heard. Nevertheless, a lot of people at this board are led astray by bogus assertions and misinterpreted observations that are reinforced by others who enjoy the excitement of a conspiracy theory regardless of its lack of basis in fact. I am not here to win a debate for debate's sake. If I am wrong, I will admit it. Yes, I can type a wrong number into an interactive web site with the best of them. But I won't sit idly by while my words are misconstrued and twisted or others' words are used for the wrong purposes. (Unless I don't it or am in a who cares mood.)

The notion that those cloud trails are chemtrails is a fantasy that actually causes needless worry to some people on this and other boards. It also stirs up some small number of readers against the government for no good reason. If you want to rail against the government, find a legitimate reason. Chemtrails are not bonafide.

It is a shame that you have such hostility to your government and NASA. There is a lot of uncertainty in the effects of contrails on climate. But despite the uncertainty, efforts are underway to find new propulsion systems and other means for mitgating their possible impact on climate and perhaps some day diminish the number of contrails in the sky and return blue skies where they are now so often obliterated with white lines.

William Teller is the guy who had an apple blown off his head with an H bomb.

It's a good thing you are not moderating any more. You can't be trusted with people's privacy.

posted 03-11-2003 12:46 PM            

You asked a question, I answered it. But yeah, all this "Gee, I wish NASA was my agency" and "What on Earth makes you think I'm this Minnis guy" BS doesn't do much to enhance your perceived honesty level, I'm afraid. Sure you're not Bob B?

quote:

---

I assume that your insinuations about my character, backed up by no evidence, mean that your preconceived notions about the chemtrails were not supported by the facts in this discussion.

---

On the contrary, there is clearly an abundunce of evidence on this thread with which the reader can make a preliminary determination of your sincerity (see above).

quote:

---

It is a shame that you have such hostility to your government and NASA.

---

Hostility? No, I'm simply asking questions and providing documentation. If one guy can put a government agency on the defensive so quickly, then there's clearly something to be defensive about.

quote:

---

efforts are underway to find new propulsion systems and other means for mitgating their possible impact on climate and perhaps some day diminish the number of contrails in the sky and return blue skies where they are now so often obliterated with white lines

---

Perhaps... someday. Not good enough. If these are just normal contrails, devoid of purpose, they could be rendered extinct by altitude caps and/or contrail supression additives right here and now.

If anyone in NASA or the USG had slightest inclination towards returning the atmosphere to something resembling earthlike, the least they could do would be a real-world pilot study on altitude caps and trail suppression.

But even with all this ever-increasing suspiscion and distrust, no one seems terribly interested in undertaking this fairly simple solution to their problems.

posted 03-11-2003 10:08 PM            

You think we should put additives in jet fuel? There's a novel idea on a chemtrail board. Like to suggest some additives?

Simple solutions?

Got any clues about how complex the air traffic system is? You need a good reason to alter the flight rules that govern the more than 13,000 commercial planes that fly above 25,000 ft every day over the US, even if it's to run an experiment. That does not even include the other thousands of planes that fly below 25 Kft. The larger the vertical maneuvering room, the safer the skies.

Any such experiment, like all large expensive projects, requires good, solid justification with consideration of all of the factors. A bunch of people whining about chemtrails is not going to cut it. If someone can show contrails significantly affect climate or health, then some type of experiment might get the nod. But so far, the beef or the smoking gun that shot the cow is not there.

posted 03-11-2003 10:27 PM            

quote:

---

You need a good reason to alter the flight rules that govern the more than 13,000 commercial planes that fly above 25,000 ft every day over the US, even if it's to run an experiment.

---

I said a pilot study. And no, I didn't mean studying the guys who fly the planes...

quote:

---

Any such experiment, like all large expensive projects, requires good, solid justification with consideration of all of the factors. A bunch of people whining about chemtrails is not going to cut it.

---

That's what I thought. Public outcry influence public policy? Heaven forbid.

quote:

---

Who are you by the way, since we are being so up front about identity?

---

Ask your buddy John Reynolds. He'll tell you. Depending on his mood, it will be either:

1. The guy that wrote The Mothman prophecies.

2. The guy that wrote The Matrix.

3. Some New-Age Guru named Drunvalo something or other.