posted 08-08-2002 07:10 PM            

Jet trails linked to temperature shifts
Halt in air traffic after Sept. 11 allowed closer look at contrails

LONDON, Aug 7 — Clouds formed by trails of water vapor from jet aircraft affect temperatures on the ground, scientists say. Although researchers had suspected the streams of condensation and ice crystals known as contrails had an impact on temperatures, they were not able to test the theory because air traffic over the United States never stopped for any extended period until the Sept. 11 terror attacks.

THE ATTACKS prompted U.S. authorities to ground all commercial aircraft for three days — which allowed researchers to test the impact of contrails.

After analyzing maximum and minimum temperatures over the United States during the grounding period and comparing it with weather records for the same period from 1971 to 2000, they found the change in temperature range was 1.1 degree Celsius, or 2 degrees Fahrenheit, above the 30-year average.

The research, published in Thursday’s issue of the journal Nature, was conducted by Andrew Carleton, a geography professor at Pennsylvania State University; David Travis, a climatologist at the University of Wisconsin at Whitewater; and Ryan Lauritsen, who was an undergraduate at Whitewater when the study was conducted.

“September 11-14, 2001 had the biggest diurnal temperature range of any three-day period for the past 30 years,” Carleton said.

The diurnal temperature range is the difference between the nighttime low temperature and the daytime high temperature, usually for a given day.

Contrails, which can last as long as several hours, alter temperature just like high clouds — they reflect sunlight from above and trap the heat from below.
Without the contrails, the daytime temperature would be slightly higher and the night temperature would be lower, creating the increased range between the lowest and highest temperatures.
The research is reported in Thursday’s issue of the journal Nature.
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Now Nature is a very well respected scientific journal. You just have to wonder about the quality of peer review on this particular article. While not disputing the temperature variance that was observed, it is inconceivable that all such trails are referred to as "ice crystals".

The same story was carried on CNN yesterday evening, complete with a video of a jet spewing intense trails.

At least it's bringing the issue into public attention, and perhaps closer scientific scrutiny.

posted 08-10-2002 03:53 PM            

A thought for the conspiracy theorists among us... Is it possible that TPTB are trying to divert attention away from who is actually doing the spraying by pinpointing the blame onto the commercial airlines?

Here's the link to that particular post and a few quotes by the posters following. http://www.chemtrailcentral.com/ubb/Forum1/HTML/000877.html

Sore throat: 9/11/01
Today there was certainly a monumental loss of innocent lives in America, and inevitably it will bring a change of life as we knew it.
The grounding of all COMMERCIAL aircraft is absolutely unprecedented.
For those concerned about the spraying of our skies, this unique situation affords an opportunity for careful observation. Now would be an excellent time for all those concerned to meticulously record their observations on the inevitable return of white skies. Couple your observations with atmospheric soundings - Skew-T diagrams - to establish whether physical conditions are appropriate for persistent trails.
In the memory of those who have died, perhaps we will be able to gain insight on a particularly insidious form of domestic terrorism.

Ellyn: 9/12/01
Spokane, Washington and the vast surrounding area was heavily sprayed yesterday. Today I observed a thick chemtrail-created haze and numerous chemtrail-created clouds, but no jet aircraft. Spokane was sprayed very heavily last week also.
I'd like to make a note that although I post my chemtrail observations from the Spokane area and therefore often speak of the heavy spraying in Spokane, the actual area being sprayed is extremely broad.

Afraidofsunlight: 9/12/01
Hello,
The dust and chem-flake's are so visible at certain time's of the day that you don't need shade's.Early morning and late afternoon.Dieing tree's placed between yourself and the chem-sun are a great backdrop.
Toilet bowl ring-round the horizen.The sprayer's were out before dawn,stop and start.They left us a lovely X right over Baltimore.Lot's of small chemtrail's.By late afternoon the magic cloud's had appeared.They are melting as I write this.

Roman: 9/12/01
I seen the first chemtrail at 9AM this morning,It was one of those west to eastlong wide dripping kind.It quickly spred and remained most of the morning. By noon it was business as usual over the valley.Tonight we have the normal chem dome. Yesterday I seen no trails at all . roman...

David: 9/12/01
Northern Calif/Lake Co...... Blue skies here are quickly disappearing this a.m. Being replaced with thin wispy, dripping "clouds" all in rows and filling the sky. They are forming over our county and being blown towards the Sacramento Valley. No planes heard or visible. HAARP

Delphi: 9/12/01
Pen, HAARP WAS turned on yesterday to maximum power at 3:15 PM PDT...at 6.965MHz Pulses 6.25 with dual pre-tones with short 15 second pauses. There was particulate matter, strands, and wispy formations and dirty, chem style cloud remnants in NW Louisiana. Additionally,my colleague may have on photos, "some" type of craft making individual circles of spray patterns in afternoon. Blessings, Joanne

Catnip: 9/12/01
I think one thing that can be ruled out is the hypothesis that the chemtrails are being created by increased air traffic or even commercial airlines since all of us know that these last two days there have been no commercial air traffic flying due to the terrorist attacks.
From what I hear the airliners are still waiting to hear when they can get back to business so this is an ideal time for us observant folks to gather in as much information we can as to the identity of the sprayers.

Top Gun: 9/12/01
I'll tell you what was flying, CatNip-
F-16s, F-15s, AWACS, KC-135's, and KC-10s. That's pretty much about it. The military has owned the airspace over the USA since a few hours after the attack.
We (that includes me) have been flying in combat air patrols over the skies of the USA since a few hours after the attacks. We've been sitting on alert at the end of many runways in this country, just in case if anyone else gets any stupid ideas. I've been privy to enough info in the last 24 hours to know that we are doing the right thing.

posted 08-19-2002 10:39 PM            

.....Contrail activity is what you observed, nothing more...nothing less.....

OK. So let's just say, for purposes of absolute clarification here, that this *contrail activity* to which you refer is just that - period - as you so emphatically state.

I infer from this that you would not therefore think that this *contrail activity*, to which you very specifically refer, is becoming a bit of an issue, if, in FACT, said activity is what people in many regions are observing to be spreading out and completely OBLITERATING blue sky over their regions day after day after day, up to 25 DAYS PER MONTH this summer.

In other words, if the sky-obliterating MESS people are witnessing daily over their heads is EXCLUSIVELY the result of *contrail activity - nothing more, nothing less* - then people should not be concerned that the appearance of our skies is being completely TRANSFORMED by this *activity*. Because it's only *contrails*.

Is this what you are implying? Or are you going to dodge the question here like so many others of your orientation to this matter?

posted 08-25-2002 09:45 AM            

Still no takers, I see.

posted 08-26-2002 08:13 AM            

"These are not condensation trails to the dismay of Contrail and others that think they are. A condesation trail dose not spread and fall to the earth leaving a white haze to blanket all of creation. It never has in the past and never will"

OK, Mr. Contrailologist. Here's what every commercial pilot will tell you. Contrails do spread. They often spread up to 4-5 times wider than the aircraft that left the contrail, and under the right circumstances, they will even "feed" cirrus clouds.

posted 08-27-2002 06:56 AM            

OK. So let's just say, for purposes of absolute clarification here, that this *contrail activity* to which you refer is just that - period - as you so emphatically state.

I infer from this that you would not therefore think that this *contrail activity*, to which you very specifically refer, is becoming a bit of an issue, if, in FACT, said activity is what people in many regions are observing to be spreading out and completely OBLITERATING blue sky over their regions day after day after day, up to 25 DAYS PER MONTH this summer.

In other words, if the sky-obliterating MESS people are witnessing daily over their heads is EXCLUSIVELY the result of *contrail activity - nothing more, nothing less* - then people should not be concerned that the appearance of our skies is being completely TRANSFORMED by this *activity*. Because it's only *contrails*.

Is this what you are implying? Or are you going to dodge the question here like so many others of your orientation to this matter?

I'm asking a very straight question. I'd really like a straight answer - for once.

The question is:

It is __OK__ that our skies are, at this point, virtually obliterated, day after day after day, by the results of *persistent, spreading contrail activity*, right? There is __no problem__ with that, right?

Please answer, directly, this one question. I don't think that's too much to ask.

posted 08-27-2002 08:57 AM            

From yesterday's "just contrails":

Old trails line up and form large cloud. There are many trails merging together in this shot:

This little area was built up by "just contrails" until it joined the main cloud mass near it:

posted 08-27-2002 03:19 PM            

Most of those "obliterated" skies weren't formed from contrails. Rather, the contrails formed due to the skies. What do I mean?

Well, it's obvious that most of you see alot of contrail activity on days that the sky is "obliterated". But you falsely attribute this to the contrails, making the assumption that contrails=obliterated skies.

Actually, contrails or not, the skies would have formed overcast or broken cirrus layers regardless, due to the specific conditions at altitude. The contrails formed as a byproduct of those conditions. If conditions are humid enough to form cirrus decks, then it's pretty safe to figure that contrail formation is very possible as well.

That book I was looking at specifically addressed that issue. It showed a photo of a cirrus overcast layer, with a contrail going through it. The caption read something like "often conditions that allow cirrus layers will frequently be conducive to contrail formation as well".

The simple thing to remember is that if contrails can form, then clouds can form. And vice versa.

posted 08-27-2002 05:14 PM            

Likewise, the increased production of contrails impacts the local climate at some scale. If it continues, that impact may be measureable if is not already (see Travis article). If it is really having a significant effect, then we should be concerned about it.

posted 08-27-2002 07:08 PM            

quote:

---

Overall, yes, contrails do affect climate to a certain degree. But it's really not as much a threat, if any, to our environment as the many other sources of man-made problems, to include vehicle and factory emissions, etc.

---

It's where the exhaust is emitted that makes it a much bigger threat.

LINK

posted 08-31-2002 07:05 PM            

Gas Mask: Aircraft pollution does affect the upper atmosphere, but rather than saying that the aviation industry is being reckless, it's quite the opposite. Jet engines today (especially in the US, Canada and Europe) use high-bypass turbofans.

High-bypass jet engines utilize a large fan mounted ahead of the jet turbine core. The fan serves two purposes: provide thrust, and provide air to the turbine core. At lower altitudes, the fan provides up to 3/4s of the thrust, while this is reduced at high altitudes to about 1/4 to 1/3 of the thrust.

In contrast, low-bypass turbofans, and turbojets use much more fuel to create the same amount of thrust. A low-bypass turbofan does provide some fan thrust, but most of the thrust comes from the core, which is where the fuel is burned. A turbojet does not have a fan, and 100% of the thrust is developed from combusting fuel.

The result of using high-bypass engines is greatly reduced fuel consumption (and a corresponding decrease in pollutant emmissions), less noise, and more power. The high-bypass turbofan has led to the standard of two-engined jumbo jets versus the older traditional design of four engines.

Next on the horizon, and being researched, are engines that use hydrogen as a fuel, and produce only water vapor. They are still having difficulties with several issues, namely dealing with the extremely low temperatures of hydrogen fuel (which makes the fuel system components very brittle and thus prone to malfunctioning or failing) and handling issues (since hydrogen fuel is much more volitle than hydrocarbon fuel).

posted 09-01-2002 02:33 AM            

High-bypass turbofans: Generally are very wide and short, with an obviously large fan. These engines produce about 2-3 times the thrust of a similarly sized turbojet, but burn half the fuel. They are also much quieter. Every modern airliner is made with high-bypass turbofans.
http://www.airliners.net/open.file/269003/M/

Low-bypass turbofans: Have a fan out front, but are cigar shaped and narrow. Turbofans started appearing on aircraft in the early 1960s. Most aircraft originally fitted with turbojets were re-engined with low-bypass turbofans. 1960s and 1970s vintage airliners typically have low-bypass turbofans, including the 727, DC-9, and the 737-200. These engines have a reduced fuel burn, but don't produce much more power than a turbojet. They are also significantly louder than a high-bypass engine, and most aircraft equipped with low-bypass engines are hampered by Stage II noise regulations.
http://www.airliners.net/open.file/269114/M/

posted 09-01-2002 02:37 AM            

Pacer
Quote: "Actually, contrails or not, the skies would have formed overcast or broken cirrus layers regardless, due to specific conditions at altitude." NOT EVERY DAY OF THE WEEK 24/7! Is this part of the new script? I watch them being formed every single day out of 'thin air' over Puget Sound. If there were No jets mucking up the sky it would stay clear for several days in a row.

posted 09-01-2002 03:14 AM            

The reasons for contrails forming additional cloud cover is that they form in supersaturated air that is moist enough to support cirrus clouds but not moist enough to form them.

U/T, I don't think you can understand plain english...

seriously....

BTW, pacer...

JP-7 is hydrocarbon-based

is that the stuff that has R-134-A in it...