posted 01-25-2003 07:34 PM            

quote:

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Originally posted by Lulu:
And as one of our resident meteorologists, I'm sure FK is a wealth of meteorological information--that is if the data hasn't already been purged (;

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posted 01-25-2003 07:36 PM            

The pic I have in my e-mail with big fat trails look even lower in elevation.

>>Excellent pic. I have never honestly never heard of "projected halos".<<

posted 01-25-2003 07:38 PM            

quote:

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Originally posted by Lulu:
>>I just don't have the energy to go over all this old groud with new debunkers.<<

Don't know if FK is a debunker FLKook--he's a meteorologist that we know for sure.

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I am not sure how you define "debunker." I only seek truth. If I challenge things you post it is only so I can understand your point of view.

posted 01-25-2003 07:40 PM            

quote:

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The skies above the Southwest are typically too dry, and the skies above the deep South are too hot for extended contrail coverage.

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Hot on the Contrails of Weather
By Mark K. Anderson

2:00 a.m. May 15, 2002 PDT
Scientists have long suspected that airplane condensation trails -- the wispy, white tails found in the wake of high-flying jets -- form larger cloud banks that substantially alter the atmosphere's heat balance.

These jet-generated clouds, called contrails, may in turn play an important role in shaping our weather.

See also:

• NASA: That Rain Came From Yonder
• Green Houses: Not Just for Plants
• Hey Kid, What's the Weather Like?
• Read more Technology news
• Environment News Service: Unearth the dirt



However, testing this proposition has been tricky. Scientists can't just ground all the planes across, say, North America and then study the before-and-after data.

But, for three days starting last Sept. 11, meteorological researchers were presented with just such an opportunity when the FAA grounded commercial flights nationwide for three days following the terrorist air attacks.

And now it has emerged that the American climate was indeed noticeably different during those three days without air travel.

A team of climatologists presented their work Tuesday, showing that temperatures in the United States fluctuated by 1.2 degrees Celsius more when airplanes were grounded than when normal flight patterns prevailed. That is, planes in the sky dampen the variability between day and nighttime temperatures. More air travel, the researchers suggest, brings less meteorological difference between noon and midnight.

This research provides one of the strongest indicators that air travel itself changes our climate.

"We actually found a much greater change in temperature range for parts of the country that normally get the greatest contrail coverage," said David J. Travis, of the University of Wisconsin in Whitewater. His team presented their results at an American Meteorological Society conference in Portland, Oregon.

Large contrails, he said, only form when the cruising-altitude atmosphere is both sufficiently moist and sufficiently cool (somewhere in the range of minus 40 to minus 65 degrees Celsius). The skies above the Southwest are typically too dry, and the skies above the deep South are too hot for extended contrail coverage.

These factors plus the varying density of air traffic over different parts of the country combine to make the skies in the Midwest and Northeast -- and, to a lesser extent, the Pacific Northwest -- particularly laden with contrails.

In such contrail-heavy portions of the country, Travis' team found that during Sept. 11-13, the difference between day and night temperatures increased even more. The Midwest and Northeast experienced a "contrail effect" of 3 degrees Celsius, more than twice the national average.

And as anyone who follows global-warming forecasts knows, it only takes climatic changes of fractions of a degree Celsius to yield widespread results.

Yet, Travis added that the new data does not suggest that contrails offset or enhance global warming. Other research has suggested contrails have a global-warming effect. But Travis' data addresses variability between day and night temperatures, not an overall warming or cooling trend.

"It complicates the debate," he said.

Conclusions are more certain on the regional scale, he added. As air traffic increases over some regions of the world, the increased density of contrails will likely bring even smaller differences between daytime and nighttime temperatures, and that will alter the local environment.

posted 01-25-2003 07:43 PM            

quote:

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Originally posted by Lulu:
AHEM FK--you have included FLKook's quote in the same bracket as my quote.

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that was because I quoted off your post. Oops.

posted 01-25-2003 07:47 PM            

quote:

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Originally posted by Lulu:
[BI first noticed them the fall of 2000 FK.[/B]

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So if I show you pics from before that, will that convice you of anything?

posted 01-25-2003 07:50 PM            

quote:

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Originally posted by FLKook:
This is pertinent because the halo's seem to only show up with the "persistent contrails"

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Well, I've seen halos when the sky appeared absolutely clear. see this link if you want ssome info on how common halos are.
http://www.sundog.clara.co.uk/halo/common.htm

posted 01-25-2003 07:57 PM            

Yes, FK, please post some halos pre 2000 above the Kelowna area taken mid-summer. That would convince me that these halos (that I witnessed on almost a daily basis, both night and day, from fall 2000 until spring 2002) are more common than thought...and just perhaps nothing sinister is going on overhead...

posted 01-25-2003 07:57 PM            

Good night,

posted 01-25-2003 08:05 PM            

Good night again,

F.K.

posted 01-25-2003 08:14 PM            

http://www.stecf.org/~rfosbury/home/natural_colour/sky/halos/Wendelstein/wendelstein.html

posted 01-26-2003 08:39 AM            

quote:

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Originally posted by Lulu:
FK why is it that Mark's "heliac arc" is broken up? and not a continuous line like all the other arc pics?

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As you will probably notice from the halo site I posted, most things are not visible at the same time. For instance, I've seen a sundog on one side of the sun, but not the other, It is all a question of where the proper size/shape ice crystals are with respect to your location. It should not amaze anyone that sometimes only partial halos are visble.

F.K.