Originally posted by luxordelphi
reply to post by Chadwickus
I had provided a link with a few simple tips on telling chemtrails from contrails. I selected a few quotes from the link to post.
Chemtrails or Contrails?
As pointed out by ProudBird, the trouble with this link is that they fail to mention that it is not humidity, but
that determines whether a contrail can persist or not. As air
pressure and temperature decreases, it's ability to hold water vapour decreases. When air is forced higher into the atmosphere, the pressure
decreases, the air expands and cools and once it can no longer hold water vapour it condenses into clouds.
This is what happens in front of an approaching front, which is why you get cirrus formation, along with many other cloud types. This same mechanism
of uplift increases the relative humidity of the atmosphere making contrail formation more likely. This does not mean that conditions for contrails
occur prior to fronts, just that it often makes conditions more favourable. Here is a pretty good explanation of weather formation
including fronts for a layperson.Aviation Weather -
Measurements of relative humidity in a persistent
Cirrus clouds and aircraft contrails in the upper troposphere consist of ice particles with diameters ranging from less than 1 μm to more than
1000 μm. These ice particles directly and indirectly affect the earth's climate (IPCC, 2001). The frequency, duration, and size distributions of
cirrus clouds and contrails depend strongly on the relative humidity with respect to pure ice (RHi) distribution in the upper
Also I'm not saying that what you are seeing is not any form of geo engineering. Just that ground conditions don't always determine atmospheric
conditions at high levels. Therefore you cannot assume that low humidity at ground level precludes contrail formation in the upper atmosphere. I
would recommend reading about weather formation from many sources, as a random person on a chemtrail site often knows just as much or less about
meteorology as you do.
Where does it say that it gets more humid the higher in the atmosphere you go?
It doesn't always, but it can. Take for example, these
near the site and time of the pics in the OP (the measurements closer to the time than the data the OP used). In this case, the
surface humidity was moderate, but you can see that at varying pressures at different altitudes, the relative humidity can vary considerably. Using
these observations, you can use the Appleman chart to determine that contrail formation was likely at typical airliner altitudes.
Predicting Contrails Using an Appleman Chart
As a better example, here is the
balloon measurements from
Las Vegas, Nevada
a few days ago. They show relatively low humidity at ground level (13%), but much higher relative humidity higher up (66% @
6341m) and at an altitude of 10,480m (34,383 feet) typical of airliners the conditions were conducive for contrail formation.
That's why they are so wierd and have all these wierd optical effects - because they are made from chemicals.
Would you say that this
is a weird optical effect caused by chemicals?
I admit, it does seem pretty weird. And if you define water as a chemical, then you could say it is caused by 'chemicals' as it is due to the
refraction of light through water. This can occur through both water and ice crystals. This is why cirrus (natural or manmade) cloud can produce
'rainbows' by refracting light from the sun or even the moon. These are both from natural cirrus and cirrostratus cloud.
I'm not trying to debunk or offend anyone. But I hope I can promote learning and understanding of the topics at hand
edit on 15/3/12 by
Curious and Concerned because: added las vegas balloon measurements