If you're in Houston right now, particularly on the North side, go outside and look up. See anything weird? Lots of long contrails or as some would say "chemtrails". Regular contrails disappear after a few minutes. "Chemtrails", on the other hand, linger for hours at a time. They spread and eventually fill the sky with a yellow like haze. Is anyone else familiar with this "phenomenon"? Is there something to this or is this just another wild conspiracy theory? Any thoughts?
Just came back from lunch and looked up, wow! I count at least 3 different "X" patterns clearly visible in the sky. Pretty cool looking.
im familiar with it and i posted something about it awhile back we have them ALL the time up here in austin.
Contrails that expand out.... Chemtrails......????? LOL......hey look out behind you, it is a gray alien. DD
It's winter a front just came through ... clear air + cold air = contrails lasting longer and you can see them longer. Mystery solved.
Wow...I saw several here in Fort Worth today(even now) as well. They were making Xs it looks like. It must be a conspiracy. Hmm.
also...contrails dissopate (sp?)...these just spread out across the sky and they are there all day. i saw them again today...it happens every day. i'm sure it happens on cloudy days too but i just can't see them.
EXACTLY! Thank-you they are around in the summer as well, but you can't see them as well because of the humidity and haze. The trails actually last longer when there is a decent amount of humidity in the air, you just can't seem them as well. It also depends on the angle of the sun and how interacts with the chem~ er vapor trail.
At the altitude these contrails are being created it does not matter whether it is winter or summer. Jet exhaust is very warm but it's very frigid that high and the water vapor in the exhaust forms into ice crystals almost immediately. The key element in how long the contrail persists is the humidity. Here is a nice article with related links: disinformation
well in the summer they appear just the same as in winter visibility and all, but they do probably spread out more in the summer they stay around just as long if its a humid or a dry day. they span all the way across the sky too i dont know about all the conspiracy theories but i know they are there and that they don't look like contrails that you normally see from jets. i read that link and it didnt really tell me much...i'm just curious what they are and if they are simply water vapor then why do they act how they do and why does it just look like they are like painting the sky with these things?
Contrails The condensation trail left behind jet aircrafts are called contrails. Contrails form when hot humid air from jet exhaust mixes with environmental air of low vapor pressure and low temperature. The mixing is a result of turbulence generated by the engine exhaust. Cloud formation by a mixing process is similar to the cloud you see when you exhale and "see your breath". The figure below represents how saturation vapor pressure varies as a function of temperature. The blue line is the saturation vapor pressure for ice as a function of temperature (in degrees Kelvin). Air parcels in the region labeled saturated will form a cloud. Imagine two parcels of air, A and B as located on the diagram. Both parcels are unsaturated. If B represents the engine exhaust, then as it mixes with the environment (parcel A) its temperature and corresponding vapor pressure will follow the dotted line. Where this dotted line intersects the blue line is were the parcel becomes saturated. If you are attentive to contrail formation and duration, you will notice that they can rapidly dissipate or spread horizontally into an extensive thin cirrus layer. How long a contrail remains intact, depends on the humidity structure and winds of the upper troposphere. If the atmosphere is near saturation, the contrail may exist for sometime. On the other hand, if the atmosphere is dry then as the contrail mixes with the environment it dissipates. Contrails are a concern in climate studies as increased jet aircraft traffic may result in an increase in cloud cover. It has been estimated that in certain heavy air-traffic corridors, cloud cover has increased by as much as 20%. An increase in cloud amount changes the region's radiation balance. For example, solar energy reaching the surface may be reduced, resulting in surface cooling. They also reduce the terrestrial energy losses of the planet, resulting in a warming. Jet exhaust also plays a role in modifying the chemistry of the upper troposphere and lower stratosphere. NASA and the DOE are sponsoring a research program to study the impact contrails have on atmospheric chemistry, weather and climate. http://cimss.ssec.wisc.edu/wxwise/class/contrail.html
