Chemtrail Question

Just a quick comment and question.

I have been looking up at Chemtrails for about 2 years now, and I do agree that something is going on, but what I dont know.

Some aircraft have little or no exhaust gas trail and some have a trail that goes from horizion to horizion. I dont know if this has to do with the age of the craft or its fuel economy, but some thing is going on!

My question is why are there no Chemtrails at night?

I see them all the time in the day, but not at night. Is this due to humidity or air temp being less at night.

Just wondering

Thanks johnboy

Well, johnboy, there are certainly a large number of threads here devoted to the chemtrail issue. I don�t agree that there is something going on.

What you have observed are simply contrails. All aircraft engines produce two main exhaust compounds. CO2 and H2O. At typical flight altitudes, the air temperature can be around -47 degrees F. That is pretty cold. As the hot moist exhaust exits the airplane engine it cools off rapidly and the excess moisture �condenses� into ice crystals. At that point the ice crystals will behave exactly the same as a cloud formation at the same altitude, since they are both made up of the same thing (ice).

At the temperature, and at the reduced air pressure at flight altitudes, a small amount of moisture in the air can make a huge difference in the relative humidity (or more correctly the relative humidiy with respect to ice or RHi)

If the RHi is low, then the ice crystals rapidly sublimate back into the atmosphere and you get a short lived contrail.

If the RHi is around 100%, you get a long lived (or persistent) contrail.

If the RHi is over 100%, then you get a persistent contrail that can initiate the formation of upper level cirrus clouds.

How can this happen? Air with a RHi over 100% is referred to as �supersaturated.� Generally at flight altitudes, the air can become supersaturated because there is not a whole lot of particulate matter up there to initiate ice crystal formation. Airplane exhausts also include a small amount of soot particles with the moisture.

The reason that you see more contrails in the daytime are probably based on a number of factors.

• increased air traffic during the day. More traffic = more contrails
  
  
• Maybe you haven�t noticed them as much because they are harder to see at night.
  
  
• Diurnal cycles in the atmosphere, including fluctuations in the barometric pressure, relative humidity etc. at flight altitudes. (to answer your question) I believe that his phenomenon has been documented by meteorologists.
  

Two other things to keep in mind

1. the volume of air traffic overhead has grown unbelievably over the past ten to fifteen years. More planes = more contrails.
   
   
2. Modern jet engines are much more powerful and fuel efficient then they were a few years ago. This means that more of the fuel is converted to exhaust gasses. Whereas before you had engines that produced a great deal of soot and smoke, and les water in the exhaust, the newer engines burn fuel more completely, thus producing more water in the exhaust stream then before. More water = more contrails.
   
   
   
   
   
   [Edited on 1-6-2004 by HowardRoark]

johnboy i disagree with HowardRoark that all chemtrails can be explained as harmless exhaust, as he did so nicely above , I do think there's something more to it, just don't know what either...but to answer your question, chem/con trails do occur at night. There are best seen when there is a full or almost full moon and the night sky is fairly lit. I have personally witnessed a few night trails and actually find them to be quite pretty at night.