Contrailb altitudes

[Luke Mc]

Hello
What is the lowest altitude and highest altitude you know a contrail to form behind the aircraft, what is the highest, e.g. would Concorde still leave a non pesistant contrail at FL500-FL600 on its run LON-NYC. I have seen a Concorde contrail once, but this was at FL300, I presume that that can be a common site down by the Bristol Channel as it approaces M1.0. I have only seen a contrail below FL200 once, but is that common below that altitude?
Luke

[Checkboard]

Plenty of stuff on the net about contrails - do a simple search, and ignore the "Chemtrail" stuff!

Contrail formation, duration and altitude
CONTRAILS - Scientific Studies

[ 05 September 2001: Message edited by: Checkboard ]

[Rockhound]

I've spent many summers as a geologist in the Canadian Arctic Islands and what often struck me was the common absence of contrails behind jet airliners that must have been flying at or near their maximum cruising altitude on routes between Europe and N America. Would this perhaps have been due to lower air temperatures at those high latitudes?
Rockhound

[Checkboard]

It probably has more to do with the relative humidity of the air at that latitude and altitude during that time of year.

[Rockhound]

Thank you, Checkboard, that makes more sense.
Rockhound

[None]

While I have not yet looked at the links above, I will say that I was impressed by the military weather forecasters a while back. During our mission briefings a weather sheet would be included which advised the "con levels." These predictions were accurate enough that we routinely kept the information in mind when considering tactics. It was common to see the con levels drop into the low 20s during the winter.