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Author Topic: cloud trails for aeroplanes  (Read 5445 times)

paul.fr

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cloud trails for aeroplanes
« on: 06/04/2007 20:59:24 »
in the northern hemisphere we see many cloud trails in the sky from passing aeroplanes, why is this not as common in the southern hemisphere?


 

another_someone

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cloud trails for aeroplanes
« Reply #1 on: 06/04/2007 22:35:49 »
As far as I am aware, there is no reason why an aircraft would be less likely to leave cloud trails in the southern hemisphere; but it may be that their is less air traffic in the southern hemisphere (simply because there is less land mass, and fewer affluent countries).
 

lyner

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cloud trails for aeroplanes
« Reply #2 on: 07/04/2007 00:00:22 »
Which latitudes does your experience  cover?
Your observations may not be 'symmetrical' in both hemispheres (+/- the same degrees of lattitude).
It may also be more humid in the UK than in parts of Australia, for instance.
I think another_someone's answer may well be the right one, though.

« Last Edit: 07/04/2007 00:04:48 by sophiecentaur »
 

paul.fr

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cloud trails for aeroplanes
« Reply #3 on: 07/04/2007 00:49:42 »
Well, the UK skies are full of vapour trails yet they are very rarely seen in Australia. Is it geological. Australia is relatively flat and the UK is not. Or is it atmospherical / climatic , Australia is dry and drought a real problem due to lack of rain. Wheras the UK has a wetter climate.
 

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cloud trails for aeroplanes
« Reply #4 on: 07/04/2007 03:24:39 »
We see them here all the time, I have never been anywhere else to know the difference!
 

another_someone

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cloud trails for aeroplanes
« Reply #5 on: 07/04/2007 11:14:05 »
Well, the UK skies are full of vapour trails yet they are very rarely seen in Australia. Is it geological. Australia is relatively flat and the UK is not. Or is it atmospherical / climatic , Australia is dry and drought a real problem due to lack of rain. Wheras the UK has a wetter climate.

But the UK is a hub of transatlantic flights - not only flights travelling from the UK to the USA, but flights stopping off in the UK from Europe of the East (middle and far) before flying on to the US (and ofcourse, flights doing the same in reverse).  The UK skies are some of the most congested skies in the world.  Australia simply would not compare.

Unless you are talking about something like Mount Everest, it will have zero impact at the altitudes that aircraft are leaving vapour trails (20,000 to 30,000 feet).  Not even sure how much difference humidity is going to effect it, since what you are talking about is humidity at ground levels.  The vapour trails are being left at altitudes where air temperature is below freezing, so there would be no natural humidity at that altitude anyway, and the vapour trails are caused by water generated by burning fuel in the engines of the aircraft, and that water is then immediately freezing to form a trail of ice crystals.

What might have an impact is the ambient temperature.  If the outside temperature is warmer (i.e. above freezing) then it is unlikely you will see vapour trails - but at 30,000 feet, I am not sure there is anywhere in the world that would be above freezing at that temperature (maybe someone might tell me I am wrong about that - but to have somewhere in the world where you cannot get vapour trails at 30,000 feet, it would have to be somewhere where you could not get cloud formation at 30,000 feet - and anywhere I have seen, clouds will form at even lower altitudes than that).

The question I would have is, if looking up at the skies in the Australian outback - how many aircraft cross that area of sky, and how far are they going (short hop flights may not necessarily fly high enough to encounter freezing conditions - so how many intercontinentals, or even medium distance international flights, are overflying the outback)?
 

paul.fr

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cloud trails for aeroplanes
« Reply #6 on: 07/04/2007 15:28:46 »
So the major factor is the volume of air traffic, Thanks George.
 

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cloud trails for aeroplanes
« Reply #6 on: 07/04/2007 15:28:46 »

 

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