ktlight
1st July 2011, 08:05
FYI:
Living near airports might not only lead to residents suffering sleepless nights – they could also have terrible weather, scientists say.
For aircraft increase the chances of snow and rain when they take off and land, an extraordinary study suggests.
Apparently the effects of jet planes punching through clouds are similar to ‘cloud seeding’ operations, where ice crystals are created in the atmosphere to make it rain.
The findings - published in the respected academic journal Science - are based on satellite images of clouds around airports and computer models of cloud behaviour.
The side-effect of flying is likely to be most obvious around the world’s busiest airports, such as Heathrow where more than 1,200 planes land or take off every day.
The phenomenon occurs when aircraft smash through clouds containing 'super- cooled’ water - or water that exists as droplets of liquid at temperatures of minus 10 C or below.
As an aeroplane passes quickly through a cloud, the air behind the wings and propellers expands and cools rapidly.
These sudden drops in temperature can be enough to freeze droplets of super-cooled water - turning them into a stream of ice crystals.
Over time, ice crystals grow and affect neighbouring drops of water - creating a hole in the cloud that expands for several hours and increasing the chances of snow or rain on the ground underneath.
Dr Andrew Heymsfield, of the National Centre for Atmospheric Research in Boulder, Colorado, said aircraft increased the chances of snow when they punched holes in clouds after taking off and when they created 'canals’ in clouds when descending.
'Whether an airplane creates a hole or a canal in the clouds depends on its trajectory,' he said.
'When they climb through a super-cooled cloud layer, they can just produce a hole. But when they fly level through the cloud layer, they can produce long canals.'
The side-effect is more likely to affect areas around the world's busiest airports, such as Heathrow
The study found that super-cooled cloud layers are found with 62 miles of the world’s major airports at least five per cent of the time. The cloud seeding effects are more noticeable closer to the north and south poles
source to read more
http://www.dailymail.co.uk/sciencetech/article-2010003/How-aircraft-make-rain-snow--Planes-influence-local-weather-land.html
Living near airports might not only lead to residents suffering sleepless nights – they could also have terrible weather, scientists say.
For aircraft increase the chances of snow and rain when they take off and land, an extraordinary study suggests.
Apparently the effects of jet planes punching through clouds are similar to ‘cloud seeding’ operations, where ice crystals are created in the atmosphere to make it rain.
The findings - published in the respected academic journal Science - are based on satellite images of clouds around airports and computer models of cloud behaviour.
The side-effect of flying is likely to be most obvious around the world’s busiest airports, such as Heathrow where more than 1,200 planes land or take off every day.
The phenomenon occurs when aircraft smash through clouds containing 'super- cooled’ water - or water that exists as droplets of liquid at temperatures of minus 10 C or below.
As an aeroplane passes quickly through a cloud, the air behind the wings and propellers expands and cools rapidly.
These sudden drops in temperature can be enough to freeze droplets of super-cooled water - turning them into a stream of ice crystals.
Over time, ice crystals grow and affect neighbouring drops of water - creating a hole in the cloud that expands for several hours and increasing the chances of snow or rain on the ground underneath.
Dr Andrew Heymsfield, of the National Centre for Atmospheric Research in Boulder, Colorado, said aircraft increased the chances of snow when they punched holes in clouds after taking off and when they created 'canals’ in clouds when descending.
'Whether an airplane creates a hole or a canal in the clouds depends on its trajectory,' he said.
'When they climb through a super-cooled cloud layer, they can just produce a hole. But when they fly level through the cloud layer, they can produce long canals.'
The side-effect is more likely to affect areas around the world's busiest airports, such as Heathrow
The study found that super-cooled cloud layers are found with 62 miles of the world’s major airports at least five per cent of the time. The cloud seeding effects are more noticeable closer to the north and south poles
source to read more
http://www.dailymail.co.uk/sciencetech/article-2010003/How-aircraft-make-rain-snow--Planes-influence-local-weather-land.html