Why are aeroplane vapour trails in the sky so common in London, yet we don't see them in Australia?

Question

This question is asked from the perspective of a person standing on the ground, looking up.

Answer 1

Nakita, you may just be in the wrong place to see contrails. If you are close to Sydney, for example, there aren't many (or any) aircraft flying overhead. They are all landing, and low-flying aircraft do  not make contrails.

Here is a way for you to maybe see some contrails in Australia.

Get a map and see where you can go that is between two cities that have jets that would fly high between. For example, if you lived in Sydney, check on the flights between Melbourne and Brisbans. They are over 500 miles apart, and probably have fairly frequent flights between them. Find out when they leave the two cities, and you head for Lithgow, NSW. There, with a  pair of binoculars you should be able to see aircraft at altitiude, making contrails. If you don't live in Sydney, find other cities and do the same thing.

I live in Charleston, West Virginia, and all of the flights leaving Washington, DC that head west fly over us. All of the flights between Pittsburgh or  Cleveland heading south fly over us, plus the returns. Most of the time, there is at least one contrail overhead of us, and sometimes 10 or more. Not all of the time are there contrails. Some days there are very few, on other days, there are many.

Regards,

Dan

Answer 2

Most likely due to the higher average humidity in London compared to Australia.

Answer 3

Maybe in Australia water vapour is not visible.

Answer 4

Dan and Fluffy are on track but to simply state the answer.

Many aircraft over fly London, on cross Atlantic flights. So you have many aircraft above you at altitudes creating contrails.

Few if any cities in Australia would be flown over.  Their either coming or going.  We have the same thing here in Singapore.  While it's a very active Hub, there's few if any flyovers.  If a contrail appears in the sky people freak out.  (I seem to remember it even making the newspaper once)

If you are in the Midwestern US there are almost more contrails than clouds.  Due to the east west traffic.

NOTE

If humidity at ground level was the cause for appearance of contrails.  Singapore would be full of them.  AS to humidity at altitude, if you have clouds you have humidity.

How-some-ever, contrails are formed by moisture created by the engine, i.e.

The main products of hydrocarbon fuel combustion are carbon dioxide and water vapor.

At high altitudes this water vapor emerges into a cold environment, and the local increase in water vapor can push the water content of the air past saturation point.

The vapor then condenses into tiny water droplets and/or deposits into ice. These millions of tiny water droplets and/or ice crystals form the vapour trail or contrails.

The energy drop (and therefore, time and distance) the vapor needs to condense accounts for the contrail forming some way behind the aircraft's engines.

The majority of the cloud content comes from water trapped in the surrounding air.[citation needed] At high altitudes, supercooled water vapor requires a trigger to encourage deposition or condensation.

The exhaust particles in the aircraft's exhaust act as this trigger, causing the trapped vapor to rapidly turn to ice crystals. Exhaust vapour trails or contrails usually occur at above 8000 metres (26,000 feet). where the temperature is below -40°C (-40°F).

SO, if you have jet planes flying over at Altitude, you will see vapor trails.  No planes, no contrails!

Answer 5

Australia is a dryer place than UK, so with less humidity in the air, contrails will evaporate and dissipate faster.

There is also more air traffic in densely populated Europe.

Answer 6

Contrails are long "trails" water condensation (con-trails), caused by the relatively warm air coming from the jets of large aircraft. How much condensation results from an aircraft depend on a few factors, but chiefly air temperature and humidity. Note that earlier I mentioned "relatively warm air". While contrails are indeed common throughout australia, they may be a little less pronounced due to Austrlalian atmospheric conditions, but they will be there if you're in the right spot.

The temperature at 30,000 feet is generally cold enough to produce contrails. Also, London is in the flight path between Europe and the United States, so while aircraft departing heathrow will have insufficient altitude to produce the effect, those departing from say Stipol, Amsterdam will be high enough to create contrails by the time they pass over London.

If you look on a map of australia, Sydney is not in any domestic flight paths between capitals. i.e. A flight from Melbourne to brisbane passes Sydney 300km to the west. If you were in the vicinity of Orange, NSW, you would undoubtedly see them.

Hope that helps!

Answer 7

All wrong answers so far. Can't tell ya why YOU don't see em down under. But they sure are there. Flown to Australia a ton. Plenty of contrails. Same as anywhere in the world, vapor in the atmosphere varies from day to day. h**l, from hour to hour. There are many days when a vapor trail cannot form over london either.

Answer 8

terain is flatter in aussiland... also London is major internatinal turofair to europe and asia... No one flies thru australia... never herd of 5hr layover in Melbourn... ha

Answer 9

Because atmospheric conditions are so much different in Australia. Check out this YouTube clip of a Virgin Blue E170 landing at Port Macquarie. You will see the conditions and should understand it. http://www.youtube.com/watch?v=PpUftG_mx...

Answer 10

Generally most aircraft flying above FL300 30,000 feet will leave a contrail.  It depends on the weather conditions the length and the amount of time that it stays together.  It's because of the Air Traffic Density that you do not really see too many contrails in Aus compared to London.  Their are just more a/c flying higher in that area.