Volcano Ash cloud

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Shoulder hopper
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Volcano Ash cloud

Post by Shoulder hopper » Tue Jun 14, 2011 7:35 am

I thought you fellas might be able to enlighten me on this.

I know that our weather travels from our west to east and that Chile is across the Pacific to our east, so how is it that the ash cloud can come against the normal weather flow?

Is it because the cloud is so high and the jet stream travels in the opposite direction or has the cloud gone right around the globe first? I thought they showed a sattelite picture the other night and the cloud was travelling east but I may have been mistaken. As this goes against what I have always believed with weather patterns, I was hoping that one of you learnerd people could set my thinking straight on how this is happening. Thanks SH

alakaboo
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Re: Volcano Ash cloud

Post by alakaboo » Tue Jun 14, 2011 8:51 am

The cloud is travelling from west to east, it has gone across Argentina, the Atlantic and around the southern ocean before getting here.
Image
(That's South America)
The jet stream is doing 30-50 m/s at that height, between 8-12km.
Shoulder hopper wrote:they showed a sattelite picture the other night and the cloud was travelling east
that would be consistent, no?

brendo
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Re: Volcano Ash cloud

Post by brendo » Tue Jun 14, 2011 3:07 pm

ive been wondering about this as well. but it affected nz first, then melb, now adel, and heading for perth, so is going west :? how is it so? jet stream also goes west to east, or is there one heading east/west?
paging mr shearer paging mr shearer.....

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oldman
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Re: Volcano Ash cloud

Post by oldman » Tue Jun 14, 2011 3:57 pm

brendo wrote:ive been wondering about this as well. but it affected nz first, then melb, now adel, and heading for perth, so is going west :? .
I think that is all true brendo, but I surmised that NZ was first affected because it is at much lower latitudes than Oz, and that there have been low pressure systems traversing under oz which have been pushing antarctic air up into the tasman (and then nz as the weather systems move east)

Don't know if it panned out that way, but I was able to quell my curiousity with that thought.

Here's a question for some mug though. From the starting point of the volcano, which is closer to Sydney? East to west or west to east.

A lifetime of looking at maps, always with the americas on the right hand side, can lead one to subliminally think that the world just drops off the page at that point, instead of heading round to meet africa not that very much further to it's east. Looking at projections of maps instead of squashed-ball-like globes gives you a distorted view of how and where countries are.

I'm gonna go look for this ash cloud on the interwebs.

Back to the other question, is the jet stream only west to east. Meteorologists often talk about surface lows and upper air disturbances. Dammit, I'm looking this up. Help me google!
Lucky Al wrote:You could call your elbows borogoves, and your knees bandersnatches, and go whiffling through the tulgey woods north of narrabeen, burbling as you came.

alakaboo
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Re: Volcano Ash cloud

Post by alakaboo » Tue Jun 14, 2011 4:20 pm

I think Olds was right, it was a latitude thing originally, then lower level stuff spreading it onto mainland Oz.

The jetstream direction and speed is dependent on latitude, I believe. As far as I could find out this morning, it is always west to east at that latitude.
http://www.sciencemediacentre.co.nz/201 ... lcano-ash/
Damn, 1000th post wasted.

Donweather
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Re: Volcano Ash cloud

Post by Donweather » Tue Jun 14, 2011 4:37 pm

oldman wrote:Here's a question for some mug though. From the starting point of the volcano, which is closer to Sydney? East to west or west to east.
OK, here goes my amateur response:

Given that all airlines fly east from Sydney to Chile, you would expect this to be the shortest route.

And by my calculations, the great circle distance from Sydney east to Chile is approximately 11,700km. The total circumference of a great circle is approximately 40,000km, hence the distance from Sydney west to Chile would be of the order of 28,300km.

Note that all of the above assumes great circle paths and me just thinking about it now....you wouldn't go west from Sydney to Chile on the opposite great circle path!!!

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oldman
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Re: Volcano Ash cloud

Post by oldman » Tue Jun 14, 2011 5:31 pm

Donweather wrote:
oldman wrote:Here's a question for some mug though. From the starting point of the volcano, which is closer to Sydney? East to west or west to east.
OK, here goes my amateur response:

Given that all airlines fly east from Sydney to Chile, you would expect this to be the shortest route. Would that be east or south south east if you are drawing great circles?And by my calculations, the great circle distance from Sydney east to Chile is approximately 11,700km. The total circumference of a great circle is approximately 40,000km, hence the distance from Sydney west to Chile would be of the order of 28,300km.

Note that all of the above assumes great circle paths and me just thinking about it now....you wouldn't go west from Sydney to Chile on the opposite great circle path!!!
Too damned smart you are. No, I was thinking east to west versus west to east, which would be much closer, parallel to the latitudes.

Here's an example of those damned mercator projections flattening out the globe and distorting my thinking. The other way around that great circle would take you somewhere over what, London? Middle East?

Oops, I think my head just exploded.
Lucky Al wrote:You could call your elbows borogoves, and your knees bandersnatches, and go whiffling through the tulgey woods north of narrabeen, burbling as you came.

brendo
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Re: Volcano Ash cloud

Post by brendo » Tue Jun 14, 2011 8:03 pm

wouldlove to know the amount of gases being spewed into the atmosphere and a comparison of it to the emissions our country produces. really negates any pitiful reductions tryin to be made. maybe if chile had a carbon tax on volcanoes this wouldnt be happening :idea: :lol:

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