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Fledermaus
2008-Mar-29, 11:49 AM
Hi,
When I have been on tour on my Motorbike up in Scottyland (Scotland to the norm) I fell for the Northern Lights and have made around 8 trips to see them. The last time I went the lights were not so colourful but lasted longer, I was concerned that the thining of the ozone may be affecting them? I know that weather fronts and air moisture does affect them as my mad weather friend I see every time I land in Scottyland tells me and he helps me plan the trips there letting me know when the weather is near enough at its best to see the best of the lights as he lives there. He doesnt know whats happening either and has asked me to let him know if I get any info, and ideas?
(Fledermaus)Karin:think:

neilzero
2008-Mar-29, 01:03 PM
I presume ozone has a small role in the Northern lights, but my guess is you should not conclude the lights are becoming less colorful, based on a sample of one out of eight, or even a recent ten out of 80 that your Scottyland friend may have observed. Too small a sample to rule out coincidence. Neil

grant hutchison
2008-Mar-29, 03:05 PM
The weather doesn't affect the aurora borealis, except by blocking the view from ground level when it's cloudy or hazy.
Auroral activity follows the solar cycle, and also fluctuates from day to day, hour to hour and minute to minute, so there are lots of other possible explanations for your observations. We've been on the downslope of solar cycle 23 since about 2002, for instance, and are probably just starting the upstroke of cycle 24. So if all your trips have been in the last six or eight years, you're probably just seeing the natural cycling of auroral intensity.
Most of the auroral light comes from the ionization of neutral oxygen atoms in the high atmosphere, with a contribution from molecular oxygen and molecular nitrogen. Ozone is such a minor component of the atmosphere that its contribution will necessarily be slight.

Grant Hutchison

Fledermaus
2008-Apr-02, 08:17 PM
Thank you Grant, for clearing that up for me! But I dont know what the solar up stroke cycles and down stroke cycles are! I shall try to find out, but would be happy if could explain them briefly if its possible?

grant hutchison
2008-Apr-02, 08:34 PM
Thank you Grant, for clearing that up for me! But I dont know what the solar up stroke cycles and down stroke cycles are! I shall try to find out, but would be happy if could explain them briefly if its possible?There's a natural, eleven-year cycle of sunspot activity. Sunspots are associated with active regions on the sun's surface, which emit charged particles into space. When these charged particles hit the Earth's magnetic field, they are deflected north and south, and then funnelled down around the geomagnetic poles. When the particles hit the high atmosphere (in a ring around the geomagnetic poles called the "auroral oval"), we see the auroras.
So auroral activity is driven by sunspot activity in an eleven-year cycle.

We've seen steadily decreasing activity, as part of this cycle, since 2002. That's what I was calling the "downstroke" of the cycle. We're due to see renewed, rising activity, which is what I called the "upstroke".

Grant Hutchison

Fledermaus
2008-Apr-05, 07:45 AM
Cheers Grant!!
That has made things much clearer, its obvious I have a lot more to learn about the aurora borealis! I should stop presueing my love of the moon and look more into the northern lights!

Casus_belli
2008-Apr-05, 01:58 PM
Im lucky enough to live a hundred yards from the Moray Firth so I get some un-paralleled views of Aurora.

I doubt I have ever seen two displays that were similar. Its all to do with the intensity of the solar storm. The different colours are down to what atoms are being excited Green and reds are oxygen and Nitrogen produces dark reds and blue/violet displays. (According to wikipedia anyway)

During the last solar Maximum displays were common but never boring. It has been quiet recently but I've already seen 3 displays this year.

korjik
2008-Apr-05, 04:54 PM
reds are hydrogen

Aurora are caused by electron precipitation during a magnetic substorm. In really simple terms, a blob of solar wind bangs on the Earth's magnetic field and knocks loose a bunch of fairly energetic electrons. The electrons stream down the magnetic field lines until the atmosphere starts getting too thick, and the electrons start colliding with neutral atoms. Some atoms are ionized and some are just excited, and the glow comes when the atoms go back to their original state (ground state). The color of the glows are determined by the specific atom exited.

I think all of this is well above the ozone layer, but I would have to check to be sure. Plus, if it were at the ozone layer, ozone is all oxygen, so it wouldnt make a difference to the color if the oxygen were ozone (O3) or molecular oxygen (O2)

grant hutchison
2008-Apr-05, 05:13 PM
reds are hydrogenAlthough hydrogen produces a red emission, the gas is so rare it contributes very little light to the aurora. Diffuse red auroras come from the 630nm and 636nm atomic oxygen lines. The red lower edges to the more common green auroral curtains are generated by molecular nitrogen bands.


I think all of this is well above the ozone layer, but I would have to check to be sure. Plus, if it were at the ozone layer, ozone is all oxygen, so it wouldnt make a difference to the color if the oxygen were ozone (O3) or molecular oxygen (O2)Molecules have different emission bands from atoms, which vary according to the molecular structure, so it might make a difference.

Grant Hutchison

korjik
2008-Apr-06, 07:59 AM
Although hydrogen produces a red emission, the gas is so rare it contributes very little light to the aurora. Diffuse red auroras come from the 630nm and 636nm atomic oxygen lines. The red lower edges to the more common green auroral curtains are generated by molecular nitrogen bands.

I was thinking nebula, now that you mention it.


Molecules have different emission bands from atoms, which vary according to the molecular structure, so it might make a difference.

Grant Hutchison

ozone is unstable enough that I imagine it would be hard to get much molecular radiation without breaking up the molecule.

Fledermaus
2008-Apr-08, 07:31 AM
[Im lucky enough to live a hundred yards from the Moray Firth so I get some un-paralleled views of Aurora.

I doubt I have ever seen two displays that were similar. Its all to do with the intensity of the solar storm. The different colours are down to what atoms are being excited Green and reds are oxygen and Nitrogen produces dark reds and blue/violet displays. (According to wikipedia anyway)

During the last solar Maximum displays were common but never boring. It has been quiet recently but I've already seen 3 displays this year.]

You are so lucky to live there, I have toured Inverness,to Duncansby Head and I go higher to see the Aurora but its long haul for me on my own, but I am adicted to them. I was just unsure if the ozone affected the Auroras and had to ask. I know the chemistry side or I thought I did, my knowledge is becomeing a bit more refined thanks to everyone who is joining the thread and its great!Keep going :)

mugaliens
2008-Apr-08, 02:21 PM
Good answers, Grant!

Despite having lived in some northern latitudes, I've never actually seen the northern lights.

One day I'd like to!

Eroica
2008-Apr-11, 03:03 PM
Aurorae are normally found at altitudes between 100-400 km.

The Earth's ozone is concentrated in a narrow band at an altitude of about 15-30 km. I don't see how ozone could have any relevance to auroral activity.