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Relationship of polar field strength to sunspot hemispheric frequency


hamateur 1953
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It took me a while to even phrase that question properly!! . I will use the present cycle as an example. Since it appears to me anyway that for at least the last six months or so the northern hemisphere has been dominant. And I have read several observations that it reversed last April 2023. And it appears that the southern pole is about to follow suit, should we begin to see more active regions in general in the Southern Hemisphere after this occurs? For some reason this seems to make sense to me, although I havent read this yet as far as I can recall. Any ideas? Im unconcerned with average latitudes, just perhaps a greater frequency of ARs in S Hemisphere. Thanks! Mike/ Hagrid.

Edited by hamateur 1953
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1 hour ago, hamateur 1953 said:

It took me a while to even phrase that question properly!! . I will use the present cycle as an example. Since it appears to me anyway that for at least the last six months or so the northern hemisphere has been dominant. And I have read several observations that it reversed last April 2023. And it appears that the southern pole is about to follow suit, should we begin to see more active regions in general in the Southern Hemisphere after this occurs? For some reason this seems to make sense to me, although I havent read this yet as far as I can recall. Any ideas? Im unconcerned with average latitudes, just perhaps a greater frequency of ARs in S Hemisphere. Thanks! Mike/ Hagrid.

It is fairly well illustrated in this plot from Jan Alvestad's websitecycle24.png

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Thanks Mike, you know I have probably seen this before. It makes sense. I was reading a summary and prediction on Jan Alvestads site giving a pretty large window of solar max occurring between this Oct and 2025. Similar to NASA I believe.

Another thing I have been meaning to look into to explain somethIng unusual in SC 20 which had a small peak if you can even call it a peak In April of 1968 I think it was and was smoothed nearly flat for two years afterwards approximately. Very unusual. And was imagining active regions nearly opposite each other continually on the sun so that the hemispheres may have been in phase as far as activity but not physical locations. What do you think? Seems unlikely. I dont know if that type of observation would have been done even. So long ago. Haha.

Edited by hamateur 1953
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On 12/6/2023 at 5:20 PM, hamateur 1953 said:

Thanks Mike, you know I have probably seen this before. It makes sense. I was reading a summary and prediction on Jan Alvestads site giving a pretty large window of solar max occurring between this Oct and 2025. Similar to NASA I believe.

Another thing I have been meaning to look into to explain somethIng unusual in SC 20 which had a small peak if you can even call it a peak In April of 1968 I think it was and was smoothed nearly flat for two years afterwards approximately. Very unusual. And was imagining active regions nearly opposite each other continually on the sun so that the hemispheres may have been in phase as far as activity but not physical locations. What do you think? Seems unlikely. I dont know if that type of observation would have been done even. So long ago. Haha.

David Hathaway has produced a very good article discussing many aspects of solar activityhttps://link.springer.com/article/10.1007/lrsp-2015-4#Fig26

In terms of hemispheric asymmetry it is worth reading section 4.11

Edited by 3gMike
Corrected section reference
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1 hour ago, 3gMike said:

David Hathaway has produced a very good article discussing many aspects of solar activityhttps://link.springer.com/article/10.1007/lrsp-2015-4#Fig26

In terms of hemispheric asymmetry it is worth reading section 4.11

Did you intend to link directly to section 4.11? If so I believe this would be the right link, but maybe I misunderstood and that that was just a mention afterwards.

In any case, great article, densely packed with lots of interesting information.

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48 minutes ago, Philalethes said:

Did you intend to link directly to section 4.11? If so I believe this would be the right link, but maybe I misunderstood and that that was just a mention afterwards.

In any case, great article, densely packed with lots of interesting information.

I intended to link to the whole article and referred the section that seemed to be most relevant to the discussion. Another interesting section is 7.4 - Predicting cycle amplitude based on polar fields.

I seem to recall that at one time we had a thread providing links to useful documents. I might see if I can find it and add this one as it seems to be very comprehensive and includes a number of links to other work.

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16 minutes ago, 3gMike said:

I intended to link to the whole article and referred the section that seemed to be most relevant to the discussion. Another interesting section is 7.4 - Predicting cycle amplitude based on polar fields.

I seem to recall that at one time we had a thread providing links to useful documents. I might see if I can find it and add this one as it seems to be very comprehensive and includes a number of links to other work.

Ah, I see; I thought since it linked to a specific figure that it was intentional and got mixed up, but I guess that just got tacked on there.

And yeah, I remember that thread, this article definitely belongs there, it should be quite informative for both people who already know a lot about it as well as beginners (although perhaps a bit dense for the latter, but from skimming it it seems like it breaks things down very well).

14 minutes ago, hamateur 1953 said:

M flare just now looks like from D-RAP.

Guess it was the C8, unless you've unlocked future sight.

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20 hours ago, 3gMike said:

David Hathaway has produced a very good article discussing many aspects of solar activityhttps://link.springer.com/article/10.1007/lrsp-2015-4#Fig26

In terms of hemispheric asymmetry it is worth reading section 4.11

Comprehensive would be an understatement . And I downloaded the entire PDF for future reference. Interesting also that they may reevaluate the maunder minimum spot counts. I only pray they dont pick a new frequency other than 10.7 until I am off of this planet. Haha. Tnx again guys. Mike. Edit: Just one item in there I might take issue with and that was the statement that inferred SC 19 had a double peak. First time I have seen that statement. Hmmm. Gonna reread it later perhaps. Edit: yup there is indeed a double peak, however SC 19 was such an extreme cycle it happened two months apart!!

Edited by hamateur 1953
Cycle 19 double peak ???!! Or one 27 day rotation?
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16 minutes ago, hamateur 1953 said:

I only pray they dont pick a new frequency other than 10.7 until I am off of this planet.

I doubt they're going to stop measuring that anytime soon. Even if certain other candidates have potential to be marginally better, like e.g. F30, I bet they'll just measure those alongside F10.7 for a long time, at least that's what they've done with F30 specifically. Maybe after long enough periods of measuring both (and other frequencies) they'd replace it as the "standard" if they found another to be noticeably better, but even then they probably wouldn't stop measuring F10.7 for a while anyway, at least not until the head start it has in terms of historical records due to being the first becomes negligible. Then again, maybe we won't even ever stop measuring it as long as we remain a technological civilization given how it'll likely just get easier and easier to do.

I'd say you're safe for at least a few centuries.

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14 hours ago, Philalethes said:

I doubt they're going to stop measuring that anytime soon. Even if certain other candidates have potential to be marginally better, like e.g. F30, I bet they'll just measure those alongside F10.7 for a long time, at least that's what they've done with F30 specifically. Maybe after long enough periods of measuring both (and other frequencies) they'd replace it as the "standard" if they found another to be noticeably better, but even then they probably wouldn't stop measuring F10.7 for a while anyway, at least not until the head start it has in terms of historical records due to being the first becomes negligible. Then again, maybe we won't even ever stop measuring it as long as we remain a technological civilization given how it'll likely just get easier and easier to do.

I'd say you're safe for at least a few centuries.

I reviewed Jan Alvestads charts for SC 19. 1957-58. There is indeed a double peak. Nearly identical peaks about two months apart. Not visible in the renderings of that cycle naturally as smoothed values have been and are used when SCs are depicted typically.
380 sfi and 350 sfi. Id settle for either as a maximum. Hahaha. Mike.

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