bigbud
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Posts: 180
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Post by bigbud on Nov 13, 2012 11:16:54 GMT
Leif Acknowledging that we have an unusual development in sunspot activity in sunspot cycles 23-24, it must be very interesting to compare with the Dalton low and 1900-low, whether it is business as usual or something different this time (like Maunder) Unfortunately we dont have that many measurments for Maunder and Dalton. Geomagnetic records back to ~1850, and solar flux ~1950. So what other parameters can be used for comparison? I find this picture very interesting. Is it possible to evaluate the distribution of sunspot group size at the Dalton and 1900-low? Or are the data too poor?  ----------- I read from Ribes 1993 that the rotation rate in Maunder minimum was lower than normal. Do you know of any publication, page or downloadable database that shows rotation rate for each sunspot cycle? thank you for all your help  ------------ hmm, solar rotation seems more complex than I thought. There is sunspot rotation, global rotation, corona rotation and probably more... But what Ribes wrote about was rotation rate from sunspots, and it was lower at the Maunder than modern. Also I read that big sunspots rotate slower. So perhaps (simply) the Maunder sunspots were actually bigger, but less visible? If you have time, please enlighten me JAn |
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Post by lsvalgaard on Nov 15, 2012 0:43:10 GMT
Leif Or are the data too poor? -JAn We simply do not have the early data broken out into sizes or types in any convenient way [some work could be done, but hasn't been] One paper I co-authored: www.leif.org/research/ast10867.pdfsuggests that high solar activity slows down the Sun. |
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Post by justsomeguy on Nov 15, 2012 7:36:41 GMT
Wow, that is extremely interesting. Kinda mind blowing even. I guess the invariate sun model can now just be tossed away...
Is there any effect on TSI or other output parameters from the same mechanism that causes the velocity changes in different regions of the sun? Does this velocity change you describe account for the changes we are currently seeing in the internal "conveyer belt" within the sun?
From the conclusion in this very interesting paper:
"A secular deceleration of the mean solar rotation in the 20th
century was found by tracing sunspot groups. This variation
also shows a finer modulation indicating a connection
with the phase of the 11-year solar cycle. In the years 1902
and 1913 we have found possible rotational signatures of
two weak solar activity cycles (Gleissberg minimum). The
rotation velocity residual increased in these years for about
0.4 ◦/day. This is in a qualitative and quantitative agreement
with a similar rotational behaviour during the Maunderminimum.
A qualitatively similar behaviour was also found on
a shorter time scale for the period 1998–2000. As solar activity
was increasing, the equatorial rotation velocity determined
tracing coronal bright points was decreasing (in this
part of analysis monthly values were used)."
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bigbud
Level 3 Rank
Posts: 180
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Post by bigbud on Nov 15, 2012 8:44:11 GMT
thank you Leif A question: I find some reports saying that the rotation rate has increased the last century (like Li 2011, Heristchi 2009), but they dont measure differential rotation of sunspots, but rather the solar activity rotation rate using sunspotnumber or flux, and wavelet or fourier spectra. So are they measuring something else? Could we compare this with volcano hotspots on Earth, where volcanoes emerge and drift away? And at the Sun we have active longitudes that produce sunspots? So the rotation of active longitudes on the Sun is actually going faster? While the sunspots that are "ejected at the hotspot" drift away slower? So perhaps the interior has been accelerating, and the surface is slowing? Or is this a wrong speculation? Why do some find acceleration, while the publication you referred to showed deceleration? |
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Post by zots01 on Nov 18, 2012 11:51:54 GMT
Dear bigbud and dr Svalgaard I have also an observation about rotation/active longitude: following this famous link satdat.ngdc.noaa.gov/sxi/archive/browse/special/sxi_g15_cs_latest_27days.mpgit seems to me that the big black area, centered on north-east at the beginning, is lingering around the initial position. But it should rotate. After a while is swept away by the coming bright points and areas. But soon I can see it reappearing in the same area, as the sun where not rotating there. Can anybody confirm me that? |
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Post by france on Nov 20, 2012 15:39:22 GMT
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bigbud
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Posts: 180
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Post by bigbud on Nov 20, 2012 22:36:02 GMT
france at first sight very impressive, but after reading it... he has only made a good point on the obvious 11,86 year cycle. The two other ones of 9,93 and 11,08 years are more difficult to explain. He has found some similar cycles of 11,08 years, but not any real/good explaination why they influence the Sun. And the 11-year cycle must be a very powerful one, since no known cycle has breached it. Nor has he a good explaination of the 10 year cycle. This is also a very powerful cycle, and the small tide produced by Saturn cannot be the driver. So in my opinion, the 10 and 11 year cycles are still unknown. My own work has taken another turn. I dont think the ~11 year cycle comes from Venus+Earth+Jupiter syzygies. I have studied the tides, and they are simply not strong enough (compared to the other tides). So I am now exploring whether it may be some kind of internal cycle/dynamo property. And the 10-year cycle is obviously related to Jupiter+Saturn, but in what way? it is not tides. And I seem to get "good correlations" without help from any Uranus+Neptun... so that puts the barycenter-hypothesis under pressure. |
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Post by justsomeguy on Nov 25, 2012 15:41:47 GMT
I think this is all bunk and it is based on the solar dynamo. The planets are way too far out to have any effect on the solar cycle.
Can you guys predict something so we can prove you wrong? or right?
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bigbud
Level 3 Rank
Posts: 180
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Post by bigbud on Nov 25, 2012 15:48:24 GMT
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Post by richardh on Nov 25, 2012 19:27:59 GMT
Dr S. The F10.7 graphic shows a "ringing" for the last 6 months. Is this significant?
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Post by lsvalgaard on Nov 26, 2012 10:04:56 GMT
Dr S. The F10.7 graphic shows a "ringing" for the last 6 months. Is this significant? all solar indices show strong rotational modulation right now. This is not unusual. |
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Post by karlox on Dec 12, 2012 19:03:36 GMT
Dr. Isvalgaard, please take a look at following article (sorry for it is in Spanish) . It comments on new scientific support for the idea that planets could influence sun´s magnetic activity through cycles lasting for 88, 104, 150, 208, 506, 1000 or 2200 years. It refers to an article appeared in digital edition of Astronomy & Astrophysics. Results are from a multinational research team USA-SPAIN-SWITZERLAND and the article names J. A. Abreu and J. Beer del ETH from Zurich among others. Do you know about this? I find it most interesting... Please check and advise! Thanks! www.agenciasinc.es/Noticias/Los-p....gnetica-del-Sol |
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Post by lsvalgaard on Dec 13, 2012 14:31:07 GMT
Dr. Isvalgaard, please take a look at following article (sorry for it is in Spanish) . It comments on new scientific support for the idea that planets could influence sun´s magnetic activity through cycles lasting for 88, 104, 150, 208, 506, 1000 or 2200 years. It refers to an article appeared in digital edition of Astronomy & Astrophysics. Results are from a multinational research team USA-SPAIN-SWITZERLAND and the article names J. A. Abreu and J. Beer del ETH from Zurich among others. Do you know about this? I find it most interesting... Please check and advise! Thanks! www.agenciasinc.es/Noticias/Los-p....gnetica-del-Sol Yes, I know about it. I was a referee on an earlier version which was rejected by the journal it was submitted to. Apparently, the authors found a more friendly place to submit their paper to. I don't believe their result has merit, but it has appeal among many people. Here is some of my thoughts about that subject in general: www.leif.org/research/AGU%20Fall%202011%20SH34B-08.pdf |
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Post by karlox on Dec 13, 2012 16:15:50 GMT
Dr. Isvalgaard, please take a look at following article (sorry for it is in Spanish) . It comments on new scientific support for the idea that planets could influence sun´s magnetic activity through cycles lasting for 88, 104, 150, 208, 506, 1000 or 2200 years. It refers to an article appeared in digital edition of Astronomy & Astrophysics. Results are from a multinational research team USA-SPAIN-SWITZERLAND and the article names J. A. Abreu and J. Beer del ETH from Zurich among others. Do you know about this? I find it most interesting... Please check and advise! Thanks! www.agenciasinc.es/Noticias/Los-p....gnetica-del-Sol Yes, I know about it. I was a referee on an earlier version which was rejected by the journal it was submitted to. Apparently, the authors found a more friendly place to submit their paper to. I don't believe their result has merit, but it has appeal among many people. Here is some of my thoughts about that subject in general: www.leif.org/research/AGU%20Fall%202011%20SH34B-08.pdf Thank you so much! well you´ve got the merit for creating school and for keep on questioning ritht questions and getting new answers for the better understanding of our solar system. Thanks for that and please, keep us informed, you are doing a great divulgative task, which is highly appreciated by many. Thank you! |
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Post by Doug Huffman on Dec 24, 2012 12:57:09 GMT
Merry Christmas, Dr. Leif, God Jul
We are near SC-24 Maximum, but maximum what? All the time series data, with which I am familiar, seem near the low end of their ranges. Is there a datum that is near its maximum, perhaps some proxy for solar irradiation?
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