Growth of Cycle 25

[hamateur 1953]

53 minutes ago, willow said:

The daily sunspots number is really impressive right now! has been actively growing, reaching 300 today!

We Hams are all hoping for a recurrence in about two weeks of this resurgence from the recent depths of sn and SFI.   Both are likely to drop next week unless more longitudes become active.  Then we see what we see. 

Edited April 22 by hamateur 1953

[Philalethes]

I made a couple of visualizations of the Carrington longitude data I mentioned previously. It's not counting the area exactly at each longitude, just assigning the area to the longitude assigned to the region, but if there are certain longitudes with persistently more activity than others it should be possible to make out. From looking at it it's not that clear, but it does seem like there is some persistence, and possibly a bit of drifting, which would make sense, but I think more in-depth statistical analysis would be in order to establish that.

It's been binned into a 2D histogram where each time step is a Carrington rotation and each longitude step is 2° in width (although there are many possibilities of varying these that lead to different results, if anyone is curious about what some particular bin size would look like), and the value of each bin is the total accumulated active area counted once each day (so if e.g. a region persists for 5 days within a single rotation, its area is counted each day). The result is essentially a Hovmöller diagram, like what Scott uses to show the development of EUV brightpoints (BPs) over time.

Here's one for the entire regular series, from 2010:

And one for SC25 only, using the NRT data so it's as up-to-date as possible:

From inspecting it visually I would say there does seem to be certain longitudes that are a bit more active than others (like e.g. around 90°-120°), with a certain diagonal drift towards the right (which can also be seen in the gaps), although it's hard to say whether that's actually statistically significant or whether it's just a form of clustering illusion, hence why more analysis would probably be in order for that. Would probably be best to place the active area with a bit more resolution than just all with each group at a time too, and maybe also account for different latitudes with separate plots.

[hamateur 1953]

Interesting @Philalethes  now I think

that it is worth digging up that old discussion.  I cannot imagine what physical processes would cause clustering near any longitude in any cycle but a sample size as large as you have chosen should reveal it.  What would be hilarious is if it ultimately turned out to be that weird Dogbone asteroid Kleopatra’s orbit…. Haha  Found it. 
It pertained to a discussion between you @Philalethes and @Drax Spacex regarding a 30 day periodicity in polar field variations.  If you recall the discussion, Mike. 

Edited April 22 by hamateur 1953
Doggone it

[Philalethes]

22 minutes ago, hamateur 1953 said:

 I cannot imagine what physical processes would cause clustering near any longitude in any cycle but a sample size as large as you have chosen should reveal it.

Well, I'd definitely be careful about making statements about what the data "should" reveal, heh; I do it myself of course, but with clear caveats that there are tons of pitfalls in this type of data analysis, and it could be that other methods would much more clearly reveal whether or not such more active longitudes do or do not exist in any statistically significant way.

As for the physical processes that could be responsible, I don't have a too hard time imagining some general possibilities, since areas where strong opposite fields are being mashed together do seem to persist across Carrington rotations in many cases (but sometimes they change drastically too). That's not to claim an understanding of the actual kinetics and magnetohydrodynamics involved that give rise to the complexity, which are mind-bogglingly complex, but more to say that I can see how those underlying processes could potentially persist in a given location of the surface for a while, possibly while drifting a bit.

You could of course also leave room for more speculative effects like planetary alignments and interstellar (or even intergalactic) fields and currents, but those I would indeed have a much harder time seeing leading to persistent activity at specific longitudes; if our entire star suddenly were to get supercharged by an inflow of a billion billion amps I think we'd be seeing a fair amount of activity across most longitudes, heh. Naturally, and needless to say at this point, I would want to see very clear and strong evidence of any such effects before accepting them as real.

37 minutes ago, hamateur 1953 said:

regarding a 30 day periodicity in polar field variations

Yeah, I remember discussing something like this, and there definitely does seem to be such a periodicity present in the data. If we e.g. look at some of the relatively recent polar field data (not the very latest), smoothing the data points across a day, we see it crop up very distinctly:

This oscillation is surely due to the fact that the polar field at various longitudes persists to some extent across rotations; it doesn't mean that each oscillation is exactly periodic though, since you'd get longer and shorter periods wherever there is a lot of movement in the field, like we see for some of the more irregular ones above, but as you can see in other places the oscillation is very stable and periodic. The overall period here seems to be around ~35 days, which happens to be more or less exactly what you'd expect for the average rotation rate at those latitudes.

That being said it doesn't mean that this automatically translates to regions of high activity persisting, but it's certainly a noteworthy observation given how activity is a result of what's going on with the underlying fields. We of course already know that certain very strong active regions can persist across multiple rotations. I do however suspect that once the fields have shifted sufficiently away from such configurations over the course of however many rotations, then there's no good reason to suspect they'll reform in those particular spots; in other words, that while there might be some persistence of active regions across multiple rotations, I strongly doubt you'd find anything like that for an entire cycle, the system is just too chaotic for that as far as I'm concerned. Now that I think of it, maybe that's what you meant originally, in which case I would agree that it's hard to envision any process that would keep a specific range of longitudes the most active throughout an entire cycle.

[hamateur 1953]

Yeah. Agreed. I wasn’t trying to infer anything by bringing it up really. Only illustrating that I recalled it being discussed. The field stuff is entirely new to me anyway as I probably have mentioned before.  This cycle will likely add more data to our understanding of the dynamics involved. I watched Scott’s presentation awhile back as you probably did.  It will be very interesting times for all of us over the next two years for certain!   Mike/ Hagrid   One last note: SFI at NRC close was 231 observed and 233 SFI adjusted flux.  Not a record quite yet, but edging closer. 

Edited April 23 by hamateur 1953
23:00 SFI

[Drax Spacex]

7 hours ago, Philalethes said:

I made a couple of visualizations of the Carrington longitude data I mentioned previously. It's not counting the area exactly at each longitude, just assigning the area to the longitude assigned to the region, but if there are certain longitudes with persistently more activity than others it should be possible to make out. From looking at it it's not that clear, but it does seem like there is some persistence, and possibly a bit of drifting, which would make sense, but I think more in-depth statistical analysis would be in order to establish that.

It's been binned into a 2D histogram where each time step is a Carrington rotation and each longitude step is 2° in width (although there are many possibilities of varying these that lead to different results, if anyone is curious about what some particular bin size would look like), and the value of each bin is the total accumulated active area counted once each day (so if e.g. a region persists for 5 days within a single rotation, its area is counted each day). The result is essentially a Hovmöller diagram, like what Scott uses to show the development of EUV brightpoints (BPs) over time.

Here's one for the entire regular series, from 2010:

And one for SC25 only, using the NRT data so it's as up-to-date as possible:

 

There is certainly information here using an interestingly different graphical presentation of solar cycle progression.  The long-term durability of some active regions across adjacent longitudes can be readily observed.  But as noted, no specific active longitudes for the entire solar cycle can be identified.

The curves and lines are apparent - possibly due to the latitude-dependent rotation rate of the Sun.  Persistent active regions may appear to drift across successive Carrington rotations when mapped to heliographic coordinates.  Most of these lines have a positive slope, indicating a drift to higher Carrington longitude values in successive rotations (perhaps because they are at less than 26° latitude and are therefore rotating faster?) 

From the 2010 full series image, solar minimum of December 2019 is apparent along Carrington rotation 2225.  What is interesting are the features several rotations before minimum.  We see a line with negative slope between longitudes 50-150, and a line with positive slope between longitudes 180-320.  Could this signify a transition that presages solar minimum?

7 hours ago, Philalethes said:

From inspecting it visually I would say there does seem to be certain longitudes that are a bit more active than others (like e.g. around 90°-120°), with a certain diagonal drift towards the right (which can also be seen in the gaps), although it's hard to say whether that's actually statistically significant or whether it's just a form of clustering illusion, hence why more analysis would probably be in order for that. Would probably be best to place the active area with a bit more resolution than just all with each group at a time too, and maybe also account for different latitudes with separate plots.

As for the clusters, yes some of that may be a matter of perception and not much different than what may result from a random distribution.  I wouldn't dismiss the possible persuasion of pareidolia, such as seeing a SSTV version of the Close Encounters mothership alien in the data:
https://ibb.co/LPRGMGD

[hamateur 1953]

5 hours ago, Drax Spacex said:

There is certainly information here using an interestingly different graphical presentation of solar cycle progression.  The long-term durability of some active regions across adjacent longitudes can be readily observed.  But as noted, no specific active longitudes for the entire solar cycle can be identified.

The curves and lines are apparent - possibly due to the latitude-dependent rotation rate of the Sun.  Persistent active regions may appear to drift across successive Carrington rotations when mapped to heliographic coordinates.  Most of these lines have a positive slope, indicating a drift to higher Carrington longitude values in successive rotations (perhaps because they are at less than 26° latitude and are therefore rotating faster?) 

From the 2010 full series image, solar minimum of December 2019 is apparent along Carrington rotation 2225.  What is interesting are the features several rotations before minimum.  We see a line with negative slope between longitudes 50-150, and a line with positive slope between longitudes 180-320.  Could this signify a transition that presages solar minimum?

As for the clusters, yes some of that may be a matter of perception and not much different than what may result from a random distribution.  I wouldn't dismiss the possible persuasion of pareidolia, such as seeing a SSTV version of the Close Encounters mothership alien in the data:
https://ibb.co/LPRGMGD

I couldn’t get the cool tones to play!  
was that a separate audio file?? Haha. 

[Philalethes]

6 hours ago, Drax Spacex said:

The curves and lines are apparent - possibly due to the latitude-dependent rotation rate of the Sun.  Persistent active regions may appear to drift across successive Carrington rotations when mapped to heliographic coordinates.  Most of these lines have a positive slope, indicating a drift to higher Carrington longitude values in successive rotations (perhaps because they are at less than 26° latitude and are therefore rotating faster?) 

It's certainly a possibility, or at least it might be one contributing factor. Most of the regions are indeed at the lower latitudes, with the the 10°-20° latitude range being the most populous. In some places it seems like regions occasionally drift in the other direction too though, so even if that's one of the factors I assume there are also others, like the fields themselves shifting and possibly also radial differential rotation around the near-surface shear layer.

One might expect to perhaps see signs of the difference by looking at the different latitudes, but from doing that it's still hard to see any clearly discernible pattern; here the plot is separated into two plots, with latitude ranges of 0°-20° and 20°-35° respectively:

Already in the second plot one can see regions becoming noticeably more scarce (from 35° and up there are very few). Some of the same active longitudes can be identified visually in the first plot, but whether there is more or less drift there is very tough to say.

On a different note, as mentioned briefly in passing it's also possible to look at the data using different parameters, like longer spans of time and narrower spans of longitude for the bins. For example:

Or even more extreme:

Whether or not these are any more useful (or useful at all) is another question, but we do see many of the same longitudes show up.

[Lawn Boy]

Jan’s latest update

Update on the progress of solar cycle 25 as of April 28, 2024

The big increase in sunspot counts during the April 14-27 interval caused a major uptick in the smoothed SNs and solar flux. It's not yet clear when the next peak will be, anytime between October 28 and December 20, 2023 looks possible. The 365d smoothed solar flux exceeded the June 27 peak on October 28, while the 365d smoothed ISN and NOAA SN both exceeded the June 2023 peak in late October 2023.

[hamateur 1953]

Given that the last sunspot count was well over 200 and solar flux and sunspot numbers caused Jan to set the chart maximum count to 300 from 250 I believe it was, in two weeks or less I hope for another similar, if not greater bump in running numbers, much like we saw six months ago, a gradual increase in peaks, giving higher smoothed averages or mean monthly counts.