Record amount of small sunspots?

[Patrick P.A. Geryl]

Has anybody an idea if we have now a record amount of small sunspots since the measurements started?

Meaning 5 sunspots that give around 135?

And when was the previous high?

[Jesterface23]

If you are going off of Solen information, you'd be the best one here to know. Still, they wouldn't even have a complete cycle of high res data yet.

I only see region 3311 going up to a sunspot number count of 43.

[Philalethes]

2 hours ago, Patrick P.A. Geryl said:

Has anybody an idea if we have now a record amount of small sunspots since the measurements started?

Meaning 5 sunspots that give around 135?

And when was the previous high?

This is a great question, but I think it's really asking two separate questions; one about individual sunspot area, and the other about the number of sunspots per active region.

I might try to use individual sunspot data later for the first question, but as a rough approximation for the second question I decided to use the group data from this site (I had a hard time finding any other historical record containing the number of active regions at any given point in time, let me know if you or anyone else knows any) to do a simple check of the ratio between the SILSO daily sunspot number and the number of active regions in the aforementioned data. It's obviously not going to be perfect, but it should give some idea; if the ratio is high (many sunspots, few active regions) you'd expect that there are more small sunspots and vice versa (although it might not always be the case, since even a single large AR can contain many large spots too, I might check and compare that later either using the same site or a different one if I find better data for individual sunspot area).

That data only goes up to 2018, so I'll only be providing values within the time period from about 100 years before that until that point (earlier data is likely less reliable). I'm only counting groups where the corrected value for umbral area is greater than 0, so as to not include lots of inactive groups, and also only SILSO days with a SN greater than 0 (but I can't imagine the SN being 0 and there being any group with any umbral area anyway, although I didn't specifically check for something that weird).

For reference, if we use the numbers you provided of 5 ARs and an SN of 135, that ratio is 135 / 5 = 27.

So, first of all here I've used "5-year" smoothing, although since not all days actually have regions or sunspots it's not really 5 years, but it still serves to provide an average over the equivalent amount of days that actually have measurements, just so that we can see the general curve of the ratio:

What we can glean from this is that we're actually at relative lows when it comes to this ratio (or at least we were until around a decade ago). In other words, there is now generally a low number of sunspots per active region. That being said, the value provided for today of 27 is higher than this average, so that does indicate that there are more sunspots per active region. This is the only smoothed view I'll provide, next are some periods where I've zoomed in on the actual ratios without any smoothing to see how they compare; first off is a few years from around 2015 to the latest values in 2018:

Here we can see that values of 27 and above is reached regularly, so it's unlikely that today itself is anything special in that regard. Some of the values here are above 50, nearly double, so it's definitely no record in terms of that. Here's only the last year of the data:

Here the 27 of today would have represented one of the smaller peaks, but still wouldn't be record-breaking.

Here's the period 1957-1959, famous for its extreme levels of activity:

Interestingly, the ratio still hovers around 15-30 for the most part, with some dips a bit below that and some peaks a bit more above that; so clearly this ratio doesn't give the entire picture at all, since you can have tons of activity even with the same ratio as today. If I get around to looking into individual sunspot area later it'll be interesting to see how various time periods compare in that regard too. Here's the succeeding period of lower activity in the 1960s:

As you can tell from the first plot of the smoothed ratios that's one of the periods with the highest ratios in that regard, and here we see values from 40-70 regularly, and even 80-100 sometimes; that's a lot of sunspots per AR, and it's hard to envision how that's possible without a lot of small sunspots, especially during periods of lower activity. But again it should certainly be cross-referenced with individual sunspot area data.

Based on just this brief look I would guess that we might currently be at a local peak in that value, but that it's not anything record-breaking at all.

[Patrick P.A. Geryl]

I can’t find many small sunspots in 2017/08, nor in 2015/12….

I don’t mean the Solen ones, but the official ones.

Edited May 24, 2023 by Patrick P.A. Geryl

[3gMike]

38 minutes ago, Patrick P.A. Geryl said:

I can’t find many small sunspots in 2017/08, nor in 2015/12….

I don’t mean the Solen ones, but the official ones.

What is the significance of these two months?

[Philalethes]

14 minutes ago, Patrick P.A. Geryl said:

I can’t find many small sunspots in 2017/08, nor in 2015/12….

I don’t mean the Solen ones, but the official ones.

Those large spikes are essentially just a single or a few days. The spike in 2015 is 29/12, when SILSO lists 57 sunspots and the data I used only lists a single active region with any umbral area. In 2017 it's a period of 3 days from 17/08 to 19/08, where the SNs are 45, 45, and 50 respectively, all ascribed to a single area.

Looking around for days or time periods where there are more active regions (5 regions minimum, like today) and still a high ratio, I found e.g. this day in 2014; problem there is that as you can see it seems that ARs with no umbral area are included, and I don't really know how many of those SILSO include in their data (presumably not all of them, and that they're primarily in the image to show recently active regions too). But it still gives a decent impression, and as you can see there are quite a few small sunspots there. A bit further back there's this day, with the two days preceding it also being high in the plot above, where you can also see there are a lot of small sunspots.

But overall there aren't many prolonged periods in the recent few cycles where the ratio is consistently higher, since as you can tell from the first smoothed plot the ratio has been very low recently; to me it seems to indicate that when the ratio rises, there actually tends to be more activity, possibly because there are greater numbers of large sunspots too (still going to have to check individual sunspot group data on that). If you find imagery from further back (not available here on SWL), then you can check out some of these periods around 1979-1981, where there were seemingly a lot of days with more sunspots per AR than today (still filtered for minimum 5 ARs):

[3gMike]

6 hours ago, Patrick P.A. Geryl said:

Meaning 5 sunspots that give around 135?

How have you derived these numbers ? An indication of your source and any averaging would be helpful.

[Patrick P.A. Geryl]

2 uren geleden, 3gMike zei:

How have you derived these numbers ? An indication of your source and any averaging would be helpful.

This was early this morning. This website.

[3gMike]

29 minutes ago, Patrick P.A. Geryl said:

This was early this morning. This website.

Thanks, that is not what is currently shown and it does not match data stored in the archive for yesterday. In fact the data stored in the archive for yesterday shows the same number of spots (130) but a different number of ARs. I guess there may be some issues relating to when the website is updated. In any case it is difficult to come to any useful conclusion based on a single day's reading.

[3gMike]

7 hours ago, Philalethes said:

This is a great question, but I think it's really asking two separate questions; one about individual sunspot area, and the other about the number of sunspots per active region.

I just managed to pick up the latest photospheric field map from WSO and it allows an interesting comparison of the fields associated with ARs 3310 and 3311. Both ARs have similar field strengths and similar areas but activity levels are very different.

[Philalethes]

14 minutes ago, 3gMike said:

I just managed to pick up the latest photospheric field map from WSO and it allows an interesting comparison of the fields associated with ARs 3310 and 3311. Both ARs have similar field strengths and similar areas but activity levels are very different.

That's quite interesting, but I'm not sure if this is the right thread; perhaps you meant to post it in the thread where we've been discussing the flipping of the fields?

[3gMike]

1 hour ago, Philalethes said:

That's quite interesting, but I'm not sure if this is the right thread; perhaps you meant to post it in the thread where we've been discussing the flipping of the fields?

No, I meant to post it here. What I was attempting to show was that both these ARs have exceptionally large fields, covering at least 60 degrees of the disk - potentially allowing for development of a larger number of spots. But there is obviously more going on since AR3310 is much less active than AR3311.

[Philalethes]

27 minutes ago, 3gMike said:

What I was attempting to show was that both these ARs have exceptionally large fields, covering at least 60 degrees of the disk - potentially allowing for development of a larger number of spots.

Ah, I see; I didn't understand that that was the implication. Yes, maybe that has something to do with it, it would be interesting to dig up some old maps and compare them to similar regions in the past. Then again, ironically, 3110 is the diametric opposite, pretty much one huge spot (with only a few smaller ones appearing here and there).

Here's one from September 2014, around the time of one of the days I linked to above (this day): 

If I'm reading that correctly, the scattered region at the bottom (2172 and the spots to the right of it) is situated in the huge positive region at 240-300 of Carrington longitude above, isn't it? And the scattered region above (2175) would be the negative area above that one. That being said, a lot of these fields seem rather large to me, and I haven't looked at these maps enough to know what's exceptional or not; but that positive region above does at least look quite big.

Edited May 24, 2023 by Philalethes
autoformatting tries to make a smiley out of my parenthesis and colon

[3gMike]

22 hours ago, Philalethes said:

Ah, I see; I didn't understand that that was the implication. Yes, maybe that has something to do with it, it would be interesting to dig up some old maps and compare them to similar regions in the past. Then again, ironically, 3110 is the diametric opposite, pretty much one huge spot (with only a few smaller ones appearing here and there).

Here's one from September 2014, around the time of one of the days I linked to above (this day): 

If I'm reading that correctly, the scattered region at the bottom (2172 and the spots to the right of it) is situated in the huge positive region at 240-300 of Carrington longitude above, isn't it? And the scattered region above (2175) would be the negative area above that one. That being said, a lot of these fields seem rather large to me, and I haven't looked at these maps enough to know what's exceptional or not; but that positive region above does at least look quite big.

I would not claim to be particularly experienced as I have only been following the data since 2019 but I would suggest that the fields I identified are quite different to those you have identified for Rotation 2155. If you look at the contour lines for each of the fields associated with ARs 3310 and 3311 you will see that (apart from a small zone breaking away at the top of AR3311) the whole field is centred around one point, whereas if you look at the large positive field you mentioned at 240 - 300 longitude it has three separate centres, interacting with three separate negative fields spread across both hemispheres. So, although the positive field is large it results in three separate ARs sharing the energy from that field. That said, ARs 3310 and 3311 do not seem to be making great use of all the energy apparently available to them.

[Patrick P.A. Geryl]

Op 24/5/2023 om 15:29, Philalethes zei:

This is a great question, but I think it's really asking two separate questions; one about individual sunspot area, and the other about the number of sunspots per active region.

I might try to use individual sunspot data later for the first question, but as a rough approximation for the second question I decided to use the group data from this site (I had a hard time finding any other historical record containing the number of active regions at any given point in time, let me know if you or anyone else knows any) to do a simple check of the ratio between the SILSO daily sunspot number and the number of active regions in the aforementioned data. It's obviously not going to be perfect, but it should give some idea; if the ratio is high (many sunspots, few active regions) you'd expect that there are more small sunspots and vice versa (although it might not always be the case, since even a single large AR can contain many large spots too, I might check and compare that later either using the same site or a different one if I find better data for individual sunspot area).

That data only goes up to 2018, so I'll only be providing values within the time period from about 100 years before that until that point (earlier data is likely less reliable). I'm only counting groups where the corrected value for umbral area is greater than 0, so as to not include lots of inactive groups, and also only SILSO days with a SN greater than 0 (but I can't imagine the SN being 0 and there being any group with any umbral area anyway, although I didn't specifically check for something that weird).

For reference, if we use the numbers you provided of 5 ARs and an SN of 135, that ratio is 135 / 5 = 27.

So, first of all here I've used "5-year" smoothing, although since not all days actually have regions or sunspots it's not really 5 years, but it still serves to provide an average over the equivalent amount of days that actually have measurements, just so that we can see the general curve of the ratio:

What we can glean from this is that we're actually at relative lows when it comes to this ratio (or at least we were until around a decade ago). In other words, there is now generally a low number of sunspots per active region. That being said, the value provided for today of 27 is higher than this average, so that does indicate that there are more sunspots per active region. This is the only smoothed view I'll provide, next are some periods where I've zoomed in on the actual ratios without any smoothing to see how they compare; first off is a few years from around 2015 to the latest values in 2

Is it possible to put the average SSN above it till now? Just to see if there is a correlation with the high of the cycle…

[Philalethes]

46 minutes ago, Patrick P.A. Geryl said:

Is it possible to put the average SSN above it till now? Just to see if there is a correlation with the high of the cycle…

Well, like I mentioned the ratios above are mostly meant as a rough estimate over time, since smoothing when many dates are missing will cause distortions and displacement over time, especially the further back you go, so take it with a grain of salt; but here's a quick view of just the last cycles where the data is mostly intact, and it definitely looks like there is a clear relationship:

In other words, if this isn't just coincidence (and I doubt it is), it seems like the more sunspots there are in general, the more sunspots there are per group too. I don't think that's particularly surprising, it's definitely what I would expect to be the case. After all, from what I've seen, when there is more activity the regions tend to be larger and contain more spots.

I also see SILSO has a group number count up until 2010 that I had missed before, so it could be interesting to check against that too at some point. They have a monthly count, so you could always try to plot the monthly SSN against the monthly group number in the same way as here, that way you could perhaps see the correlation further back too.

Edited June 17, 2023 by Philalethes
typo

[Drax Spacex]

Perhaps related to this topic is the apparent paucity of active regions with delta magnetic configuration.  A non-delta region is likely correlated with a smaller number of sunspots per AR.  We have seen lots of ARs on the solar disk recently but not a delta since 2023-Jun-08.

 

 

[Philalethes]

9 hours ago, Drax Spacex said:

Perhaps related to this topic is the apparent paucity of active regions with delta magnetic configuration.  A non-delta region is likely correlated with a smaller number of sunspots per AR.  We have seen lots of ARs on the solar disk recently but not a delta since 2023-Jun-08.

Yeah, there could be a connection there, compared to the number of sunspots we've seen recently there's been a dearth of complexity indeed.

That being said I have seen some small deltas, e.g. 3340 had a small delta yesterday, but it disappeared quite fast.

I see now you mentioned that it got that designation in the other thread, but as far as I can tell it's already gone at this point.