Growth of Cycle 25

[hamateur 1953]

https://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0131.jpg        Thanks as always @3gMike  I was aware of his earlier prediction for this coming November being ssn max of course.   My feelings on northern hemisphere dominance  was a general impression based on recent activity.  The higher sfi vs ssn ratio this cycle is also interesting.   I actually would be very pleased if this was a temporary lull in overall activity, only to see a huge resurgence in both areas of ssn and solar flux.  Incoming regions in both hemispheres just might be just the thing I have been hoping for!   Time will tell.   Edit: added link to sdo 131.      For anyone else interested in viewing the huge cme launched on the limb, use the link above and use the 48 hour run.   Truly impressive explosion. 

Edited August 27, 2023 by hamateur 1953
Text& link.

[hamateur 1953]

As far as why we define solar maximum using sunspots alone?  History indeed. Although the interrelationships are for the most part unmistakable.   The TCI I have just begun to learn more about does seem to be a better indicator of our upper atmospheres response to solar irradiance.  Funny. I was pretty sure Id spotted a three month error in the 10/57 as being the hottest in the past based on 10.7 alone until Newbie suggested I review the A indices for earlier months!  There it was!   Lots of flaring.  So much for that!  At least I looked first.   Haha 

[tniickck]

summing up the results of August, current avg SSN is 101,9 (with 3 days left it should not really change)

3417 gives me hope for at least 1 good region since the middle of the August

Edited August 28, 2023 by tniickck

[3gMike]

2 hours ago, tniickck said:

summing up the results of August, current avg SSN is 101,9 (with 3 days left it should not really change)

3417 gives me hope for at least 1 good region since the middle of the August

Looking at the SILSO website https://www.sidc.be/SILSO/eisnplot it seems to be more like 117

[tniickck]

Just now, 3gMike said:

Looking at the SILSO website https://www.sidc.be/SILSO/eisnplot it seems to be more like 117

well, i calculated this myself, but we will see (the more the better, obviously) 

[hamateur 1953]

Well I hope for a resurgence in activity soon @Philalethesremarked that it has only been a month or so of decline in ssn and sfi.  At least we aren’t below sc 20 sfi at this point. ( if memory serves me).  Interesting was the remark made earlier by @libmar96on the number of M flares.  I agree it seems unusually high.  More like a typical downslope A index activity.  

[Philalethes]

24 minutes ago, hamateur 1953 said:

Well I hope for a resurgence in activity soon @Philalethesremarked that it has only been a month or so of decline in ssn and sfi.  At least we aren’t below sc 20 sfi at this point. ( if memory serves me).  Interesting was the remark made earlier by @libmar96on the number of M flares.  I agree it seems unusually high.  More like a typical downslope A index activity.  

Yeah, I was just referring to the SN (not the SSN, but I assume that's what you meant), not the SFI, but I would assume it has also gone down this month, at least the X-ray flux has been much lower most of the time I've looked at it. Also, if I'm not mistaken the SFI refers to the flux actually received here on Earth as reflected in e.g. the TCI, and is of course what hams are generally more interested in, but I would note that all the graphics I've provided are distance-adjusted flux, i.e. more of a measure of the Solar output, since I think that's more reflective of the cycle in terms of Solar activity.

As it currently looks SC25 continued to diverge from SC20 in terms of 365-day smoothing:

This is of course not necessarily reflective of the very latest activity, given the nature of the smoothing. If we just look at the past year or so for SC25 using 7-day smoothing for more detail, we can definitely see the drop that's occurred during the past month:

Still not possible to say if it really represents a peak or not if you ask me, as you see a similar drop in the 7-day smoothing earlier, from around month 35 to 36 above, where it drops ~50 points over roughly the same time period (even more precipitously at first, but with a rebound), which ended up being followed by a huge rise up to the largest peak so far; I think you can really only determine with certainty whether or not it's a peak after the fact.

[hamateur 1953]

I would definitely agree of course as to after the fact.   My memory is after all of cycle 20 like fifty years ago  that im pretty sure was using the Penticton CN  10.7 at the time.  They used to broadcast the A index and SFI daily on our US governments WWV regularly so us hams were kept well abreast of it. Also the A index although we hams paid little attention to these figures.  What do you think of the sfi vs ssn? Flux is nearly double the current numbers.  Definitely have never seen this situation before.. Of course we are only passive observers.  But it is interesting to me at least @Philalethes edit. Further complicating matters several sites rely on different ways of obtaining solar flux. I could list a few examples but we already are awash in data as it is!  I will stick with the Canucks for now.  They are pretty reliable.  They also have other adjusted flux available for those that require it btw. 

Edited August 29, 2023 by hamateur 1953
More flux

[Philalethes]

39 minutes ago, hamateur 1953 said:

What do you think of the sfi vs ssn? Flux is nearly double the current numbers.  Definitely have never seen this situation before.. Of course we are only passive observers.  But it is interesting to me at least @Philalethes edit. Further complicating matters several sites rely on different ways of obtaining solar flux. I could list a few examples but we already are awash in data as it is!  I will stick with the Canucks for now.  They are pretty reliable.  They also have other adjusted flux available for those that require it btw. 

Yeah, as has been discussed a bit in some other threads too the flux does seem higher than one would typically expect for the SN, although I assume that's just variance rather than some secular change, definitely an interesting development. Hard to say exactly how it manifests, perhaps more and smaller spots as I've seen suggested.

I'd definitely like to see other data sources for flux and know how it's obtained and how it differs from the NRCan data, I simply ended up using the latter because it was indeed quite reliable and dated a long time back, and since I saw it being used in a lot of places; it should yield a decent picture of the general development, and as far as I'm aware the recent data (last ~30 years and some) from Penticton is quite robust.

[3gMike]

5 hours ago, Philalethes said:

Still not possible to say if it really represents a peak or not if you ask me, as you see a similar drop in the 7-day smoothing earlier, from around month 35 to 36 above, where it drops ~50 points over roughly the same time period (even more precipitously at first, but with a rebound), which ended up being followed by a huge rise up to the largest peak so far; I think you can really only determine with certainty whether or not it's a peak after the fact.

I agree, but I have been attempting to make comparisons with previous cycles to see if we can draw any conclusions from what we have seen of cycle 25 to date. I chose to make the comparison using data from cycles 16 to 24, since cycle 16 was also a relatively low amplitude cycle, peaking at a SSN of 130. In order to allow an element of forecasting for cycle 25 I chose to use what might be considered -3dB points relative to Peak SSN to obtain three values....

Rise time from previous minimum to 3dB (70%) point, Time spent above 70% point and Time between rising 70% point and Peak SSN.

Rise time to 70% of Peak varied between 24 and 35 months from Minimum. We can exclude many of these values since we know that Cycle 25 reached a SSN of 113 in January 2023, meaning that the 70% point has to be greater than 80. Cycle 25 passed 86.7 in July 2022 (31 months after Min.) Given the current trajectory of SSN it seems unlikely that is the real 70% point, so I looked at values for 33 and 35 months, finding SSNs of 96.5 and 101 respectively. This would imply potential peak values of 136.5 or 143. Of course it is possible that the 70% point may be later than any of the previous cycles but I consider this unlikely due to the current indications of falling SSN and 10.7cm flux.

Considering next the time spent above the 70% point in previous cycles we find a range from 38 to 51 months, with the average being 43 months. Time from rising 70% point to Peak SSN varied over a range  from 8 to 33 months, with the average being 20 months. On that basis, and assuming that SSN and 10.7cm flux do not continue to fall, it might be reasonable to forecast a Peak SSN in the range 136 to 143 around June 2024. Obviously this forecast does not come with a very high degree of confidence, but it does at least suggest that we have not passed peak just yet.

[hamateur 1953]

Thanks as always @3gMike  what I was hoping to hear.  Other things aside temporarily.  This should mean an increasing sfi over the next few months.  And a resumption of sunspot construction in general.   All else being relatively equal.  Historical behaviors really matter in predictions.   73. Mike/Hagrid   As an aside @KW2P has been very busy of late and got back to me.  I promised not to disclose the present SFI. As we both are well aware we probably need 200 or better this winter to make the 50mhz coast to coast F2 contact possible.  Double hop E is possible but unlikely.   

Edited August 30, 2023 by hamateur 1953
Contest

[hamateur 1953]

In response to @Philalethesquestion on sfi a bit ago. It appears that at least one site tracks sfi very close.  Too close imho because our atmosphere and F2 layers respond slower.  This can easily be seen when penticton posts like 380 sfi during an extended M flare for just one example.  Can really cause our wth? response to wonder if we were back in 1957 all over again.  Haha.  Why I and it seems Jan as well knows that flaring can skew results.  I don’t know how he adjusts for this, but have heard that he does. Penticton seems to revise on rare occasions such as these however.  Hopefully this helps.  Also Newbie watches sfi elsewhere which varies wildly btw. 
On the ssn/sfi ratio of double. I should have looked closer it seems… it has already happened in this cycle earlier. So much for my casual observations having correlations with hard data!! 🤣🤣🤣

Edited August 31, 2023 by hamateur 1953
Errata

[Drax Spacex]

On 8/2/2023 at 5:31 PM, Philalethes said:

Provisional SN for July is in: 159.1. Still quite impressive, and yet more evidence for SC25 being stronger than SC24, although that should be fairly obvious by now. This leaves the SSN for January at 113.3, only a few points below the SC24 high of 2014-04 at 116.4. This will be almost certainly be beaten next month, as even an SN of 100 for August will leave the SSN of February at 117.2, but by the looks of it we're seeing no sign of sunspot activity slowing down that much at all. To miss the SC24 maximum target the SN for August would have to drop down to 85, and even then it would have to stay there lest the target simply be hit in one of the subsequent months instead. Given how we're probably heading into maximum soon I don't really see that happening, but time will tell.

The results are in.  SC25 has officially surpassed SC24 in terms of 13-month smoothed sunspot number (SSN).  SC24 max SSN was 116.4.  As of September 1, 2023 the SC25 max SSN was 117.9.

Data Source: WDC-SILSO, Royal Observatory of Belgium, Brussels

 

[Philalethes]

11 minutes ago, Drax Spacex said:

The results are in.  SC25 has officially surpassed SC24 in terms of 13-month smoothed sunspot number (SSN).  SC24 max SSN was 116.4.  As of September 1, 2023 the SC25 max SSN was 117.9.

Data Source: WDC-SILSO, Royal Observatory of Belgium, Brussels

 

Yep; an uneventful month of low activity, but not quite low enough to avoid breaking that maximum!

[hamateur 1953]

Activity seems to have resumed again as we approach Solar Maximum.  We seem to be getting “ spurts” of it instead of a nice climb, but this just makes it more interesting.  I was on STAR yesterday reading the results of the latest meeting (SILSO I think and others).  They refigured max for Aug 2024 apparently. And stated that Scotts 180-190 monthly mean was what they called out as  his  I think, was looking less likely  on its being the closest in predicted  maximum.  Possibly correct, but we have eleven months for our sun to defy predictions and deliver it regardless.  Haha. Would sure be cool as far as SFI anyway……. 

[Patrick P.A. Geryl]

3 uren geleden, hamateur 1953 zei:

Activity seems to have resumed again as we approach Solar Maximum.  We seem to be getting “ spurts” of it instead of a nice climb, but this just makes it more interesting.  I was on STAR yesterday reading the results of the latest meeting (SILSO I think and others).  They refigured max for Aug 2024 apparently. And stated that Scotts 180-190 monthly mean was what they called out as  his  I think, was looking less likely  on its being the closest in predicted  maximum.  Possibly correct, but we have eleven months for our sun to defy predictions and deliver it regardless.  Haha. Would sure be cool as far as SFI anyway……. 

Which link are these results for the peak?

[hamateur 1953]

https://www.stce.be/    Apologies to all 

I was actually reading the first page of the above link where Scott and associates are being discussed. Not STAR as id unfortunately typed.  Sorry about this.  Yes check before you err!  I use both sites regularly as many others do Im sure.  Later. Mike/Hagrid 

[Philalethes]

10 hours ago, hamateur 1953 said:

Activity seems to have resumed again as we approach Solar Maximum.  We seem to be getting “ spurts” of it instead of a nice climb, but this just makes it more interesting.  I was on STAR yesterday reading the results of the latest meeting (SILSO I think and others).  They refigured max for Aug 2024 apparently. And stated that Scotts 180-190 monthly mean was what they called out as  his  I think, was looking less likely  on its being the closest in predicted  maximum.  Possibly correct, but we have eleven months for our sun to defy predictions and deliver it regardless.  Haha. Would sure be cool as far as SFI anyway……. 

From looking at the progression of previous cycles it doesn't seem that uncommon for activity to develop in that way, at least it seems like both SC21 and SC23 both steadily rose in such a "zig-zag" pattern, alternating between some months of high activity and some months much calmer.

And yeah, I would agree that the 180-190 SSN estimate is probably too high, but if I recall correctly those predictions in the papers that Scott published had quite wide margins; normally that'd be less impressive, but in this case I think it might still be one of the pre-cycle predictions that get close in terms of landing inside of the margins, given how most people were predicting such low values.

But of course we still can't know for sure where we'll end up yet, and I wouldn't mind blowing past the expected values either, heh. I do think landing at a peak of around 130-150 seems more likely at this point though. Time will tell!

[Archmonoth]

8 hours ago, Philalethes said:

And yeah, I would agree that the 180-190 SSN estimate is probably too high, but if I recall correctly those predictions in the papers that Scott published had quite wide margins; normally that'd be less impressive, but in this case I think it might still be one of the pre-cycle predictions that get close in terms of landing inside of the margins, given how most people were predicting such low values.

My guess is still +/- 5% of 180 or 170-190, to be equal or near SC23... this was based on the hypothesis/guess of the barycenter being reflective of the conservation of momentum which is expressed as turbulence/flares. 

[hamateur 1953]

That’s exactly what I am hoping for as well.  It would take a steeper  continuous climb presently, given the presently intermittent climb. But it is conceivable and may happen.  

 

4 hours ago, Archmonoth said:

My guess is still +/- 5% of 180 or 170-190, to be equal or near SC23... this was based on the hypothesis/guess of the barycenter being reflective of the conservation of momentum which is expressed as turbulence/flares. 

 

[Rubén Vázquez]

Good morning from Spain. It seems that activity has increased in September, but it does not seem like a rapid escalation. What do people with more experience think? A hug and thank you. 

 

[hamateur 1953]

https://www.stce.be/content/sc25-tracking         We have all been watching this closely of course.  For myself, primarily Solar Radio Flux at 10.7.  I haven’t been following the overall activity levels as much as far as flares or CMEs but the Belgian guys have. I will post a link to their site on an edit here.  See above link. 

Edited October 2, 2023 by hamateur 1953
Added link

[3gMike]

4 hours ago, Rubén Vázquez said:

Good morning from Spain. It seems that activity has increased in September, but it does not seem like a rapid escalation. What do people with more experience think? A hug and thank you. 

 

I would agree with you. Solar flux and Sunspot numbers have grown a little during September, but they were starting from a very low level at the end of August. To give it some more context you can view levels for the last 12 months on the Solen website https://www.solen.info/solar/. It is not easy to predict if we will see another growth spurt, as indicated by the dot-dash line, or if it will flatten out as indicated by the dashed line on the plot you posted.

[Rubén Vázquez]

Thank you very much for your responses. It seems that the trend is towards a clear decrease in activity at the moment.

 

Edited October 20, 2023 by Rubén Vázquez

[hamateur 1953]

Yes, it is indeed.   Across the board. Solar radio flux is down, sunspot numbers have plummeted.  However I remain optimistic that we haven’t seen the last of SC 25 as far as fireworks and higher SFI.  By next January we will have a better idea of how this one will play out.  As always, time will tell. 
respectfully, Mike/Hagrid