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Ap & aa Indices and Solar Minimum

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It would seem so on that graph, indeed both IMF per the graph and Ap seem 'Rangebound' over the last year or so. A rough guestimation of Ap for this month would put it at 'around 5', (see if the chaps in Boulder agree with me). It will be an interesting indicator to see what happens in December - the negative swing of the R-M effect. Again on a rough guestimate based on current forecasts it looks like being 'around 4' - similar to 2008 - rather than the deep dives of 2009 onwards. If we then stay in the 4 to 7 range with light coronal hole activity and little in the way of spots for a prolonged period it could have some interesting connotations!

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8 hours ago, The Atmosphere Guy said:

If we then stay in the 4 to 7 range with light coronal hole activity and little in the way of spots for a prolonged period it could have some interesting connotations!

Do you care to elaborate on what are the possible connotations?  

The different indicators suggesting different outcomes, from this vantage point, already this far into the minimum, are a big enigma.

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It is, as you say, enigmatic. That the sun is not behaving in the manner to which we are accustomed is evident in all of the graphs. Whether this is due to external factors such as planetary clocking or to the internal mechanisms of the sun – or both, we can only guess and try to spot the clues.

We can see from the MSL chart that mesosphere temperatures are falling significantly; NLCs started unusually early this year, TC index is low and likely to continue lower. My favourite graph, the ‘Ap index’, seems to be ‘Flat-lining’ as do spots.

We know that the ‘Butterfly Gap’ was wider than average last time around, and looks like being wider still this time.

So what are the implications? If we see a sudden return to ‘normal’ then perhaps we carry on much as before. However if the ‘Flat-Line’ situation continues for a protracted period and struggles to rise we can assume that upper level temperatures will continue to decline and may struggle to achieve previous peak levels.

But what then of temperatures lower down. We know that the atmosphere contracts under cooling conditions. Stratospheric level thermal and pressure profiles contract towards the equator pulling polar structures with them.  The ‘Sea – Land Differential’ becomes the dominant influence on surface weather patterns which in turn tend to become rigidly stable – so the conditions you’ve got are what you keep, often for a long time, floods in some places, drought in others.

It’s an interesting thought experiment playing with the possibilities !

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14 hours ago, The Atmosphere Guy said:

If we see a sudden return to ‘normal’

What does one mean by a "return to 'normal'?  Consider that the sun is indeed in a state of 'normalcy', for where it is at, in this current age.  It very well could be that going forward, for some length of time (e.g., another one, two, or three cycles, at minimum), the new 'normal' for the sun is it typically manifesting fewer sunspots than what 'normal' was 30-40 years ago.  Nonetheless, that 'normal' still happens in conjunction with a release of solar wind, and the magnetic activity on the sun does not go into a complete state of dormancy.

14 hours ago, The Atmosphere Guy said:

we can only guess and try to spot the clues

Yes, clues are there.  

14 hours ago, The Atmosphere Guy said:

the sun is not behaving in the manner to which we are accustomed is evident in all of the graphs.

Even the enigmatic nature of clues suggesting conflicting outcome for the next cycle strength may itself be a 'clue', and prediction/forecasting will require a committed attention to sorting out what are the most important clues for activity forecasting.  

14 hours ago, The Atmosphere Guy said:

Whether this is due to external factors such as planetary clocking or to the internal mechanisms of the sun – or both

Absolutely, both are imprinted in the physical state of the sun/solar-system 'clock'.  

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6 hours ago, theartist said:

What does one mean by a "return to 'normal'?

My principle concern is the sudden anomalous drop in the 'Ap' chart that was noted at the start of this thread. That, coupled with the apparent 'wind down' evident from 2003, is I would suggest, unparalleled in our data. If that turns out to be a temporary aberration and we revert to something more representative of previous states I would consider that a "return to normal". If, as seems an alternative, that represents a 'step change' to a 'new normal' as you describe, and that continues for a protracted period, as I mentioned, then we may see significant changes at planetary level. Fascinating times !

Edited by The Atmosphere Guy
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According to the SORCE Total Solar Irradiance, (TSI, plotted below) the sun is actually 0.1 W/m^2 warmer than during the last solar minimum.

240453035_TSI11-21-09.thumb.png.0f09c61cb89222c789740957fe9a66ee.png

In consideration of the above graph (along with other signals discussed on this forum), I think today, at the end of November 2019, we are temporally similar to where we were in September 2008, and I've annotated the above graph to that effect.  The TSI will likely now stay in a range-bound period (of +/- 0.7 W/m^2, filtered) for several months, passing through the Solar Minimum Nadir to occur in ~Feb-Mar 2020, proceeding until a breakout, to possibly occur some 5 months later (i.e., ~Aug 2020).

Do you understand?  What do you think?

 

(Note, the Breakout from the range-bound period annotated in the above graph is relatively 'smallish', and is not what has been referred to as the cycle "Onset" which occurs later.  Further discussion on this is found in the thread titled,  "Synoptic Magnetograms; SC24 Minimum Forecasting".)

Edited by theartist

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Your thinking is much along the same lines as my own and is well supported by the data.

The potential for an extended minimum seems to show up in all of the data; the ‘Ap’ environment seems to be stuck in a ‘pre-minimum’ zone slightly above where one might expect it to have descended to, the ‘lighthouse’ CH structure going round like a stuck record. This seems to be supported by the TSI chart.

There is an interesting paper by Lisa Upton and David Hathaway; I quote from the summary:

“After the exceptionally weak Solar Cycle 24 (SC24), there is considerable interest in accurately predicting the amplitude of the coming Solar Cycle 25 (SC25). In 2016, the Advective Flux Transport (AFT) Model was used to make such a prediction. We now have two additional years of solar data. Here we compare the results of the previous prediction to the observations that have since occurred. We then use the additional two years of data to create an updated prediction, with a much smaller uncertainty. We predict that SC25 will be about slightly smaller (95%) (than) the strength of SC24, making it the weakest solar cycle in the last hundred years. We also predict that, like SC24, SC25 will be preceded by a long extended solar minimum. Finally, these results indicate that we are now in the midst of a Modern Gleissberg Minimum”.

The “...long extended solar minimum....” being particularly relevant.

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5 hours ago, The Atmosphere Guy said:

There is an interesting paper by Lisa Upton and David Hathaway; I quote from the summary:

I just read that paper a couple of days ago! 😄   I'm glad you have read it, because I want to make some comments on it.

The first and prime takeaway from that paper, was their comment that the polar field measurements "can be somewhat subjective".  That is a HUGE bullet-point, since a large body of the solar cycle prediction-science relies on a precursor technique based on the strength of the polar field.  As you probably know, Hathaway has been in the business of predicting solar cycles for at least two or three decades (though his predictions have not already panned out), so his assessment on that issue is pretty significant.

Edited by theartist

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5 hours ago, theartist said:

The first and prime takeaway from that paper, was their comment that the polar field measurements are subject to human subjectivity.  

That is what I read-into the following statement in the paper: "...while polar field measurements above a given latitude are useful for identifying hemispheric asymmetries, they can be somewhat subjective", from page 5 of the paper titled, "An Updated Solar Cycle 25 Prediction With AFT: The Modern Minimum" (source).

Edited by theartist

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On 11/29/2019 at 6:20 AM, The Atmosphere Guy said:

The potential for an extended minimum seems to show up in all of the data; the ‘Ap’ environment seems to be stuck in a ‘pre-minimum’ zone slightly above where one might expect it to have descended to, the ‘lighthouse’ CH structure going round like a stuck record. This seems to be supported by the TSI chart.

Along with a stuck Ap, we also now have the F10.7cm sitting at higher magnitude than during the last minimum's range-bound period.  Additionally, will the CH structure get cleared out before ascension into the next cycle, or are these factors, including the 'warmer' TSI this minimum, indicative of a 'seething sun', anxious to proceed upward from here?

Because of these enigmatic questions, I think we are at the stages of a critical pivot-point that will have implications for the strength of the next cycle.  Here are my current (ballpark) probabilities for the different scenarios:

  1. Scenario 1 is defined by the above annotated TSI graph and ensuing discussion, whereby Solar Minimum Nadir (SMN) is in Feb-Mar 2020 (give or take a month 🤪). 
    • Probability: 65%.
    • SC25 strength consequences: similar to SC24, or slightly weaker.
  2. Scenario 2 is one in which SMN is happening now, in the month of November, or before. 
    • Probability: 25%.
    • SC25 strength consequences: could be significantly stronger than SC24.
  3. Scenario 3 is one in which the SMN does not happen until sometime in 2021 (per the Upton&Hathaway paper cited above). 
    • Probability: 10%. 
    • SC25 strength consequences: Levels not seen in the last 200 years, as Kitiashvili said.

(Note, I realize Upton&Hathaway are forecasting SC25 strength levels to be only "slightly weaker than Cycle 24", but at this stage, I find their very late timeline of SMN's occurrence to be incongruent with that.  In order for SMN to happen over a year from now would suggest the sun is proceeding into radical low territory, in-line with Kitiashvili's forecast.)

Edited by theartist
Corrected spelling.

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On 8/28/2019 at 9:08 AM, The Atmosphere Guy said:

These are aspects that appear to be rarely, if ever, openly discussed.

...did we blow a gasket in 2003 and the engine is running down?

TAG, please look at the following graph (data from OMNIweb) .

1292027427_ScreenShot2019-12-02at2_37_29AM.thumb.png.968bb486ba2e187e3fc8180c5e8ae0da.png.

Is this graph an explanation as to why there was a dramatic lowering of the Ap over the past solar cycle?!?  Have you seen this discussed before?

Assuming we can believe it (meaning, the data has at least ballpark accuracy, whereby data acquired from different satellite platforms is properly accounted for), the above graph is telling us that there has been a dramatic drop in the volume of matter in the solar wind, starting about 20 years ago.  Do you agree?  What do you think about that?

 

On 11/27/2019 at 2:32 AM, The Atmosphere Guy said:

My principle concern is the sudden anomalous drop in the 'Ap' chart that was noted at the start of this thread. That, coupled with the apparent 'wind down' evident from 2003, is I would suggest, unparalleled in our data.

I think the above graph provides reasons for the “anomalous drop” in the Ap.  The Flow Pressure can be derived by multiplying the Velocity of the wind (squared) by the ‘mass density’ of the proton matter (with an adjustment for alpha particles and electrons).  Flow Pressure is plotted below, along with the sunspot number:

1160671654_ScreenShot2019-12-02at3_00_29AM.thumb.png.c21b24774cd43f4c91eea48d7e31e141.png

 

It would make sense that a lower Flow Pressure is, generally, going to result in a lower Ap, yes?

Edited by theartist
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The ‘K’ index (and its ‘A’ derivatives) is defined as, in essence, a mathematical representation of the intensity of the impact of solar storm energies – in all of the various forms – on the earthly environment. That would include both CMEs from sunspots and the solar wind, so a variation in flow pressure/velocity and density – such as that from a coronal hole or similar disturbance would be measured as a variation in Ap.

Your graphs do show what appears to be a general slowdown, in addition to the 2003 surge and Halloween Storm followed by the ‘03/’09 drop off.

      1058022682_PlasmaSpeedmarked.thumb.jpg.d32618c03c99da777a0b91990168bf1c.jpg             455811390_CliffEdgeTagged.thumb.png.e31fa9756ac7e39b34d9ce2d67287fe3.png

 

We seem to have an interesting position just at the moment, Solar wind is weak, the sun is spotless, TC index is declining steadily, coronal hole activity is fading – is this the calm before the storm, or a continued run-down? Ap levels are likely to be even lower than my earlier guess possibly now 4 and then 3, depending how Boulder chooses to round the figures – up or down.

 

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I’ve been following the conversation in this thread and I must say it’s been a great one to follow. I love the flow and trying to uncover what’s going on with our Sun with you guys. I’ve been a “wisdom scholar” learning about the Sun and how it effects us on Earth since 2010 when the Chili quake happened. I’m an intuitive, I notice patterns. I believe we cannot say if this is the calm before the storm but I think we can say it “feels” like a deep.. deeeeep minimum. It’s definitely creating climate change on a quicker scale than we may even realize right now.
My question is where is the Suns location exactly? Is it in a dense part of a cloud in the Local Bubble? Is that the culprit?

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On 11/29/2019 at 12:51 PM, theartist said:
  • Scenario 1 is defined by the above annotated TSI graph and ensuing discussion, whereby Solar Minimum Nadir (SMN) is in Feb-Mar 2020 (give or take a month 🤪). 
    • Probability: 65%.
    • SC25 strength consequences: similar to SC24, or slightly weaker.
  • Scenario 2 is one in which SMN is happening now, in the month of November, or before. 
    • Probability: 25%.
    • SC25 strength consequences: could be significantly stronger than SC24.
  • Scenario 3 is one in which the SMN does not happen until sometime in 2021 (per the Upton&Hathaway paper cited above). 
    • Probability: 10%. 
    • SC25 strength consequences: Levels not seen in the last 200 years, as Kitiashvili said.

I think the possibility of SMN to have already happened is much less than 25% probability.  Two months prior to the last SMN, a 'significantly large' photospheric magnetic structure was observed above the 32deg latitude, which was followed in the next month with another larger photospheric magnetic structure, above 32deg latitude, producing sunspots. (This is discussed in the thread titled, "Synoptic Magnetograms; SC24 Minimum Forecasting". ) In addition, that latter structure resulted in the GOES X-ray flux registering >B Class perturbations. If SC25 is to be as strong or stronger than SC24, I think high-latitude (i.e., >32deg) photospheric magnitude structure(s) will need to appear in or before the month of SMN (based upon a comparison, specifically between the SC23/24 and the SC24/25 transitions, of temporal characteristics of the Sunspot series, the F10.7cm flux, the TSI, etc.).

Edited by theartist

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