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Ap & aa Indices and Solar Minimum

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344067246_ApIndex().thumb.png.cad5059f18430aab6f92c6c372de0c2e.png

The source of the data is the ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/ap_monyr.ave file found here.  (The data has been smoothed with a centered-moving-average.)

Thank you to The Atmosphere Guy for pointing out, in this thread yesterday, the anomalous Ap behavior over the past solar cycle. 

Edited by theartist
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My Pleasure - Glad to assist!

This chart shows, perhaps even more clearly than the rough ones I used , the shallow 30 year cycle bottoming in 1935, 1965/6 and 1997/8 and the tendency for ‘Ap’ to bottom out in the year or two immediately following solar minimum. These are aspects that appear to be rarely, if ever, openly discussed.

Just what happens now is open to wild speculation. Just a bump in the road and then back to normal? Or did we blow a gasket in 2003 and the engine is running down? Guess you just have to roll the dice!

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17 hours ago, The Atmosphere Guy said:

Just what happens now is open to wild speculation. Just a bump in the road and then back to normal? Or did we blow a gasket in 2003 and the engine is running down? Guess you just have to roll the dice!

An underlying objective with most of the threads I've started (or participated on) in this forum over the past few months is to arrive at a Forum Forecast for Solar Cycle 25, as discussed in the following thread, SOLAR CYCLE 25 Prediction/Forecast by SpaceWeatherLive Forum.  Your input, in arriving at a forum concensus for the Forecast, is welcomed.

Both the aa Index and the Ap Index are plotted (after smoothing) on the same graph below.  The aa Index data was downloaded from International Service of Geomagnetic Indices.

1137321412_aaApIndices.thumb.png.a03dd4ffb308c3d8c539b28bbb1364cb.png

Excellent agreement between the two Indices is observed.  An advantage to the aa Index is that its data goes back to 1868.

Edited by theartist
Fixed graph typo, and formatting.

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Below is the above graph plotted again, but extended back to the beginning of the aa Index.

1029697412_aaApIndices1868-.thumb.png.b1b561a97f7a4f66e5d14c6871f2c42e.png

 

Solar Cycles highlighted in the above graph demonstrate similar behavior, in terms of ballpark-magnitudes (including during Solar Minimum), to that of SC24; they are:

451057678_ScreenShot2019-08-29at4_08_42AM.thumb.png.706d74792f96fce9f76cc13e6dde8a8f.png

Without further information on the initial half of SC11's aa Index, we can exclude it from the above list.  The others, by nature of demonstrating similarity to SC24, are candidates for potential similarity to SC25.

Edited by theartist
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A very constructive piece of work!

We can note within the extended chart that the deep dip around 1901/3 would seem to be in line with the ‘30 year’ concept. If this holds true we could possibly anticipate the next deep point to be around 2030/31; i.e. the end of cycle 25 and in line with the NOAA/NASA preliminary forecasts.

The chart also seems to display an almost sinusoidal underlying shape to the graph seemingly implying that we are now into the down-slope of the half cycle stretching back to around 1900. This would seem to re-iterate the impression given by the ‘Butterfly Chart’.

The size and shape of SC24 on the chart is not dissimilar to that of SC15. Would it be stretching things a bit to guess that SC25 will be similar to SC14, following the ‘Half Cycle’ concept and leading us to the 2031 deep dip?

On that basis we may assume that the defined SC24/SC25 minimum would be ‘about now’ and that the shape of SC25 being reasonably close to SC14, this would put us very close to the NOAA preliminary forecast.

May I make use of your Chart?

Edited by The Atmosphere Guy
better phrasing
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Great post, but we need to keep terms straight to clarify understanding.  What you term "the NOAA/NASA preliminary forecast", is actually two different forecasts discussed in this thread, Solar Cycle 25 Predictions/Forecasts by 'The Panel' & NASA, and they have significantly different consequences.  

  1. In this press releaseNOAA is associated with what I term the 'Panel forecast'.  
  2. I term the 'Kitiashvili forecast' as the 'NASA forecast', since NASA latched on to it in their press release here.

The large sinusoid you suggest is possibly analogous to the cyclical concept shown in the following figure:

1051519425_ZharkovaCycles.thumb.png.77fcb7cbb1002d502f500960eabe0326.png

Figure source: "Heartbeat of the Sun from Principal Component Analysis and prediction of solar activity on a millenium timescale", V. V. Zharkova1,2, et.al., 2015.

The "half-sinusoid" appears to be roughly 17-18 solar cycles in the above figure.  I annotated the figure with two circled scenarios:

  1. Scenario 1 is an example of the 'Panel Forecast', whereby intra-cycle squelching occurs rather quickly, possibly within one cycle (over the SC24/25 transition, for example, such that SC25 is bigger than SC24).
  2. Scenario 2 represents one example outcome of the 'Kitiashvili/NASA Forecast', whereby intra-cycle squelching may require a few solar cycles to accomplish shake-down before the ramp up into the next "half-sinusoid". 

The scenarios I describe above are for purposes of illustration as to how the respective forecasts might fit in the context of decadal-to-millennial timespan cyclical solar activity, without inferring either 'The Panel' or 'Kitiashvili' actually subscribe to the cyclical nature shown in the above graph.

I thought I had uncovered a 'Bremen Metric' (discussed here) that was quickly going to nip the Grand Solar Minimum talk in the bud.  It inferred a short SC24, and thus a likely larger SC25, in the likes of Scenario 1.  However, if the 'Bremen Metric' breaks down, which looks quite possible at this point, then that might entail a double-dip of the Bremen Composite Magnesium II Index during this current solar minimum period, which would be a first.  It is generally understood a lower intensity of SC25 will be more likely the further SC24 solar minimum drags on, because the magnitude of the polar magnetic fields continue to decrease over a prolonged solar minimum

16 hours ago, The Atmosphere Guy said:

May I make use of your Chart?

It is posted on a publicly available site, using publicly available data sources, so...I hope that answers your question.😊

Edited by theartist
phrasing

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On 8/29/2019 at 8:00 AM, The Atmosphere Guy said:

with the ‘30 year’ concept

If you will, consider a 4-cycle phasing, rather than 3-cycle, as I've shown below with added annotation to your figures (found here):

2004584876_TAG14-cycle.thumb.jpg.3f6417e0120a113433089d81ed8ddeee.jpg853427179_TAG24-cycle.thumb.jpg.ccaada39871914ab640865275f80bcd9.jpg

After-all, a full magnetic cycle is two ~11-yr half-cycles, so any cyclical relationship will likely involve an even number of half-cycles.

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On 8/29/2019 at 8:00 AM, The Atmosphere Guy said:

the half cycle stretching back to around 1900

Let's first add a series of '4-cycles' to the aa Index chart:

2143592646_aaApIndices1868-4-cycle.thumb.jpg.11e087ade5ba3dc8134b7239d230ae4c.jpg

 

Now then, let's entertain the idea of the 'sinusoid you' were seeing in the same chart:

441505420_aaApIndices1868-Sinusoid.thumb.jpg.ff4d563574287207ec108479a309dd63.jpg

Now, the duration of two 4-yr cycles is ~88-yrs, which is the duration of a Gleissberg Cycle!   Two Gleissberg Cycles (a full 'sinusoid') is ~176 yrs; doubled again is ~352 yrs, where the plot thickens, for if you have read the Stochastic influence on solar cycle activity: planetary clocking? thread, or the Article published on Nature.com predicts new Maunder Minimum, you may recall that there is an approximate 360-yr cycle of repeated planetary clocking!

Edited by theartist
fixed graphs

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Some fascinating stuff in this data, though after a lot of playing with the it, I tend to stick to the ‘30 year’ concept.

As is usually the case in these areas, restricted data availability pushes any assessment into realms where mental gymnastics and the imagination become ones primary tools. Clearly, there are several cycles at work here and the further back we try to push things the more they seem to come unstuck!

Just as an aside, I have opened a new topic on the link between Solar ‘Kp’ impacts and the development and acceleration of tropical storm structures.

– Any thoughts ?

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On 9/1/2019 at 8:35 AM, The Atmosphere Guy said:

I have opened a new topic on the link between Solar ‘Kp’ impacts and the development and acceleration of tropical storm structures.

One thing to keep in mind is that geomagnetic disturbance goes up around the equinoxes; correlation is not always causation. Nonetheless, the most obvious story with regard to Kp and tropical storms would have to be the anti-correlation, no?  Haven't the storms intensified over the past few years, whereas, the Kp (and solar activity in general) is dramatically lower than what it was 30-40 years ago?  How do you explain that?  What has changed?

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Good Question!

The equinoctial effect you mention is commonly known as “Russell-Mcpherron” effect whereby activity is known to be high at the equinoxes, dipping low at the solstices; however when the ‘Kp’ is generally high, the atmosphere overall is generally more ‘puffed up’ (good for clearing satellite junk!) atmospheric profiles are steeper and individual impacts less noticeable, less effective and atmospheric profiles become the principle steering influence in storm activity. Whereas when background levels are generally low the effect of a sudden major impact is far greater and ‘coastal interaction’ becomes the principle steering influence. Both of these factors can be seen in the behaviour of “Dorian” which is likely to stall as it encounters the Florida coast then follow the coastline north.

The site http://eng.sepc.ac.cn/ApForecast.php gives a good impression of the level of impact, while the general subject is discussed in

https://howtheatmosphereworks.wordpress.com/about/solar-activity-and-surface-climate/ 

The coincidence between solar equinox effect and the surface climate being just in the right, late summer, condition for storm formation will always raise the risk. This risk may be raised at solar minimum when CH outbursts are more significant.

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6 hours ago, The Atmosphere Guy said:

however when the ‘Kp’ is generally high, the atmosphere overall is generally more ‘puffed up’ (good for clearing satellite junk!)

"Generally high" over what time frame are you referring to?  Are you saying that the atmosphere 'puffs up' and then shrinks with each geomagnetic storm?  We know that the thermosphere cools and shrinks with every solar minimum, as there is a small (much less than 1%) change in the Total Solar Irradiance over the solar cycle. Are you saying the geomagnetic activity also has a direct affect on that "puffing up" beyond its normal contribution to the solar cycle irradiance wax/wane?  I'm not being pedantic; rather, just trying to keep gibberish out of making broad sweeping cause-and-effect assertions with regard to something as complex as earth's atmosphere.

6 hours ago, The Atmosphere Guy said:

when background levels are generally low

"background levels" of what?

6 hours ago, The Atmosphere Guy said:

atmospheric profiles are steeper

What does this mean? Are you referring to temperature gradients?  Surely the effect of temperature gradients and their changes relative to geomagnetic storm activity has long been studied to some detail, if not fairly well understood by now?

6 hours ago, The Atmosphere Guy said:

the effect of a sudden major impact

There is a lot being implied in your statement here.  The terms "sudden" and "major impact" are relative to what?  Something different than the normal course of geomagnetic disturbance observed throughout the solar cycle?

Edited by theartist

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Firstly can I apologise if some of my paraphrasing was a little over simplistic, one tends to get that way sometimes!

Perhaps I may best recommend a study of the data outlined in ‘Solar Activity and Surface Climate’ section together with that on ‘Storm Analysis’. This, again, is a condensation of years of research in this area, much of which goes against many of the established warming theories. I would be delighted if you would produce your own charts supporting or refuting the conclusions in those sections.

We can see that the data closely correlates the effect of influence and response, far too commonly to be mere coincidence, although it is self evident that the precise mechanism is open to conjecture.

When I referred to ‘Generally high or low’, it is fairly well established that over each solar cycle, heating, expansion and cooling is an accepted phenomenon, perhaps best related to the TC index. Background levels refer to the ‘Non-explosive’ Ap/Kp activity. We have, for example, seen a very low background level until the explosive impact of the end of August – as you may see in the Ap Forecast chart.

The term ‘Atmospheric profiles’ refers to both thermal and pressure profiles as measured in the atmosphere charts used. These can be seen to respond in an almost ‘tide like’ action under the influence of Kp/Ap activity.

 

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TAG, you have brought up some good ideas regarding the cyclical nature of Ap and its effectual comparison to the Sunspot Number.  But as good as those ideas are, in the pursuit of scientific truth, I would caution anyone drawing the conclusion from them that we are now going into something as drastic as a Maunder Minimum (where sunspot activity virtually collapsed for several years, if not decades).  The data (including a deeper look into the specific nature of planetary clocking), in conjunction with the volume of literature I have read so far, does not appear to indicate that; at least, it is far from conclusive to that effect.

After reading more of the scientific literature on the cyclical nature of things (there is a lot more to cover on the topic), particularly related to the Gleissberg Cycle, I do think the possibility of another three solar cycles (to add to the one we just had) of suppressed Ap activity is worthy of consideration.  But this is in light of focusing on an ~88-yr cycle sinusoid (i.e., Gleissberg Cycle), rather than the  larger harmonic I drew above. Maybe you can see the smaller ~88-yr sinusoid in the following graph:

Sinusoid temperatures.gif (Figure source.)

With this understanding, the manner in which remainder of the current solar minimum period shakes out could be quite telling for the pattern of the next three solar cycles, which makes watching it even more exciting. 🤓 

Edited by theartist
Added the word "solar" to "cycles" for clarification.

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Just for interest’s sake, I have put together some data from the ‘Ap’ records which may be informative.

1445785296_CR2219-2223Jpg.thumb.jpg.5034860c78b422add4d92ebdb0cff443.jpg

Firstly the charts from Carrington Rotations CR2219 to CR2223 which show the recurrent behaviour of the so-called ‘Lighthouse Beam’ coronal hole (CH941 – CH938 – CH935 – CH932 – CH928 –etc) over recent months. There are, from this data, some interesting coincidences: We can note the coincidence between CR2221 data and development of Hurricane “Dorian” together with CR2222 data and Hurricane “Lorenzo” which became the furthest north and furthest east Category 5 ever recorded.

2142595107_CR1859CR2033CR2207c.thumb.jpg.b861dcd044988c79db4db2b5956995e8.jpg

Extending this thought process back in time we can examine the link between Carrington rotation CR1859 data and Hurricane “Andrew” in 1992 (August 23/24) and CR2033 data and Hurricane “Katrina” in 2005 (August24/26.)

CR2207 (August 2018) shows unusually low, flat, ‘Ap’ activity – coincident with zero Hurricane activity in that month – until August 26th when a sudden, out of the blue, burst of activity was followed by development of “Gordon” and “Florence” in the Atlantic and “Norman” and “Olivia” in the Pacific. The noted August 26th outburst was also coincident with activity at the Solar Observation Laboratories – but that is a separate subject!

Late August does seem to be associated with sudden, significant ‘Ap’ outbursts; this is thought to be associated with Russell-Mcpherron effect.

1106062051_HalloweenSuperstormOct2003Jpg.thumb.jpg.0efa03d7595c5577ec4ea8381aba71f0.jpg

Of interest is also the "Halloween Superstorm" of 2003; shown here in CR2009 data (October 29/31). This outburst went 'off the scale' and is noted as preceding the steady fall-off in 'Ap' activity overall that we have seen since that point in time.

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15 hours ago, The Atmosphere Guy said:

Of interest is also the "Halloween Superstorm" of 2003; shown here in CR2009 data (October 29/31). This outburst went 'off the scale' and is noted as preceding the steady fall-off in 'Ap' activity overall that we have seen since that point in time.

Wow, interesting!  Spaceweatherlive produced a detailed YouTube video on the storms surrounding that event.  And 'coincidentally'(?), that unusual solar activity occurred well into the declining phase of SC23, around a Jupiter/Uranus Superior Conjunction.   I just discovered this 'coincidence', and consequently added it to the thread titled,  "Stochastic influence on solar cycle activity: planetary clocking?".  Thank you for bringing this up!

You might find it interesting that a 3-cycle pattern in the Ap data was discussed in the paper by Ahluwalia (1998) which n-adventurer cited over on the thread titled, "SOLAR CYCLE 25 Prediction/Forecast by SpaceWeatherLive Forum".

Edited by theartist

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Perhaps relevant to note that the elevated level of overall solar activity in 2003 has been associated with the "European Heat Wave - 2003" said to be the hottest since 1540. (Certainly a hot one, I was there! ) That, and the cold winters around 2010 (the "Snowmageddon" years) associated with the R-M dips in 'Ap' of those years, are discussed in my section on the subject in https://howtheatmosphereworks.wordpress.com/about/solar-activity-and-surface-climate/

Fascinating when theories start to come together !

1055334155_2003110700_11.jpg.d02c73f0adddbe85ef5614092c24e45c.jpg 1970744737_2010110700_11.jpg.1358d0bc6cf71d212da01b702a040035.jpg 851468887_2019110700_11.jpg.2cfe66373174b9dcb1aa6b34eecf05f3.jpg

Any good with Met charts? The above are the charts from 00UT, 7th November, 2003 (heat wave year), 2010 (snowmageddon year) and 2019 (now), in that order.

A wise man might see fit to invest in warm underwear for the coming winter!

Extending this to the debate on SC25 might imply that the decline in activity is deeper now, and potentially to continue longer, than the SC23/24 minimum.

Edited by The Atmosphere Guy
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On 9/1/2019 at 8:35 AM, The Atmosphere Guy said:

I tend to stick to the ‘30 year’ concept.

Well if a full-cycle is ~360 years in length, and there are 12 Zodiacs through a complete cycle, then that would make a Zodiac 30 years in duration.  🤔  This just popped into my head, and I don't know if it is true.   Maybe Michele would know.

The following article says the sun sits in a new constellation every 2000 yrs: "What is the zodiac?"  The first commenter to that article states, "(the) star pointed to by the Earth’s north pole—the North Star—changes over time. After 25,772 years the Earth’s north pole completes one cycle of its movement. ...One twelfth of a Great Year—a period of 2,147.67 years--is called an Age. As the constellations move in relation to the signs, the sign occupied by the Sun at the time of the spring equinox changes. Each age is named for the constellation that is rising on the spring equinox. During the past 2,000 years, the constellation Pisces has been rising at the time of the spring equinox. The Earth is currently moving from the Age of Pisces into the Age of Aquarius.
A single Great Year of Western or classical astrology is approximately equal to five Great Cycles of the Mayan calendar. According the Mayans, a Great Cycle equals 13 bactuns or a period of 5,125 years. The current Great Cycle ended on December 21, 2012."

🤔  So an Age of 2147.67 divided by 12 equals 178.9725 yrs, which is 2x Gleissberg Cycles!

Edited by theartist
spelling correction

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Another little addition to the files, if we examine the data surrounding the famous "Perfect Storm" of 29th October 1991, we can see that the influence of solar impacts 'May' be relevant to other surface storm activity, not just the tropical variety. Gets more interesting the further you push this concept. The immediacy of reaction tends to imply that there is more to the concept than just atmospheric expansion or even shock wave impacts. Electromagnetic effects have been proposed; a storm may be considered as a rapidly rotating conductive mass active within a magnetic field. Change or increase that field and rotation would/could/should increase.

569741335_IMG_20191113_0001PerfectStorm1991.thumb.jpg.4d27a600e889dc058e25ac6753b282b5.jpg

 That particular period was very active overall from a solar impact viewpoint.

Edited by The Atmosphere Guy
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On 11/13/2019 at 4:41 PM, The Atmosphere Guy said:

Electromagnetic effects have been proposed;

Interesting you should say that, because there are A LOT more aerosols in the atmosphere due to anthropogenic activity, and you may remember from school (or from rubbing a balloon on your sleeve) that non-conductors can develop electrostatic charge, so possibly non-conductive (originally electrically neutral) aerosol particles could develop electrical charge as well.  The sun electromagnetically stirs up the ionosphere, and closer to ground in the thermosphere troposphere, where a lot of weather is generated, anthropogenic activity puts A LOT of electromagnetic energy into the atmosphere. So combine all of THAT particular type of anthropogenic activity and what do you get?  I have no idea, but possibly that type of anthropogenic activity, in lieu of CO2 (which makes up less than 0.05% of the atmosphere) should be considered in 'abrupt climate change' or Anthropogenic Global Warming (AGW), yes?  What do you think about those ideas?  Do they hold any merit?

Edited by theartist

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The irritating thing is that – as with all things in nature – it doesn’t always hold true. There are times when there appears to be little or no direct connection between the solar impacts and storm activity. Perhaps some, but after a delay, or even not at all. Identifying the how’s and why’s may take a lot more analysis!

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