A Coming Grand Solar Minimum Or Not: Predicting Solar Minima and Maxima
Earth is currently experiencing weakened solar activity not witnessed by living persons. What is on the horizon regarding geomagnetic storms or climate effects? Is a “grand minimum” (Maunder Minimum) imminent? This article touches on these and notes in some detail predictive tools – to include their limitations – recently tested which may yield reproducible clues.
Solar Dynamo 1: Minima and Maxima “Machinery”: Linked But Separate, How It Ionizes Our Atmosphere Via Solar Flares
The solar dynamo theory partly holds that the sun is driven by a 22-year periodicity (the “double-Schwabe” Hale magnetic cycle) involving deep inner solar maxima and more-identifiable solar minima-field “machinery.” Magnetic fields thus spun show:
- Solar irradiance variation (in maxima) and
- Ejected (magnetized) solar plasma clouds (from e.g. Coronal Mass Ejections [CMEs]) in minima.
Periodicity (Schwabe/Hale) yield group sunspot numbers (RG) for obtaining proxy data in knowing about solar irradiance variability in the sun’s maxima field. Magnetized plasma is a minima-field indicator (nanoteslas [nT]). Yet parameters like RG (or, the maxima indicator of sunspots) and ejected magnetized solar plasma in magnetic density flux (nT) do not culminate together. They cause different earth effects too. Thus they are studied as separate – if revealing – phenomenae.
Image 1. Minima (in top/bottom-outflow) and maxima (sideways-outflow). The two forces are continual and vary greatly in output yet do not work together, and cause different earth effects. (Photo: Solar Dynamics Observatory [SDO], NASA).
The sun is watched for sunspots since the less radiation-emitting sunspots act as “bearers” for how strong solar activity might be – each new cycle heralded by spots with opposite polarity (more spots equals more solar activity). The 22-year Hale Cycle waxes and wanes in amplitude, not ceasing until our star dies.
Chromosphere-ejected emitta due to very sudden solar flares effects earth’s magnetic envelope over time after residence in the 50-km high earth stratosphere, winnowing its way down into the troposphere. This climate / electromagnetic disrupting plasma could contain both Solar Energized Particles (SEPs) thrown from CMEs, cosmic rays (particles emanating from Type 1A supernovae pushed into the weak sun-created heliosphere) and residual plasma/radiation (Gamma, Ultra Violet [UV] / Extreme UV [EUV] X ray, etc.) drawn up near active regions; e.g., faculae and plages.
Emitta is literally shot out through the more polar-oriented coronal holes via the solar wind. This ionized wind – hyper-hot compared to sun surface temperature – propagates millions of miles and, if pushed out enough into space from a CME blast, “corkscrews” particles into earth’s currently-weakened magnetosheath without any heat loss. Earth’s magnetosheath is sun-steered, ballooning in solar high-activity periods, becoming flaccid in weak-solar times. Solar flares accelerate particles with heat and, with CMEs, usually strike outward simultaneously. For all that, these sword stabs behave nonlinearly, appearing only at certain solar latitudes and longitudes and vary greatly in force – X Class the highest. SEPs, much like poorly-named cosmic rays (they are actually particles) are a main ionizing factor in earth’s stratosphere. The ionization rate in the upper earth atmosphere varies with cosmic ray intensity and SEPs or both. This intensity has reached levels not withstood by earth in at least 100 years due to a weaker sun. NASA estimates that cosmic rays have increased by 13{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} since 2015 alone.
Image 2. “Old TV-screen fuzz” is particles like SEPs, perhaps along with cosmic rays, out of the sun. (Photo: Solar and Heliospheric Observatory [SOHO] NASA-ESA)
Solar Dynamo 2: Minima and Maxima Machinery Cosmologically Considered: Stable Core and Unstable Tachocline
The solar dynamo theory precludes accepting outer forces acting on the sun regarding exterior fueling or forcing. Sun-strength calculations (measured at the “dynamo heart” – the tachocline) show accelerations caused by planets disappear in the accelerations actually observed inside the sun; they are too small by far to cause the accelerations observed. (Other theories are bypassed here.)
Let’s consider the self-powered sun. Its core is stable; the radiative zone less, and it is extremely unstable in the convection zone containing the solar minima “machinery.” The convection zone also contains the extremely volatile, shearing tachocline. It is labeled this since its physical behavior resembles earth oceanic thermoclines; cold water sacs floating over or under warmer. It might be termed the sun’s “jet stream” or “dynamo’s heart.” The tachocline generates the Sun’s magnetic field via a deeply-flowing circular electric current. An electric-current “seed field” generates at levels where different solar latitudes rotate at different speeds (that is, “differentially”) while interacting with deep-seated convective motions, amplifying magnetic field strengths. It reverses every 11 years (the Schwabe Cycle – half the Hale) kicking off sunspot activity. Highly-conductive, convecting gas moving upward ‘granulates” in the shallow photosphere right below the chromosphere. Yet inertial core spin and the tachocline involved in internal rotation versus each other is what gives rise to possibly -and repetitively- detecting prolonged (“grand”) periods.
Solar Periodicity In Amplitude Modulation: Some Quantified Cycles and Models
When can grand solar minima or for that matter maxima be predicted? They cannot. (Even “normal” minimas and maximas in the Schwabe Cycle are not 100{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} predictable.) We do know sometimes solar maxima robustness (amplification) is high and at others low (“loops” in Figure 1.). These “normal,” sometimes exaggerated “ups” in maxima and “downs” in minima amplification are, as pointed out, witnessed in the 22-year magnetic Hale Cycle. Yet the minima and maxima machinery as it behaved 400 years ago must be reconstructed to “see” the past. Proxies reconstructed thus to measure the Total Solar Irradiance (or TSI) variability in minima are Aamin – magnetic density flux, and in maxima, Rmax – or sunspot counts. Amplitude modulators of periodicities delineates TSI – which gives TSI’s spectral imprint as well (wavelengths of light radiation, UV, etc.) – a climate modulator growing in overall importance in understanding the sun-earth connection.
Amplitudes involve oscillations. We note that linear systems’ oscillatory modes with stable boundaries are harmonics functions. So enter wavelet base functions models. Additionally liquid solar core motions could lead to variations in the geomagnetic field and in the Earth’s rotation rate: Length Of Day (LOD) variations bear some relationship to solar rotation, as well. The base functions split the modulation in the Hale solar cycle into the Gleissberg Cycle and, further, into two quasi-harmonic oscillations. The Hale periodicity’s amplitude modulation is factored as the Gleissberg Cycle, which is coincidently close to the total solar Barycenter Shift of 179.8 years (this inertial internal solar disturbance having been known since Isaac Newton with bearing on long-term solar variability). Again, the Gleissberg Cycle has the two quasi-harmonic oscillations; (1.) a symmetrical Gleissberg (semi-“secular” = or, c. half century) oscillation and (2.) an asymmetrical Gleissberg (bi-decadal, or, c. each 20 year) oscillation. Both symmetries are linked with solar equatorial torsional oscillations in the unstable tachocline. This is then considered in conjunction with barycenter inertial spin cycles – like a spinning toy top prone to vibrations – in inner liquid core spin and the convective envelop. (Torsional oscillations could act to stabilize the tachocline’s convection zone systemic motion, transferring angular momentum horizontally out from the core “latitudinally.”)
What is still unexplored is what causes these vibrations at certain transition points in time or, crossed minima and maxima data coordinates leading to “chaotic amplitude leaps” – either upward or downward, sometimes lasting for more than 50 years; or, what gets labeled “grand (solar) phases” (prolonged solar maxima [upward] or minima [downward]). A third cycle – the c. 200 yr, Carbon 14 (C14)-isotope delineated Suess, or, de Vries, Cycle – is pointed out here as well relative to the quite deep-time Hallstatt Cycle, since quantifying the latter has shed light on long and short term solar effects on climate.
Figure 1. Thick lines represent the symmetrical, semi-secular Gleissberg quasi-harmonic. Thin: the asymmetrical Gleissberg quasi-harmonic. Both are tied to variable Hale periodicities, These are linked to the equatorial tachocline solar oscillations. Left abscissa = Length Of Day (LOD) as tied to solar rotation and the periodicities. (Modified graph after de Jager et al 2010.)
Prolonged “Grand” Periods and Transition Points: Predicting Long-Term Solar Activity
Figure 1. points out that magnetic-field phase diagrams (plots of Rmax against Aamin) agreed with amplitude loops upward or downward at critical intersection points made by proxies for minima and maxima. Proxies:
- Maxima (when a sunspot-amount of 93.38 was reached, the “sunspot coordinates”: Rmax) and
- Minima (at 10.34 Nanoteslas [nT] for magnetic flux density, “geomagnetic index coordinates”: Aamin )
at “transition points.” (These “transitions” happened in the years 1620, 1724, 1788, 1880, 1924, and 2009.) An important downward amplitude overlap occurs in the two “chaotic” Gleissberg quasi-harmonics at 1620 and again in 1968 (“downward-spiraling Schwabe Cycles”). Magnetic-field phase diagrams delineating the overlaps hint either at a return to normal “regular” oscillations or -worst case- to a grand minimum. It is not clear which. Since the 1620 amplitude overlap ushered in the Maunder Minimum, the current epoch appears headed the same way. Periods between c. 1724-1924 represent “normal (or, regular) solar cycles” in that the periodicities’ amplitudes’ quasi harmonics have a “relaxed-fit” across these epochs. (The Dalton Minimum [D in Figures 1., 2., 3a.] does not factor as a “grand” type minimum.)
A Coming Grand Minimum Or “Regular” Cycle? Attempts To Predict Short-term Solar Activity
Another chaotic transition point passed in 2009 (see Figure 1.). An overlap is apparent (the amplitude loop extent downward is shown in Figure 2. for 2009). Solar Cycle 24’s minima value (Aamin) was known from observations before 2012. Nonlinear relations between the preceding minima and the subsequent maxima (Rmax) – as sunspot – value (from c. 1924 – c. 1994) were used to try and improve solar activity-prediction.
Models in magnetic-field phase diagrams showed the semi-secular oscillation amplitudes and lengths compared well with each other during the past Grand Maximum (from c. 1924 – c. 1994 – see Figures 1. and 2.) and the “grand” Maunder Minimum (c. 1620). At maximum the semi-secular oscillation was negative. That explains why the predicted values (green and blue triangles) fall below the respective regression lines (see Figure 2.). However the variability of the relative phases and strengths of the bi-decadal and semi-secular oscillations are poorly known. Extrapolation showed that the bi-decadal and the semi-secular oscillations would be negative at Solar Cycle 24’s usual sunspot maximum. The smoother value showed 81.8 in reality at Solar Cycle 24’s expected maximum in 2014. Solar Cycle 24 turned out to be double-peaked and was the weakest since Solar Cycle 14 (c. 1902-1913). These models predicted not less than 50 and no more than 74 sunspots for the smoothed maximum sunspot number for Solar Cycle 24. Their prediction – made in 2012 for 2014 – was off by 7 sunspots in the maximum value. Yet, these findings still indicate that either a “normal” (regular cycle) or a grand minimum is imminent going into Solar Cycle 25 – which began in April 2018. This either/or confusion arises from not being able to trace predictability paths in magnetic-field phase diagrams with enough precision from solar polar field strength (DMmax) and Aamin) in proxies for the 20th Century to reach an exact determination.
Figure 2. Sunspot counts revealed by phase diagrams in solar long (and even short) term activity prediction. Note the models of the data revealed a grand maximum kicked off roughly around 1924. The green stars represent the closest the model calculation for maximum amount of sunspots in Solar Cycle 24 could reach– the blue diamond showing that Solar Cycle 24 was the weakest since Solar Cycle 14.
The Hallstatt Cycle: No “Grand Minima” For the Next 2,000 Years?
That either a “normal” (regular cycle) or a grand (a “Maunder”) minimum is appearing sometime in Solar Cycle 25 creates uncertainty. However other solar-cyclical factors are at work helping to decide the issue. For this another quantified, delineated deeper-time cycle – the Hallstatt – is examined. The last millennium is considered regarding solar behavior in this reconstruction. It is characterized by a succession of several grand minima; the Oort, Wolf, Spörer and Maunder Minimums (see Figure 3A.). The kind of cycle imminent in this – grand or regular – depends on the sign of the bi-millennial (c. 2,000 year) Hallstatt Cycle. One researcher concluded that grand minima have only occurred in groups during the Hallstatt Cycle’s minimum periods. (This cycle has a period of 2,300 +/- 50 years.)
But whatever arises will not be evident until Solar Cycle 25’s expected “usual” solar maximum shows its maximum sunspot count, due to the data non-robustness mentioned above regarding magnetic-field phase diagrams. If long-term solar activity indicated by the Hallstatt Cycle is also applicable to short-term solar behavior, it could tell us by roughly the year 2024 in such model data calculations.
Figure 3a. (Left) and Figure 3b. (Right) Data by three researcher groups (Figure 3a. ) against basic plot for the C14-delineated Hallstatt Cycle length (Figure 3b.). It is seen that since 1935 AD the sun-earth relation is in a positive Hallstatt phase. Reconstructed data (left panel, Figure 3A ) reveals no grand minima occurred in that c. 2,000 year time frame. (The “D” in Figure 3a’s right panel denotes “Dalton” or, non-grand, solar minima.)
The major limitation to this entire prediction-set is that linear models are not precise for describing nonlinear open boundary systems like planets and stars (our sun) which change in frequency and amplitude as they oscillate in time. Nature is not a math modeling laboratory. Additionally data used for these models were collected from earth-based motion-and-atmospheric-biased recording stations for most of the last 400 years at all points on earth, in some case by questionable collectors. This skews data results including radioisotopic imprints in ice cores etc. (C14, Beryllium 10 [Be10] etc). Future solar research on sun-earth climate must use as much space-garnered data as it can. Mathematics used to describe the data must handle more parameters and iterations, such as base functions of compact support and hence, higher technological computational (for example Cray) power is required.
Summary
What of escalating solar flare-threats to earth? The sun does not radiate in all directions at once in simultaneity as if powered linearly. Solar flares/CMEs should often be near or at X class and strike on or very close to earth’s magnetic weak spot for dreaded “1859-events” to occur. A nonlinearly-behaved star with some 1,300,000 km in false diameter must strike a planet 12,800 km diameter dead-on at near X Class in one of its c. 4,000 km wide weak spots – preferably on the more-magnetically calm earth night side. Nearly all these factors combined for the famous 1859 event. But that the sun is magnetically weaker than just 20 years ago means that the earth’s magnetic sheath is also weaker. As there is no perfect correlation between solar flare reduction in solar magnetic weak periods vs. strong ones, it’s assumed that “1859 event’s” dangers are increased and not reduced. Earth’s magnetic sheath in 1859 was weak compared to how it was at Solar Cycle 23’s beginning (1996). At Solar Cycle 24’s end, earth’s magnetic sheath is currently much more like that which was protecting earth in 1859.
What of climate? The solar imprint on climate is measurable via longitude, latitude and height: Delta T statistical averages of say northern hemispheric temperature are mere academic summaries of generalities. Just touched upon here were climate modulators such as magnetized plasma (with “charged particles”) pushing into a weaker earth magnetic sheath due to the Interplanetary Magnetic Field (IMF) and Magnetic Sector Boundaries (MSBs) which bind earth and the sun “geo-magnetically” on weekly intervals. This has a direct and regular pressure gradient effect on earth’s climate while funneling in cloud-making particles. Nor was the long-known fact that direct changes in weather with these pressure-gradient flip flops pointed out. It was mentioned briefly in passing that TSI and its spectral imprint (e.g. radiation wavelengths of UV) effects earth’s climate. Both affect earth directly: the former creating clouds (albedo) and the later, traced to surface temperature fluctuations from 130 years ago to present in some mechanistic models – with 75{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} accuracy. That co-rotating particle-intermixing from leftover weaker solar flare blasts floats in the heliosphere, seeping into the earth’s sun-steered top atmospheric layer, is a concern for greater cloud-cover manufacture in weak-solar times – and so, precipitation and uneven cooling. UV in extremis (Extreme Ultra Violet [EvE]) radiation has 100 separate emitta; earth climate effects are known but extreme emitta has opened up a new door. With non-observable Energetic Emission Delays (EEDs) from SEPs time-lags (one year) not jibing with spectral flux, things get foggier still. These are for the most quite measurable negative sun-earth weather concerns in even “regular” solar cycles – those that studies glossed over here predict are coming in the near term. For it does not appear that a deep minimum is imminent. However, given both the paucity of accuracy in measurement and the cleanliness of accrued data modeled, certainty in what is coming will be much more apparent at Solar Cycle 25’s solar maximum – or, roughly at this cycle’s midpoint (2023-24). If the sunspot count is far less than 50 say, a grand minimum could be coming.
Is the sun solely responsible for earth climate and geomagnetic effects? The solar dynamo theory claims no sole earth-climate/electromagnetic-disturbance ownership. Other solar systemic and galactic/intergalactic forces could also contribute to earth climatic makeup or change or both. Purely internal geophysical earth factors (volcanic, earthquake, tectonic plate shift with earth-core released hot gas rise and effects on oceanic thermohaline currents etc.) and man-made effects to earth climate do occur. With improvements in quantifying observed phenomena apparent on all frontiers this picture will obtain sharper focus.
Steven Haywood Yaskell studied at Salem State University (Salem, Massachusetts USA) and Carleton University (Ottawa, Ontario Canada) and is an independent historical science researcher and writer. He has had research published by venues such as the Journal For the History and Heritage of Astronomy (JH2) at James Cook University (Australia) and World Scientific (The Maunder Minimum and the Variable Sun-earth Connection, with Wei-Hock Soon). The topic of this semi-academic essay was derived from his latest work, Grand Phases On The Sun: the case for a mechanism responsible for extended solar minima and maxima (Trafford:2012) based on the research of distinguished solar scientist Cornelis de Jager of the Netherlands (formerly of the Netherlands Institute for Space Research [SRON]). This essay was vetted by the eminent solar scientist Leif Svaalgard (formerly of Stanford University, California USA).
Notes
Herman, J.R. and Goldberg, R.A, Sun, Weather, and Climate (NASA Special Publication 426 [NASA sp;426] Scientific and Technical Information Branch) Washington, D.C. 1978, pp 76-77
Svaalgard, L, Solar Activity and the Weather, SUIPR Rpt. N0. 526, Institute for Plasma Research, Stanford University, Ca. 1973
Kirkby et al, “ Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation,” Nature, Vol 476, 25 August 2011, p. 429. This was the long-delayed and awaited CLOUD experiment planned by Danish investigator Henrik Svensmark. This was a climate chamber; a c. 120 inch-diameter stainless steel canister containing humid pure air, sulphuric acid (SO2) ozone (O3) and ammonia NH3 gas. Charged pion beams (that is, charged particle beams) were allowed to strike the canister. The behavior of the particles was then watched at various temperature levels. The cosmic rays changed the aerosol creation rate over a factor of 10.
Note Herman and Goldberg, pp 198-207. Some studies cited in these pages: Roberts, W. O. and Olsen, R.H, “New evidence for effects of variable solar corpuscular emission on the weather,” Rev Geophys Space Phys, 11(3). 731-40 (1973a); Roberts, W. O. and Olsen, R.H, “Geomagnetic storms and wintertime 300mb trough development in the North Pacific-North America area,” J Atmos Sci, 30, 135 (1973b); Wilcox J.M et al, “Solar magnetic structure: influence on stratospheric circulation,” Science 180 185-6 (1973a); Wilcox J.M et al, “Influence of solar magnetic sector structure on terrestrial atmospheric vorticity,” SUIPR Rpt. No. 530, Institute for Plasma Research, Stanford University , Ca. 1973b). Wilcox, J.M and Colburn, D.S, “Interplanetary sector structure at solar maximum,” J Geophys Res77, 751-56 Regarding gravitational and Rossby waves: King, J.W et al, “Large Amplitude Stationary Planetary Waves Induced In the Troposphere By the Sun,” J Atmos Terr Phys 39, 1357 (1977); Volland, H, “Periodic Variation Of the Solar Radiation – A Possible Source Of Solar Activity Weather Effects.” J Atmos Terr Phys 39, 69 (1977)
- Svensmark, M. B. Enghoff, N. J. Shaviv, J. Svensmark. “Increased ionization supports growth of aerosols into cloud condensation nuclei,” Nature Communications, 2017; 8
“Extreme UV (EUV) consists of 100 different emissions of UV radiation alone,” (Tom Woods, Subsystem Project Head (SDO EvE project summary [2010])
Cliver, E. W and Svalgaard, L, “The 1859 Solar–Terrestrial Disturbance and the Current Limits of Extreme Space Weather Activity,” Solar Physics (2004) 224: 407. See also Soon, W, and Yaskell, S.H, The Maunder Minimum and the Variable Sun-earth Connection (WSP:2003) pp 90-96.
de Jager, C and Duhau, S, “The Forthcoming Grand Minimum of Solar Activity,” J of Cosmology, Vol 8, 1983-1999 (2010) and de Jager, C and Duhau, S, “Sudden transitions and grand variations in the solar dynamo, past and future,” Volume 2, J Space Weather Space Clim (2012); Duhau, S. and de Jager, C. “On the origin of the bi-decadal and the semi-secular oscillations in the length of the day,” Geodesy for Planet Earth (2012).
Usoskin I. G, et al (2003 – blue line Figure 3a), Shove (1955 –points Figure 3a) and de Jager and Duhau (2010 – red lines Figure 3a)
Usoskin, I. G, et al, “Solar activity during the Holocene: the Hallstatt Cycle and its consequences for grand minima and maxima,” Astronomy & Astrophysics, Vol 587 (2016) for more recent data and explanations.
Steinhilber, F, et al, “Interplanetary magnetic fields during the past 9,300 years inferred from cosmogenic radionuclides,” J Geophys Res 115 A1, 2010
Carbon 14 (C14) traces solar activity in tree rings and ice cores c. 60,000 years back in isotopic decay measurement.
de Jager, C., Duhau, S., 2009, “Forecasting the parameters of sunspot cycle 24 and beyond,” J Atm Solar Terr Phys. 71, 239
de Jager et al, 2010. Magnetic-field phase diagrams are not described here for simplicity’s sake: the complication is at another level (Yaskell opinion).
Suess/De Vries: A C14-measured cycle not related to temperature that shows a sinusoidal curve, somewhat reliably describing long-term solar variability along that curve (minima and maxima) over long-term time. The Hallstatt: c. 2,300 years calculated using C14, Be10 etc. measure to hypothetically delineate earth’s orbit in deep time relative to the sun.
Hale: The magnetic c. 22-year (or double the Schwab) periodicity (17 – 32 years) (that is, 11 + 11 = 22 or one half of Hale = one Schwabe or vice versa). Gleissberg: Values of 34 + 68 + 72 = 174 or Lower Gleissberg are c. 5.8 years short of the solar inertial movement of Sun Solar System center of mass, or, the Barycenter Shift =179. 8 years.
Nagovitsyn, Y, (2005) Aamin is the minimums’ poloidal field strength (data of Mayaud, P.N, 1975, Nevanlinna, H and Katya, E, 1993 and Lockwood, W, 2009-2010)
Total solar irradiance (TSI) is defined as the amount of radiant energy emitted by the Sun over all wavelengths that fall each second on 11 sq ft (1 sq m) outside the earth’s atmosphere. Irradiance (is also) defined as the amount of electromagnetic energy incident on a surface per unit time per unit area. It has a spectral element to it called Spectral Solar Irradiance. (SSI) – in the spectral range of approximately 1-9 ft (0.30-3 m), where the shortest wavelengths are in the ultraviolet region of the spectrum, the intermediate wavelengths in the visible region, and the longer wavelengths are in the near infrared. Total means that the solar flux has been integrated over all wavelengths to include the contributions from ultraviolet, visible, and infrared radiation.
Yaskell, S.H, Grand Phases On The Sun: “The case for a mechanism responsible for extended solar minima and maxima” (Trafford:2012)
de Jager, C and Versteegh J.M, “Do Planetary Motions Drive Solar Variability?” Solar Physics (2005b) 229: pp 175–179. “Therefore they (exterior forces ) cannot significantly influence the solar dynamo unless a completely different hypothesis is forwarded that would, first, invalidate the present dynamo theory, and, secondly, at the same time explain solar activity, its polarity reversals and sunspots by planetary gravitational attractions.”
Maxima = toroidal field (Rmax). Minima = poloidal field (Aamin)
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