The bold NCAR prediction of an intense Solar Cycle 25 can easily be distinguished from the 10 other posted predictions, notably that of NOAA/SIDC’s panel of supposed experts, by near-term observation (fig.1) though not from early sunspot counts of 2021-22 (fig.2) nor toroidal oscillations (fig.3) — a decade of data will be needed to decisively determine the merits of the paired solar cycle proposal from SM McIntosh and colleagues.
Zharkova's lowball prediction, retracted by Nature's editor for cause, is not a contender but together with the NCAR high end scenario brackets the possibilities for total solar irradiance reaching the earth over the next 11 years. A high sunspot count could be significantly unfavorable to Arctic ice persistence.
The NCAR papers, while verbose and redundant, are easy to read: they do not contain any real physics (in the sense of solar magnetohydrodynamics) nor any actual math (outside of a dispensable Hilbert transform). The approach is entirely phenomenological — coordinated mapping of various data typets that extrapolate to a sunspot prediction number for Solar Cycle 25. That has significant implications for solar flare timing, astronaut safety, electric grid disruption, satellite damage, solar constant variation, Arctic Amplification and global warming.
The NCAR approach deprecates sunspot numbers as a mere end-product, proposing instead that associated 22-year Hale cycle observables are more fundamental. These include magnetic field polarity reversals, latitudinal distribution and migration extreme ultraviolet bright points, F10.7 radio flux, X-flares, extended cycle, g-nodes, magnetic multipole expansion, filament density, Fe XIV coronal green line emissions, Fe XII 195Å coronal scans, solar torsional oscillations, Wilcox solar polar field strength, collapse of the revised aa R27 index, Gleissberg modulation, and active region centroids that allow consistent wrapping of extended solar cycle terminators and pre-terminators.
These permit forecasting of the Solar Cycle 25 length, sunspot numbers, geomagnetic storms and earthbound increases in total solar irradiance. Success will provide strong physical guidance to interpretation of solar satellite imagery as well as to solar magnetohydrodynamic models that are not working yet. Only the Babcock-Leighton dynamo model is viable at this point.
There is important astrophysical carryover to a vast number of less easily observed sun-like stars via their Ca I spectrum. However little can be said about Solar Cycle 26 and beyond prior to the passage of SC 25 other than the NCAR approach would continue to apply.
Sunspots have a sorry history involving centuries of conspiracies, cranks, corporatist culprits (WUWT, Willie Soon), contrafactual nitrate enhancement in ice core layers, disputed increases in cloud nucleation, overstated global warming impacts relative to greenhouse gases and so on.
If we assume that key NCAR predictions come to pass, the next eleven years of rising solar ‘constant' implies more radiative energy reaching the top of the earth’s atmosphere and so more heat retained, thus supplementing rather larger greenhouse gas effects. Extreme ultraviolet could affect stratospheric ozone and so indirectly methane lifetime. Enhanced galactic cosmic rays also affect Be-10 and C-14 production and so dating of ice core layers, tree rings and permafrost deposits
Still, the envisioned 0.1% increase has significance for climate change and loss of Arctic sea ice, exacerbating the ongoing increased open water trend during melt season which has already attained 56% as a Siberian-side semi Blue Ocean Event (subsequent posts). The issue is mainly decreased surface albedo, meaning more energy absorption into sea water and less electromagnetic reflection back out to space, as discussed earlier in the K Pistone papers.
McIntosh and colleagues have provided a game-changing unification of centuries of daily solar data collection, rectifying forty years of community neglect of Wilson's original extended solar cycle:
"Once you identify the terminators in the historical records, the pattern becomes obvious. A weak Sunspot Cycle 25, as the community is predicting, would be a complete departure from everything that the data has shown us up to this point… As Cycle 25 rises in 2020, it will likely be the last solar activity cycle that is not fully understood.”
Twitter and research gate pages:
https://twitter.com/swmcintoshhttps://www.researchgate.net/profile/Scott_Mcintosh/publications 257 papers; 7417 citations
https://www.researchgate.net/profile/R_Leamon/researchhttps://earthsky.org/space/sunspot-cycle-25-among-strongest-on-record-says-ncar popular
https://twitter.com/hfsolar1 for current developments and animations
Below are open source links to 21 paper from the NCAR group, 16 oft-cited classics plus an explanatory glossary of sixty acronyms, technical terms and data sources commonly used. Links are also provided to satellite imagery display sites which can host spectacular displays. It’s convenient to list all the urls in chronological to and open all of them at once in web browser tabs using an open-all utility. Traditional astronomy does not use metric units (eg angstroms instead of nm) nor mainstream chemistry nomenclature (eg Ca XV roman numerals for Ca 14+ ions, not 15).
Acronyms and glossary:
-- TSI: total solar irradiance energy at top of earth's atmosphere, varies ~0.1% at 1361.5 W/m2
-- TOA: solar energy reaching top of earth’s atmosphere
-- SSN: sunspot number data set, Wolf number, ISN
-- SIDC: Solar Influences Data Center of Belgium Observatory official custodian of SSN sunspots
-- DRAO: Dominion Radio Astrophysical Observatory measures solar 10.7cm radio flux
-- SXI: Solar X-ray Imager satellites on GOES providing continuous coverage of solar corona
-- SOHO: Solar and Heliospheric Observatory
-- SDO: Solar Dynamics Observatory
-- MDI: Michelson Doppler Imager instrument on SOHO
-- HMI: Helioseismic and Magnetic Imager on 45s cadence SDO dopplergrams from Mar 2010 on
-- EIT: Extreme ultraviolet Imaging Telescope on SOHO resolution ∼2.6 arcmin per pixel
-- AIA: Atmospheric Imaging Assembly telescope on SDO at 94, 131, 171, 193, 195 211, 335 Å
-- CSA: Gnevysheva's Catalog of Solar Activity
-- Yohkoh: solar X-ray measurements from 19 91 until lost in Dec 2001
-- Lomnicky Stit observatory in Slovakia: slit observatory of coronal green line Fe XIV 530.3 nm
-- Schwabe cycle (1844): the 11-year sunspot cycle
-- Hale cycle (1919): 22-year magnetic activity cycle of two 11 year sunspot cycles
-- Gleissberg cycle (1939): 88-year trend in Hale cycle envelope
-- ESC: Wilson’s extended solar cycle of two interdigitated cycles of a Hale cycle
-- Hale's law: leading sunspots have opposite polarities in N/S hemispheres cycle to cycle
-- Joy's law: paired sunspot axes tilt with latitude per by coriolis force on flux rope
-- Spörer's law: steady decrease of sunspot latitude in the solar cycle forms butterfly diagram
-- Solar flare classes: log scale smallest are A-class, followed by B, C, M with X largest
-- Halloween Storm: extreme geomagnetic X-flare event in 2003 (solar cycle 23)
-- Carrington Event: extreme geomagnetic storm in Sept 1859 (solar cycle 10) severe CME
—Wolf minimum: 1280-1350
— Spoerer minimum: 1420–1540) first of the Grand Minima
-- Maunder minimum: low sunspot activity 1645-1715 weakly tied to Little Ice Age
— Dalton minimum: 1800–1830) third of the Grand Minima
-- Synodic Rotation: a solar rotation day as adjusted to perspective of earth observers
-- CR: synodic Carrington Rotation taken as 27.3 days varies with latitude, depth and time
-- F10.7: flux at wavelength of 10.7 cm peak observed solar radio emission, measured by DRAO
-- aa index: antipodal magnetic activity; high-aa index corresponds to geomagnetic storms
-- acv(27): index that track 27 day recurrence in aa with respect to extended solar cycle
-- R27: autocorrelation of consecutive 27-day aa-index sets of high speed solar wind structure
-- AR: NOAA catalogue of active regions AR 12673 of Sept 6 2017 notable X9.3 flare
-- XSM: extended solar minimum, distinct from Extended Solar Cycle (ESC)
-- CME: solar coronal mass ejection of a solar flare detected by overall light emission
-- EUV: extreme ultraviolet emission in sun’s corona, proxy for solar radiative output
-- BP: bright point, small region of extreme ultraviolet emission
-- BMRs: bipolar magnetic regions consisting of sunspot pairs of opposite magnetic polarity
-- g-nodes: largest convective scale of photospheric magnetic granules 100-250 mega-meters
-- CBP coronal bright point
-- CGL: coronal green line of Fe XIV atoms 530nm, Fe X 635nm) red, Ca XV569 nm) yellow
-- CRF: incoming anti-correlated galactic cosmic ray flux
-- PCF: polar crown filament highest latitude magnetic neutral line
-- PCP: polar cap potential pattern in ionosphere from solar wind and Earth's geomagnetic field
-- PCH: polar coronal holes dark (cooler) low density regions of the sun's outermost atmosphere
-- SCZ solar convection zone that resides above liquid-like solar core
-- RTTP: rush to the pole, rapid migration of high latitude magnetic flux to poles reversing polarity
-- HCS: Heliospheric Current Sheet surface of solar wind marking magnetic field reversal tilt angle
-- Plage: a bright region in the chromosphere near sunspots
-- CF: coronal filaments cool dark arcs of plasma imaged with H-alpha line at 65.6 nm
-- CH: coronal holes small regions where magnetic field lines are open and solar wind escapes
— GCR: galactic cosmic rays reach earth when solar wind knocks down earth’s magnetic field
— IMF: interplanetary magnetic field distinct from solar and earth’s
-- Prominences: identical to filaments but bright against contrasting dark background of space
-- Faculae: small bright spots of photosphere below plage strongly influencing on solar constant
-- Tachocline: sharp increase in solar rotation between convective and radiation zones of interior
-- Magnetic Buoyancy: flux tube generated by solar dynamo rising to the photosphere as sunspot
-- Toroidal and Poloidal: solar magnetic fields winding about latitudes and rotational poles. resp.
-- MHD: magnetohydrodynamic dynamo involving interacting plasma flows and magnetic fields
-- Solar Dynamo: magnetic field convection and differential rotation vs ohmic and diffusive decay
-- Babcock-Leighton dynamo (1961): driven by oscillation of toroidal and poloidal fields
-- Torsional Oscillations: migrating zones of slower and faster rotation in the sun’s atmosphere
NCAR publications:
The Sun’s magnetic Hale cycle and 27 day recurrences in the ‘aa' geomagnetic index
SC Chapman SW McIntosh RL Leamon NW Watkins
https://arxiv.org/pdf/2101.02569.pdf Jan 2021
Deciphering Solar Magnetic Activity. II. The Solar Cycle Clock and the Onset of Solar Minimum Conditions
RJ Leamon SW McIntosh SC Chapman NW Watkins A Chatterjee AM Title
https://arxiv.org/pdf/2012.15186.pdf Jan 2021
Deciphering Solar Magnetic Activity: 140 Years Of The Extended Solar Cycle Mapping the Hale Cycle
SW McIntosh RJ Leamon R Egeland M Dikpati RC Altrock D Banerjee S Chatterjee E Cliver AK Srivastava M Velli
https://arxiv.org/pdf/2010.06048.pdf Nov 2020a
Investigating the Chromospheric Footpoints of the Solar Wind
P Bryans SW McIntosh DH Brook B De Pontieu
Astrophysical Journal
https://iopscience.iop.org/article/10.3847/2041-8213/abce69 Dec 2020
Prediction of the In Situ Coronal Mass Ejection Rate for Solar Cycle 25: Implications for Parker Solar Probe In Situ Observations
C Möstl AJ Weiss … SW McIntosh et al
Astrophysical Journal 903(2)
https://iopscience.iop.org/article/10.3847/1538-4357/abb9a1/pdf Nov 2020
Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude
SW McIntosh SC Chapman RJ Leamon R Egeland NW Watkins
Solar Physics 295, 163
https://link.springer.com/article/10.1007/s11207-020-01723-y 2020b
Timing Terminators: Forecasting Sunspot Cycle 25 Onset
RJ Leamon SW McIntosh SC Chapman NW Watkins
Solar Physics 295, 36
https://arxiv.org/pdf/1909.06603.pdf 2020
Solar Wind Helium Abundance Heralds Solar Cycle Onset
BL Alterman JC Kasper RJLeamon SW McIntosh
https://arxiv.org/pdf/2006.04669.pdf Jun 2020
SC Chapman SW McIntosh RJ Leamon NW Watkins
Quantifying the solar cycle modulation of extreme space weather
Geophysics Research Letters
https://doi.org/10.1029/2020GL087795 May 2020
What the sudden death of solar cycles can tell us about the nature of the solar interior
SW McIntosh RJ Leamon R Egeland M Dikpati Y Fan M Rempel
Solar Physics 294(7), 88.
https://doi.org/10.1007/s11207-019-1474-y. 2019
Signature of Extended Solar Cycles as Detected from Ca ii K Synoptic Maps of Kodaikanal and Mount Wilson Observatory
S Chatterjee D Banerjee SW McIntosh RJ Leamon et al
https://iopscience.iop.org/article/10.3847/2041-8213/ab0e0e Mar 2019
Termination of Solar Cycles and Correlated Tropospheric Variability
RJ Leamon SW McIntosh DR Marsh
https://arxiv.org/pdf/1812.02692.pdf 2018
The Extended Solar Cycle: Muddying the Waters of Solar/Stellar Dynamo Modeling or Providing Crucial Observational Constraints?
AK Srivastava SW McIntosh et al
https://arxiv.org/abs/1807.07601 Jul 2018
Deciphering solar magnetic activity: Spotting solar cycle 25
SW McIntosh RJ Leamon
https://www.frontiersin.org/articles/10.3389/fspas.2017.00004/full 2017
The detection of Rossby-like waves on the Sun
SW McIntosh WJ Cramer MM Pichardo RJ Leamon
Nature Astronomy 1, 0086
https://search.proquest.com/openview/a47af4b881fe7a0cbace68131300396f/1?pq-origsite=gscholar&cbl=4669719 2017
The solar magnetic activity band interaction and instabilities that shape quasi-periodic variability
SW McIntosh RJ Leamon LD Krista AM Title et al
Nature Communications 6, 6491
https://www.nature.com/articles/ncomms7491.pdf 2015
Deciphering Solar Magnetic Activity. I. On the Relationship between the Sunspot Cycle and the Evolution of Small Magnetic Features
SW McIntosh X Wang RJ Leamon et al
Astrophys. J. 792, 12.
https://arxiv.org/pdf/1403.3071.pdf 2014a
Identifying Potential Markers of the Sun’s Giant Convective Scale
SW McIntosh X Wang RJ Leamon PH Scherrer
Astrophys. J. Lett. 784, L32
https://arxiv.org/pdf/1403.0692.pdf 2014b
Hemispheric Asymmetries of Solar Photospheric Magnetism: Radiative, Particulate, and Heliospheric Impacts
SW McIntosh RJ Leamon JB Gurman JP Olive et al
The Astrophysical Journal 765, 146
https://iopscience.iop.org/article/10.1088/0004-637X/765/2/146/meta 2013
Solar Cycle Variations in the Elemental Abundance of Helium and Fractionation of Iron in the Fast Solar Wind
SW McIntosh KK Kiefer RJ Leamon JC Kaspe ML Stevens
Astrophys. J. Lett. 740(1), L23.
https://arxiv.org/pdf/1109.1408.pdf 2011
Nine Years Of EUV Bright Points
SW McIntosh JB Gurman
Solar Phys. 228, 285.
https://www.researchgate.net/publication/226563954_Nine_years_of_EUV_bright_points 2005
Auxillary publications:
Living Reviews in Solar Physics
Various Authors, regular revisions
https://www.researchgate.net/journal/Living-Reviews-in-Solar-Physics-1614-4961DH Hathaway
Living Rev. Solar Phys., 12, 4
https://www.researchgate.net/publication/234373682_The_Solar_Cycle 2015
Forecasting long-term solar activity with time series models: Some cautionary findings
G Reikard
https://sci-hub.se/https://doi.org/10.1016/j.jastp.2020.105465 Dec 2020
Persistence of the Gleissberg 88‐year solar cycle over the last ∼12,000 years: Evidence from cosmogenic isotopes
AN Peristykh PE Damon
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2002JA009390 2003
The aa indices: A 100-Year Series Characterizing the Magnetic Activity
PN Mayaud
http://isgi.unistra.fr/Documents/References/Mayaud_JGR_1972.pdfRecurrent geomagnetic activity evidence for long-lived stability in solar wind structure
HH Sargent
J. Geophys. Res. 90, A2, 1425-1428
https://sci-hub.se/10.1029/ja090ia02p01425 1985
A revised 27 day recurrence index, arXiv:2101.02155
HH Sargent (forty-year update)
https://arxiv.org/pdf/2101.02155.pdf 2021
A Systematic Study of Hale and Anti-Hale Sunspot Physical Parameters
Jing Li
https://iopscience.iop.org/article/10.3847/1538-4357/aae31a Nov 2018
The Centennial Gleissberg Cycle and its association with extended minima
J Feynman A Ruzmaikin
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JA019478The Topology Of The Sun’s Magnetic Field And The 22-Year Cycle
HW Babcock
http://adsabs.harvard.edu/pdf/1961ApJ...133..572BOn the variation of solar coronal rotation using SDO/AIA observations
J Sharma, B Kumar AK Malik HO Vats
https://academic.oup.com/mnras/article/492/4/5391/5731421?login=trueComputing the Discrete-Time Analytic Signal via FFT
SL Marple IEEE
https://sci-hub.se/10.1109/78.782222 1999
Asymmetry in Solar Torsional Oscillation and the Sunspot Cycle
B Lekshmi D Nandy HM Antia
https://arxiv.org/pdf/1807.03588.pdf 2018
On the origin of solar torsional oscillations and extended solar cycle
VV Pipin AG Kosovichev
https://arxiv.org/pdf/1908.04525.pdf 2019
Prediction of the strength and timing of sunspot cycle 25 reveal decadal-scale space environmental conditions
P Bhowmik D Nandy
https://www.nature.com/articles/s41467-018-07690-0 What causes the inter-solar-cycle variation of total solar irradiance?
Nb Xiang and Df Kong
https://iopscience.iop.org/article/10.1088/0004-6256/150/6/171/meta 2015
Evolution of the Sun's Spectral Irradiance Since the Maunder Minimum
J Lean
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2000GL000043 2000
An Active Sun Throughout the Maunder Minimum
JBeer S Tobias NWeiss
https://link.springer.com/article/10.1023/A:1005026001784Hydromagnetic dynamo models
EN Parker
Astrophys. J. 122, 293 (1955)
http://adsabs.harvard.edu/full/1955ApJ...122..293POscillations of the baseline of solar magnetic field and solar irradiance on a millennial timescale
VV Zharkova, SJ Shepherd SI Zharkov E Popova
Scientific Reports 4336 (2020)
https://arxiv.org/abs/2002.06550 https://www.nature.com/articles/s41598-020-61020-3 retraction of Zharkova paper by editors
Data sources, imagery and explainers:
http://www.ngdc.noaa.gov/stp/space-weather/solar-data/solar-features/solar-flares/x-rays/goes/xrs/https://www.nasa.gov/mission_pages/sunearth/news/X-class-flares.htmlhttps://www.ngdc.noaa.gov/stp/solar/corona.htmlhttps://en.wikipedia.org/wiki/Solar_cycle_25 ten predictions largest is 225 from NCAR
https://en.wikipedia.org/wiki/Solar_cycle https://en.wikipedia.org/wiki/Solar_and_Heliospheric_Observatoryhttps://en.wikipedia.org/wiki/Magnetogramhttps://scied.ucar.edu/http://wso.stanford.edu/HCS.htmlhttps://iopscience.iop.org/article/10.3847/1538-4357/aaa4f4/pdfhttp://spaceweather.gc.ca/solarflux/sx-4-en.phphttp://www.ngdc.noaa.gov/stp/solar/corona.htmlhttp://solarscience.msfc.nasa.gov/greenwch.shtmlhttp://cosmicrays.oulu.fi/readme.htmlhttps://arxiv.org/pdf/1710.06545.pdfhttps://helioviewer.ias.u-psud.fr/ IASA Helioviewer
http://wso.stanford.edu/Tilts.html WSO tilt angle of the Heliospheric Current Sheet
http://www.sidc.be/silso/home SILSO daily total sunspot number from 1818
http://www.sidc.be/silso/cyclesmm Solar cycle maxima and minima
https://www.spaceweather.gc.ca/solarflux/sx-en.php Solar radio flux at 10.7 cm (F10.7 index) from 1947
http://isgi.unistra.fr/ aa index dataset from 1868
http://cosmicrays.oulu.fi/ GCR flux from 196
https://solarscience.msfc.nasa.gov/greenwch.shtml Greenwich Observatory-USAF/NOAA Sunspot areas 1874-2016