Sun 201811

With many thanks to NASA Solar Dynamics Observatory and European Space Agency PROBA Teams.

Earlier on Sun events:
https://herrero-radio-astronomy.blogspot.com/2018/03/sun-earth-jupiter-20180330.html

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About the evolution of the Sun active regions

As the days go by, I frequently show details of active region magnetograms images and charts, and other data, for active regions I think may be suspect of initiating the radio events we study.

I started studying solar radio emission in 1966, I am not finished yet :)

The degree of activity frequently varies much from day to day and is a complex subject studied for many decades.

Lidia van Driel-Gesztelyi and Lucie May Green have published last month a "Living Review of Solar Physics" titled:

"Evolution of Active Regions" , 98 pages, including 17 pages of references, free to download at:

http://solarphysics.livingreviews.org/Articles/lrsp-2015-1/

http://solarphysics.livingreviews.org/Articles/lrsp-2015-1/download/lrsp-2015-1Color.pdf

Section 6 studies the case of AR 7978, "...subjected to the most comprehensive analysis of any AR..." as it evolved over a 6 month period.

Appendix A is a very good summary of Sunspot classifications, including the McIntosh and Hale methods.

I leave you repeating their quote from a poem by Laszlo Detre :

“  A Solar Physicist’s Lament  ....

It looks as if many a sunny day
Will pass along on its way
Before we solve it all...  "

My ignorance is vast
Have a wonderful day
Victor :)

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Solar Dynamics Observatory - Now and Daily - Images Movies
http://sdo.gsfc.nasa.gov/data/
Solar Type Examples
http://herrero-radio-astronomy.blogspot.com/2015/07/solar-type-examples.html
Comparison of Cycles 23 and 24 sunspot and coronal mass ejection numbers
http://3.bp.blogspot.com/-MxC1nf6CLuU/VcD2X3QT_kI/AAAAAAAALyg/n15qgyvN81g/s1600/W150804%2B50.png
http://sidc.oma.be/cactus/ CACTUS page
Introductory Radio Astronomy references
http://herrero-radio-astronomy.blogspot.com/2015/06/introductory-radio-astronomy-references.html?m=1
My recent event posts by month:
http://herrero-radio-astronomy.blogspot.com/2015/10/sun-earth-jupiter-20151001.html
http://herrero-radio-astronomy.blogspot.com/2015/09/sun-earth-jupiter-20150916.html
http://herrero-radio-astronomy.blogspot.com/2015/09/sun-earth-jupiter-2015-september.html
http://herrero-radio-astronomy.blogspot.com/2015/08/sun-earth-jupiter-2015-august.html
http://herrero-radio-astronomy.blogspot.com/2015/07/sun-earth-jupiter-2015-july.html
http://herrero-radio-astronomy.blogspot.com/2015/06/sun-earth-jupiter-2015-june.html
Links to earlier posts by month:
http://herrero-radio-astronomy.blogspot.com/2015/08/links-to-monthly-sun-earth-jupiter-posts.html?m=1
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Diminishing solar activity may bring new Ice Age by 2030

"...The arrival of intense cold similar to the one that raged during the “Little Ice Age”, which froze the world during the 17th century and in the beginning of the 18th century, is expected in the years 2030—2040. These conclusions were presented by Professor V. Zharkova (Northumbria University) during the National Astronomy Meeting in Llandudno in Wales by the international group of scientists, which also includes Dr Helen Popova of the Skobeltsyn Institute of Nuclear Physics and of the Faculty of Physics of the Lomonosov Moscow State University, Professor Simon Shepherd of Bradford University and Dr Sergei Zharkov of Hull University..."

"...In the current study published in 3 peer-reviewed papers the researchers analysed a total background magnetic field from full disk magnetograms for three cycles of solar activity (21-23) by applying the so-called “principal component analysis”, which allows to reduce the data dimensionality and noise and to identify waves with the largest contribution to the observational data. This method can be compared with the decomposition of white light on the rainbow prism detecting the waves of different frequencies. As a result, the researchers developed a new method of analysis, which helped to uncover that the magnetic waves in the Sun are generated in pairs, with the main pair covering 40% of variance of the data (Zharkova et al, 2012, MNRAS). The principal component pair is responsible for the variations of a dipole field of the Sun, which is changing its polarity from pole to pole during 11-year solar activity..."

http://astronomynow.com/2015/07/17/diminishing-solar-activity-may-bring-new-ice-age-by-2030/

 

Royal Astronomical Society National Astronomy Meeting 2015 Llandudno Wales :

http://nam2015.org/

http://nam2015.org/index.php/science-programme/parallel-sessions/list/2

Lockwood 2013: "Reconstruction and Prediction of Variations in the Open Solar Magnetic Flux and Interplanetary Conditions"

I refer to Lockwood 2013: "Reconstruction and Prediction of Variations in the Open Solar Magnetic Flux and Interplanetary Conditions"
http://adsabs.harvard.edu/abs/2013LRSP...10....4L

Abstract: "Historic geomagnetic activity observations have been used to reveal centennial variations in the open solar flux and the near-Earth heliospheric conditions (the interplanetary magnetic field and the solar wind speed). The various methods are in very good agreement for the past 135 years when there were sufficient reliable magnetic observatories in operation to eliminate problems due to site-specific errors and calibration drifts. This review underlines the physical principles that allow these reconstructions to be made, as well as the details of the various algorithms employed and the results obtained. Discussion is included of: the importance of the averaging timescale; the key differences between ``range'' and ``interdiurnal variability'' geomagnetic data; the need to distinguish source field sector structure from heliospherically-imposed field structure; the importance of ensuring that regressions used are statistically robust; and uncertainty analysis. The reconstructions are exceedingly useful as they provide calibration between the in-situ spacecraft measurements from the past five decades and the millennial records of heliospheric behaviour deduced from measured abundances of cosmogenic radionuclides found in terrestrial reservoirs. Continuity of open solar flux, using sunspot number to quantify the emergence rate, is the basis of a number of models that have been very successful in reproducing the variation derived from geomagnetic activity. These models allow us to extend the reconstructions back to before the development of the magnetometer and to cover the Maunder minimum. Allied to the radionuclide data, the models are revealing much about how the Sun and heliosphere behaved outside of grand solar maxima and are providing a means of predicting how solar activity is likely to evolve now that the recent grand maximum (that had prevailed throughout the space age) has come to an end."

Edmonds 2013: "The correlation of 27 day period solar activity and daily maximum temperature in continental Australia"

I refer to Edmonds 2013: "The correlation of 27 day period solar activity and daily maximum temperature in continental Australia"
http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1307.0921

Abstract: "We report the first observation of a 27 day period component in daily maximum temperature recorded at widely spaced locations in Australia. The 27 day component, extracted by band pass filtering, is correlated with the variation of daily solar radio flux during years close to solar minimum. We demonstrate that the correlation is related to the emergence of regions of solar activity on the Sun separated, temporally, from the emergence of other active regions. In this situation, which occurs only near solar minimum, the observed 27 day variation of temperature can be in phase or out of phase with the 27 day variation of solar activity. During solar maximum correlation of temperature and solar activity is much less defined. The amplitude of the 27 day temperature response to solar activity is large, at times as high as 6 degrees C, and much larger than the well documented temperature response to the 11 year cycle of solar activity. We demonstrate that the 27 day temperature response is localised to the Australian continent and increases towards the centre of the continent. Several aspects of the 27 day temperature response are consistent with a 27 day period solar input to the Earth continents generating large scale planetary waves."

Sun 140108, Solar Cycle Progression

For more posts on the Solar Cycle Progression see:
http://herrero-radio-astronomy.blogspot.com/search/label/Solar%20Cycle%20Progression

Owens and Forsyth 2013: The Heliospheric Magnetic Field

I refer to Owens and Forsyth 2013:
"The Heliospheric Magnetic Field"
http://adsabs.harvard.edu/abs/2013LRSP...10....5O

Abstract:
"The heliospheric magnetic field (HMF) is the extension of the coronal magnetic field carried out into the solar system by the solar wind. It is the means by which the Sun interacts with planetary magnetospheres and channels charged particles propagating through the heliosphere. As the HMF remains rooted at the solar photosphere as the Sun rotates, the large-scale HMF traces out an Archimedean spiral. This pattern is distorted by the interaction of fast and slow solar wind streams, as well as the interplanetary manifestations of transient solar eruptions called coronal mass ejections. On the smaller scale, the HMF exhibits an array of waves, discontinuities, and turbulence, which give hints to the solar wind formation process. This review aims to summarise observations and theory of the small- and large-scale structure of the HMF. Solar-cycle and cycle-to-cycle evolution of the HMF is discussed in terms of recent spacecraft observations and pre-spaceage proxies for the HMF in geomagnetic and galactic cosmic ray records."

Prediction for Solar Cycle 24 polar magnetic field reversal

I refer to Upton and Hathaway 2013, "Predicting the Sun's Polar Magnetic Fields with a Surface Flux Transport Model" :
http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1311.0844

Abstract: "The Sun's polar magnetic fields are directly related to solar cycle variability. The strength of the polar fields at the start (minimum) of a cycle determine the subsequent amplitude of that cycle. In addition, the polar field reversals at cycle maximum alter the propagation of galactic cosmic rays throughout the heliosphere in fundamental ways. We describe a surface magnetic flux transport model that advects the magnetic flux emerging in active regions (sunspots) using detailed observations of the near-surface flows that transport the magnetic elements. These flows include the axisymmetric differential rotation and meridional flow and the non-axisymmetric cellular convective flows (supergranules) all of which vary in time in the model as indicated by direct observations. We use this model with data assimilated from full-disk magnetograms to produce full surface maps of the Sun's magnetic field at 15-minute intervals from 1996 May to 2013 July (all of sunspot cycle 23 and the rise to maximum of cycle 24). We tested the predictability of this model using these maps as initial conditions, but with daily sunspot area data used to give the sources of new magnetic flux. We find that the strength of the polar fields at cycle minimum and the polar field reversals at cycle maximum can be reliably predicted up to three years in advance. We include a prediction for the cycle 24 polar field reversal."

Third Solar Sunspot Number Workshop - Tucson January 2013

Many thanks to Dr. Salvador Aguirre for correspondence on this topic, his Blog:
http://drsaguirremexico.blogspot.com/

Very interesting presentation slides at:
http://ssnworkshop.wikia.com/wiki/Presentations_3

Dr. Leif Svalgaard Research Page:
http://www.leif.org/research/

AAVSO Solar Section:
http://www.aavso.org/solar
http://www.aavso.org/solar-bulletin


 


 

No sunspots after 2017 ??

I refer to Penn and Livingston 2010:
"Long-term Evolution of Sunspot Magnetic Fields"

http://arxiv.org/abs/1009.0784v1 

 From the abstract:
"...Independent of the normal solar cycle, a decrease in the sunspot magnetic field strength has been observed using the Zeeman-split 1564.8nm Fe I spectral line at the NSO Kitt Peak McMath-Pierce telescope. Corresponding changes in sunspot brightness and the strength of molecular absorption lines were also seen. This trend was seen to continue in observations of the first sunspots of the new solar Cycle 24, and extrapolating a linear fit to this trend would lead to only half the number of spots in Cycle 24 compared to Cycle 23, and imply virtually no sunspots in Cycle 25..."

13 citations to this paper at:

http://adsabs.harvard.edu/cgi-bin/nph-ref_query?bibcode=2011IAUS..273..126P&refs=CITATIONS&db_key=AST 

NOAA Space Weather Prediction Center lists ONE event on 130124 !! :

http://www.swpc.noaa.gov/ftpdir/indices/events/20130124events.txt 

So far, the maximum monthly average sunspot number for cycle 24 occurred in November 2011: http://www.swpc.noaa.gov/SolarCycle/sunspot.gif

Solar cycle progression - November 2012

I refer to the NOAA Space Weather Prediction Center "Solar Cycle Progression" report :

http://www.swpc.noaa.gov/SolarCycle/

 "...the panel has agreed that solar minimum occurred in December, 2008... Given the predicted date of solar minimum and the predicted maximum intensity, solar maximum is now expected to occur in May, 2013. Note, this is a consensus opinion, not a unanimous decision. A supermajority of the panel did agree to this prediction."

 The maximum Sunspot Number Monthly Value for Cycle 24 MAY have already occurred in October 2011, with a value of about 95.

Solar Cycle Progression