NASA: Sun undergoing a “deep solar minimum”

We don’t know what this means, but it might have substantial impact on Earth’s climate.  At the end are links for more information.

Deep Solar Minimum“, NASA, 1 April 2009 — Excerpt:

The sunspot cycle is behaving a little like the stock market. Just when you think it has hit bottom, it goes even lower. 2008 was a bear. There were no sunspots observed on 266 of the year’s 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days: plot. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008.

Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year’s 90 days (87%). It adds up to one inescapable conclusion:

  • “We’re experiencing a very deep solar minimum,” says solar physicist Dean Pesnell of the Goddard Space Flight Center.
  • “This is the quietest sun we’ve seen in almost a century,” agrees sunspot expert David Hathaway of the Marshall Space Flight Center.

Quiet suns come along every 11 years or so. It’s a natural part of the sunspot cycle, discovered by German astronomer Heinrich Schwabe in the mid-1800s. Sunspots are planet-sized islands of magnetism on the surface of the sun; they are sources of solar flares, coronal mass ejections and intense UV radiation. Plotting sunspot counts, Schwabe saw that peaks of solar activity were always followed by valleys of relative calm—a clockwork pattern that has held true for more than 200 years: plot.

The current solar minimum is part of that pattern. In fact, it’s right on time. “We’re due for a bit of quiet—and here it is,” says Pesnell. But is it supposed to be this quiet? In 2008, the sun set the following records:

  • A 55-year low in solar radio emissions …
  • A 50-year low in solar wind pressure …
  • A 12-year low in solar “irradiance” …

All these lows have sparked a debate about whether the ongoing minimum is “weird”, “extreme” or just an overdue “market correction” following a string of unusually intense solar maxima.

“Since the Space Age began in the 1950s, solar activity has been generally high,” notes Hathaway. “Five of the ten most intense solar cycles on record have occurred in the last 50 years. We’re just not used to this kind of deep calm.


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To read other articles about these things, see the FM reference page on the right side menu bar. Of esp relevance to this topic:

Some posts on the FM site about the solar cycle:

  1. Worrying about the Sun and climate change: cycle 24 is late, 10 July 2008
  2. Update: is Solar Cycle 24 late (a cooling cycle, with famines, etc)?, 15 july 2008
  3. Solar Cycle 24 is still late, perhaps signalling cool weather ahead, 2 September 2008
  4. Update on solar cycle 24 – and a possible period of global cooling, 1 October 2008
  5. This week’s report on the news in climate science, 7 December 2008
  6. Weekend reading recommenations about climate change, 13 December 2008
  7. An important new article about climate change, 29 December 2008
  8. My “wish list” for the climate sciences in 2009, 2 January 2009
  9. About the recent conference ”Solar Activity during the onset of Solar Cycle 24″, 3 January 2009

Articles about the sun and Earth’s climate, written for a broad audience:

  1. The Sun – Living With a Stormy Star“, National Geographic, July 2004 — Excellent introduction to our star.
  2. Ray of hope: Can the sun save us from global warming?“, The Independent, 5 December 2007 — “Could the Sun’s inactivity save us from global warming? David Whitehouse explains why solar disempower may be the key to combating climate change.”
  3. Sun’s Magnetic Field May Impact Weather And Climate: Sun Cycle Can Predict Rainfall Fluctuations“, ScienceDaily, 3 December 2008
  4. Danger ahead as the Sun goes quiet“, New Scientist, 7 January 2009

Articles about the sun and Earth’s climate, from the professional literature:

  1. “Variation of Cosmic Ray Flux and Global Cloud Coverage – a Missing Link in Solar-Climate Relationships”, Henrik Svensmark and Eigil Friis-Christensen, Journal of Atmospheric and Solar-Terrestrial Physics, 59 (11) (1997) 1225-1232.  See here
  2. “Influence of Cosmic Rays on Earth’s Climate”,  Henrik Svensmark, Physical Review Letters, 30 November 1998 – Volume 81, Issue 22, 1997, pp. 5027-5030 — See here.
  3. Variation of Cosmic Ray Flux and Global Cloud Coverage – a Missing Link in Solar-Climate Relationships“, Henrik Svensmark and Eigil Friis-Christensen, Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 59, pp. 1225-32, 1997
  4. “Reply to comments on ‘Variation of cosmic ray flux and global cloud coverage — a missing link in solar–climate relationships’”, Henrik Svensmark and Eigil-Friis-Christensen, Journal Of Atmospheric And Solar-terrestrial Physics Vol. 62 (1), pp. 79-80 — See here.
  5. Influence of Cosmic Rays on Earth’s Climate“, Henrik Svensmark, Physical Review Letters, Vol. 81, pp. 5027-30, 1998
  6. “Cosmic rays and Earth’s Climate”, Henrik Svensmark, Space Science Review 93: 155-166, 2000 – See here.
  7. Cosmic Rays, Clouds, and Climate“, Nigel Marsh and Henrik Svensmark, Space Science Review, Vol. 94, pp. 215-30, 2000
  8. Low Cloud Properties influenced by Cosmic Rays“, Nigel Marsh and Henrik Svensmark, Physical Review Letter, 4 December 2000, Volume 85, Issue 23, pp. 5004-5007.   See here.
  9. The Sun’s Chilly Impact on Earth“, Goddard Institute for Space Studies (NASA), 6 December 2001 — Press release for Shindell et al 2001 (see following entry)
  10. Solar forcing of regional climate change during the Maunder Minimum“, Shindell, D.T., G.A. Schmidt, M.E. Mann, D. Rind, and A. Waple, Science, 7 December 2001
  11. Cave air temperature response to climate and solar and geomagnetic activity“, P. Stoeva and A. Stoev, Memorie della Societa Astronomica Italiana, 2005
  12. “Empirical evidence for a nonlinear effect of galactic cosmic rays on clouds”, R. Giles Harrison and David B. Stephenson, Proceedings of the Royal Society, 8 April 2006 — AbstractPDF of article.
  13. The Antarctic Climate Anomaly Explained by Galactic Cosmic Rays“, Henrik Svensmark, arXiv, 14 December 2006
  14. Experimental Evidence for the Role of Ions in Particle Nucleation under Atmospheric Conditions“, Henrik Svensmark et al, Proceedings of the Royal Society A, Vol. 463, pp. 385-96, 2007
  15. Cosmoclimatology: a new theory emerges“, Henrik Svensmark, Astronomy and Geophysics, Royal Astronomical Society, London, Vol. 48, Issue 1, 2007
  16. The International Workshop “Solar Variability, Earth’s Climate and the Space Environment“, sponsored by NASA, held 1 – 6 June 2008 – See the abstracts of the papers presented.
  17. Global Climate Change: Is the Sun to blame?“, Sami K. Solanki, 3 June 2008 — From the June 2008 NASA conference.
  18. “Does a Spin-Orbit Coupling Between the Sun and the Jovian Planets Govern the Solar Cycle?”, I. R. G. Wilson A , C , B. D. Carter B and I. A. Waite B, Publications of the Astronomical Society of Australia, 26 June 2008 — Abstract.
  19. Solar activity and its influence on climate” C. de Jager (Royal Netherlands Institute for Sea Research),  Neatherlands Journal of Geosciences, October 2008
  20. Exploratory Analysis of Similarities in Solar Cycle Magnetic Phases with Southern Oscillation Index Fluctuations in Eastern Australia“, Robert G.V. Baker, Geographical Research, December 2008, Pages 380 – 398.
  21. “Solar Influence on Recurring Global, Decadal, Climate Cycles Recorded by Glacial Fluctuations, Ice Cores, Sea Surface Temperatures, and Historic Measurements Over the Past Millennium”, Don J. Easterbrook (Professor Emeritus in the Deptment of Geology at Western Washington U), the Fall meeting of  the American Geophysical Union, December 2008 — Abstract; discussion here.
  22. Is there a link between Earth’s magnetic field and low-latitude precipitation?“, Mads Faurschou Knudsen and Peter Riisager, Geology, January 2009
  23. “Sudden stratospheric warmings seen in MINOS deep underground muon data”, S. M. Osprey et al., Geophysical Research Letterrs, in press — See the press releasefrom the National Centre for Atmospheric Sciece for available details.
  24. ACRIM-gap and TSI trend issue resolved using a surface magnetic flux TSI proxy model“, Scafetta N., R. C. Willson, Geophysial Research Letters, 3 March 2009
  25. “GCR and ENSO trends in ISCCP-D2 low cloud properties”, Nigel Marsh and Henrik Svensmark, Journal of Geophysical Research , (In press) – See a preprint here.
  26. “Cosmic Rays, Clouds, and Climate “, Nigel Marsh and Henrik Svensmark, Space Science Review, (In press) — See a preprint here.

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