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Extreme Space Weather Events workshopm.j.owens@reading.ac.uk9 th June 2014 The Maunder minimum: An extreme space climate event? Mathew Owens, Mike Lockwood, Luke Barnard, Chris Scott and Ken McCracken The Maunder minimum: An extreme space climate event

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2 Overview Direct observations Sunspots Aurora Cosmogenic isotope abundance Climate observations Reconstructions Geomagnetic Sunspot Solar wind speed Space weather implications

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The Maunder minimum Eddy, Science, 1976 A period 1645-1715 with: An absence of sunspots An (apparent) reduction in auroral activity An (apparent) reduction in coronal structure during eclipses A reduction in 14 C, suggesting increased cosmic ray flux ( 10 Be is now known to have increased, though still cycled) 3

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Sunspot number Hoyt and Schatten, Sol Phys, 1998; Lessu et al, A&A, 2013; Svalgaard, IAU, 2011; Lockwood et al, JGR, 2014 4 Post 1750

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Sunspot number: 11-year running means 5 Post 1750

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Aurora e.g., Siscoe, Rev Geophys, 1980 6

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Cosmogenic isotope abundance Steinhilber et al., PNAS, 2011 7

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Heliospheric modulation potential Steinhilber et al., PNAS, 2011 8

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Climate records Manley, QJRMS, 1974, Lockwood et al., ERL, 2011 9 No little ice age.

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Open Solar Flux, F S Flux threading the coronal source surface Unsigned Flux, F U = |B R | r 2 cos( ) d d r = heliocentric distance B R = radial field = solar latitude = solar longitude + /2 2 - /2 0 closed field line open field lines

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Ulysses Balogh et al., 1995; Smith et al., 2001; Lockwood et al., 2000 ecliptic Ulysses showed that everywhere |B R |(d/R) 2 = |B RE | Thus total unsigned magnetic flux leaving the sun = 4 R 2 |B RE | |B RE | Earth R d |B R |

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Geomagnetic reconstructions Lockwood et al., JGR, 2014. See also Svalgaard & Cliver, JGR, 2010 12

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Relation of F S and V SW Lockwood & Owens, JGR, 2014 13

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Relation of F S and V SW Lockwood & Owens, ApJ, 2014; Cliver & Ling, Sol Phys, 2011 14

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Before 1845: F S from R Solanki et al., Nature, 2000; Owens & Crooker, JGR, 2006 F S can be modelled as a continuity equation dF S /dt = S L F S S ~ f CME ~ R 15

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Loss of F S Sheeley & Wang, ApJ, 2001; Owens et al., JGR, 2011 16

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F S loss and the HCS tilt Owens and Lockwood, JGR, 2012 17

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F S reconstruction Owens and Lockwood, JGR, 2012 18 F S sourceF S loss

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F S reconstruction Owens & Lockwood, JGR, 2012; Lockwood & Owens, JGR, 2014 19 Post 1750

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F S reconstruction (11-year) Owens & Lockwood, JGR, 2012; Lockwood & Owens, JGR, 2014 20 Post 1750

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Maunder minimum Owens, et al, GRL, 2012 21

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Modelling streamer belt width Schwadron et al., ApJ, 2010; Lockwood et al., JGR 2014 Separate streamer belt and coronal hole fluxes: F S = F SB + F CH L = L SB + L CH Assume: New flux is injected into the streamer belt Streamer belt flux eventually becomes coronal hole flux Two coupled equations: dF SB /dt = S - L SB F SB - S CH dF CH /dt = S CH - L CH F CH Streamer belt half width = sin -1 [1-F CH /F S ] 22

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Streamer belt width Owens et al., JGR 2014. See also Manoharan, JGR, 2010 23 M. Druckmuller

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Streamer belt width Lockwood and Owens, JGR, 2014 24 Post 1750

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Space weather Great geomagnetic storms, Greenwich observatory 25

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Maunder minimum summary Extremely low (long term) solar magnetic field, compared to sunspot era and the last 10,000 years Increased occurrence of cold winters, but no little ice age Reduced auroral frequency, Difficult to quantify if this was extreme Polarity of the solar field continued to cycle Coronal holes were extremely small and the streamer belt was extremely broad Slow solar wind at Earth. No/weak CIRs? Continued CME activity? 26

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HCS location e.g., Smith el al., 2003; Owens & Forsyth, LRSP, 2013 27

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Computing the F S loss rate Owens and Lockwood, JGR, 2012 28

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PFSS solutions Magnetic field polarity at coronal source surface 29

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Three-dimensional structure of interplanetary magnetic field Owens et al., JGR, 2011 30

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OCEANS STRATOSPHERE ( 2/3) GALACTIC COSMIC RAYS BIOMASS TROPOSPHERE ( 1/3) ICE SHEETS 10 Be + AEROSOL ( ~1 year) ( ~1 week) 14 C 1/2 = 5370 yr = 2 atoms cm -2 s -1 10 Be 1/2 = 1.510 6 yr = 0.018 atoms cm -2 s -1 14 C & 10 Be: spallation products from O, N & Ar 14 C+0 14 C0 ; 14 C0+0H 14 C0 2 + H

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ERA-40 Analysis of DJF temperatures & circulation (difference of high and low tercile subsets) sorted using open solar flux F S Low solar activity gives lower surface temperatures in central England Effect much stronger in central Europe Analysis shows a distinct system to NAO (Woollings et al, GRL.,2010; see also Barriopedro et al., JGR, 2008)

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Space Challenges 2012m.j.owens@reading.ac.uk Central England Temperature (CET) Winter Means (DJF) show upward drift (linear) rate of rise dT ann /dt = 0.37 C c -1

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Space Challenges 2012m.j.owens@reading.ac.uk Frost Fairs on the Thames e.g. Winter 1683/4. Painted by Dutch artist Thomas Wijk (1616-1677) N.B. notice how warm the next year was!

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Space Challenges 2012m.j.owens@reading.ac.uk Frost Fairs on the Thames The last one was 1813/14. Painted by Luke Clenell (1781 1840 )

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Space Challenges 2012m.j.owens@reading.ac.uk Thames Freezing Over N.B. in 1825 London Bridge demolished acted as a salt water barrage plus embankment increased flow rate

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Space Challenges 2012m.j.owens@reading.ac.uk 1963 Thames at Windsor Thames Freezing Over