Extreme Space Weather Events 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

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

The Maunder minimum Eddy, Science, 1976 A period 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

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

Sunspot number: 11-year running means 5 Post 1750

Aurora e.g., Siscoe, Rev Geophys,

Cosmogenic isotope abundance Steinhilber et al., PNAS,

Heliospheric modulation potential Steinhilber et al., PNAS,

Climate records Manley, QJRMS, 1974, Lockwood et al., ERL, No “little ice age.”

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

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 |

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

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

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

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

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

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

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

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

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

Maunder minimum Owens, et al, GRL,

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

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

Streamer belt width Lockwood and Owens, JGR, Post 1750

Space weather “Great” geomagnetic storms, Greenwich observatory 25

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

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

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

PFSS solutions Magnetic field polarity at coronal source surface 29

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

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 Be  1/2 = 1.5×10 6 yr = atoms cm -2 s C & 10 Be: spallation products from O, N & Ar 14 C+0  14 C0 ; 14 C0+0H  14 C0 2 + H

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)

Space Challenges Central England Temperature (CET) Winter Means (DJF)  show upward drift  (linear) rate of rise dT ann /dt = 0.37  C c -1

Space Challenges Frost Fairs on the Thames  e.g. Winter 1683/4. Painted by Dutch artist Thomas Wijk ( )  N.B. notice how warm the next year was!

Space Challenges Frost Fairs on the Thames  The last one was 1813/14. Painted by Luke Clenell (1781 – 1840 )

Space Challenges Thames Freezing Over  N.B. in 1825 London Bridge demolished – acted as a salt water barrage  plus embankment increased flow rate

Space Challenges  1963 Thames at Windsor Thames Freezing Over