Mike Lockwood (Southampton University & Space Science and Technology Department, STFC/Rutherford Appleton Laboratory ) Open solar flux and irradiance during the current “exceptional” solar minimum: implications for climate change MIST/UKSP Session, RAS/NAM - EAS/JENAM, UoH, 22 April 2009

Recent Data ► radial IMF, |B r | ► sunspot number, R ► Kp geomagnetic index ► PMOD composite of TSI

Recent Data ► radial IMF, |B r | ► sunspot number, R ► Kp geomagnetic index ► PMOD composite of TSI Space Age Data

The “Ulysses Result” ecliptic B r (r 1 ) r1r1 r |B r | Balogh et al., 1995; Lockwood et al., 1999; 2004 Smith et al., 2001 Lockwood and Owens (2009) & Lockwood et al. (2004) show that use of this equation is accurate to within  2.5% Thus total signed magnetic flux threading r 1 = 1AU is F S (r 1 ) = (1/2)  4  r 1 2 CR Ulysses showed that |B r (r)| (r/r 1 ) 2 = |B r (r 1 )|

Open Solar Flux from IMF data ( Lockwood, Rouillard and Finch 2009 ) Open Solar Flux, F S (10 14 Wb)  F S (r 1 ) ► using the Ulysses result of the invariance of the radial IMF, B r & hourly mean data ► accurate to  2.5%

Open Solar Flux ecliptic Coronal Source Surface quantified by PFSS from solar magnetograms B r (r 1 ) r1r1 r |B r | Balogh et al., 1995; Lockwood et al., 1999; Smith et al., 2001 total (“open”) magnetic flux leaving the sun, F S (r o ) = (1/2)x4  2 r o 2 CR “excess”, F S (r)  F S (r o ) > 0 roro

Kinematic Excess Flux Correction ( Owens et al. 2008, Lockwood et al. 2009) ► excess flux,  F S (r) = 2  r 2 |B r (r)|  2  r 1 2 |B r (r 1 )| ► r o = 2.5R  ► PFSS values from photospheric magnetograms  F S (r 1 ) = 0  F S (r o ), from PFSS

Open Solar Flux from IMF data ( Lockwood, Rouillard and Finch 2009 ) Open Solar Flux, F S (10 14 Wb)  ► kinematic correction for effect of longitudinal solar wind structure,  F S (r o ) ► makes results consistent with PFSS ( Lockwood et al., 2009 ) F S (r o ) = F S (r 1 )   F S (r o ) [ F S (r o ) ] PFSS F S (r 1 )

► sunspot number, R ► open solar flux F S ► GCR counts C ► observations of TSI ► solar cycle length, L running mean over T=[9:(1/4):13] yrs running mean over T=L yrs ► global mean temperature The current minimum follows from recent trends. ( Lockwood and Fröhlich, 2007 )

Millennial Variation  composite 25-year means) from cosmogenic isotopes 14 C & 10 Be by Steinhilber et al. (2008) Year AD  Solar Modulation Parameter,  (MV)  composite from S olanki et al., 2004; Vonmoos et al., 2006 & Muscheler et al., 2007 we are still within recent grand maximum

 show the present minimum 23/24 is close to minima 19/20 and 16/17  earlier minima are lower Cenntennial Variations - Geomagnetic Activity Indices

Geomagnetic activity annual means: correlations with solar wind & IMF  the corrected aa index is a range index & correlates best with B IMF V SW 2  the median index m is from hourly mean data & correlates best with B IMF V SW 0.3  aa C  m r aa = 0.97 S r > % (AR-1 noise) r m = 0.89 S r = % (AR-1 noise)

Centennial Variations geomagnetic activity  the different dependences of aa C and m on V SW are significant at the 87% level. 0.87

Centennial Variations: reconstructed solar wind, IMF & open flux  use correlations to extrapolate V SW, B IMF & F S annual means back to 1905

Centennial Variations: the rise and fall of the current grand maximum  solar cycle running means Abreu et al. (2008)  defining grand max. by  > 600 MV it began in 1920  linear extrapolation gives end dates consistent with GSM durations

Has The Temperature Rise at Earth’s Surface Stalled in Recent Years?  Global Mean Air Surface Temperature (GMAST) composite from CRU, UEA HadCRUR3v

 /2  time constant used to smooth data  = 10 years Has The Temperature Rise at Earth’s Surface Stalled in Recent Years?  3 example trends for the last  /2 years:  2  per 100yr 0  per 100yr +2  per 100yr

Variations about the trend   = 10 yr  for the last  /2 years:  2  per 100yr

Variations about the trend   = 10 yr  for the last  /2 years: 0  per 100yr

Variations about the trend   = 10 yr  for the last  /2 years: +2  per 100yr

Compare to the distribution of past variations about the trend  Distribution of deviations over  /2 yrs   = 10 yrs  3 example trends for the last  /2 years:  2  per 100yr 0  per 100yr +2  per 100yr  = 10 yrs =   x = 0.034

Recent (last  /2 yrs) fluctuations pdf:-

Recent (last  /2 yrs) fluctuations are consistent with past ones around a trend of +2  c -1  For  = 6 yr recent trend is most probably  -2  c -1 (but could be up to  +4  c -1 )  For  > 10 yr trend is most likely > 0  For  > 18 trend  +2  c -1

the present solar minimum is uniquely low - for the space age ► the present solar minimum is uniquely low - for the space age cosmogenic isotopes show that the space age thus far has been a grand solar maximum (GSM) ► cosmogenic isotopes show that the space age thus far has been a grand solar maximum (GSM) geomagnetic activity data and the statistics of GSM durations both indicate that the present low minimum is consistent with the end of the current GSM ► geomagnetic activity data and the statistics of GSM durations both indicate that the present low minimum is consistent with the end of the current GSM the levelling off of global mean air surface temperatures is consistent with previous fluctuations about the upward trend ► the levelling off of global mean air surface temperatures is consistent with previous fluctuations about the upward trend