long-term solar activity reconstruction: grand … solar activity reconstruction: grand minima and...
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Long-Term Solar Activity Reconstruction:
Grand Minima and Maxima
Ilya Usoskin1, Sami K. Solanki2, Gennady Kovaltsov3
1 Sodankylä Geophysical Observatory, University of Oulu, Finland2 Max-Planck-Institut for Solar System Research, Katlenburg-Lindau, Germany
3 Ioffe Physical-Technical Institute, St.Petersburg, Russia
Solar activity variations: telescopic sunspot number record
• 11-year solar cycle (Christian Horrebow 1770s; Schwabe 1843)
• Variable amplitude/envelope (Gleissberg 1944);• Maunder minimum (Hivelius; Eddy 1976);• The contemporary level is high
0
50
100
150
1600 1700 1800 1900 2000
Gro
up s
unsp
ot n
umbe
r
Solar activity in the past
1E+01E+11E+21E+31E+41E+51E+6
Years before present
Electronic
Photographic data
Sunspot counts and drawings
Aurora sightings
Naked eye sunspot observations
Cosmogenic isotopes
Geomagnetic measurements
Proxy of SA: Cosmogenic isotopes
IMF, solar wind Cosmic Rays
Geomagneticfield
• Variable solar activity expands to the Heliosphere: solar wind, interplanetary magnetic field, interplanetary transients (CME, corotation regions), etc.• Galactic cosmic rays are modulated by IMF, magnetic inhomogeneities, solar wind;• Geomagnetic field partly shields the Earth (mid- and low-latitude regions) from incoming cosmic rays;• This process is well understood and can be properly modelled (Beer, Space Sci. Rev.,
2000; Usoskin et al., Phys. Rev. Lett., 2003; Solanki et al., Nature, 2004)
SN reconstruction from 14C or 10BeSunspot numbersSunspot numbers
e.g.e.g. ModelModel by Solanki by Solanki et al. et al. (2002)(2002)
SunspotSunspot number number open open magnmagn.. fluxflux
Heliospheric paramsHeliospheric params
e.g.e.g. ModelModel by by Usoskin et al. (Usoskin et al. (2002a)2002a)
ModulModul. strength . strength CR CR intensintens. variations. variationsCR intensityCR intensity
Deposition models, Deposition models, paleomagneticpaleomagnetic modelsmodels1010Be:Be: Webber & Higbie, Webber & Higbie, 1414C: C: UsoskinUsoskin & & KromerKromerBB⊕⊕::YangYang et al. (2000), et al. (2000), KorteKorte & Constable (2005)& Constable (2005)
CosmogenicCosmogenic isotopes isotopes UsoskinUsoskin et al. (2002b)et al. (2002b) in natural archivesin natural archivesSolanki et al. (2004) , Solanki et al. (2004) , UsoskinUsoskin et al. (2004, 2007) et al. (2004, 2007)
nonlinearnonlinear
nonlinearnonlinear
Sunspot number reconstructed from 14C
0
20
40
60
80
-10000 -9000 -8000 -7000 -6000 -5000 -4000
Sun
spot
num
ber
0
20
40
60
80
-4000 -3000 -2000 -1000 0 1000 2000
Years (-BC/AD)
Sun
spot
num
ber
Smoothed Sunspot number over 11400 yr
27 Grand minima19 Grand maximacan be identified.
Minima cover1880 yr ≈ 17% of timeMaxima cover1030 yr ≈ 9% of time
Solanki,. Usoskin, Kromer, Schüssler, Beer, Nature, 2004 Usoskin, Solanki & Kovaltsov, A&A, 2007
Sunspot number statistics
0 20 40 60 80 100
1
10
100
Max
Num
ber
per
bin
<Sunspot number>
Min
Red curve: best-fit normal distribution
Waiting time distribution
100 1000
1E-4
1E-3
Diff
eren
tial d
istr
ibut
ion
Interval length (Years)100 1000
1E-4
1E-3
0.01
wai
ting
time
dist
ribut
ion
Interval length (Years)
Grand minima Grand maxima
Closer to power law (red lines) than to exponential (dotted yellow lines) � waiting time tends to show clustering of Min and Max
Durations of Minima & Maxima
50 100 1500
2
4
6
Num
ber
per
bin
Duration (Years)
0 50 100 150 200
1E-3
0.01
Diff
eren
tial d
istr
ibut
ion
Duration (Years)
Grand minima Grand maxima
Maunder Spoerer
Quasi-Bimodal Exponential
Conclusions
�� The Sun spends 17% of the time in The Sun spends 17% of the time in grand minimagrand minima, 9% in , 9% in grand grand maximamaxima. Currently the Sun is in a grand maximum.. Currently the Sun is in a grand maximum.
�� Grand Grand minimaminima//maximamaxima are not due to longare not due to long--term cyclic variations term cyclic variations but rather to stochastic/chaotic processes. but rather to stochastic/chaotic processes.
�� Waiting time distribution of occurrence of Waiting time distribution of occurrence of grand minimagrand minima and and maximamaxima deviates from an exponential distribution deviates from an exponential distribution �� typical of typical of nonnon--Poisson processes with, e.g., selfPoisson processes with, e.g., self--organized criticality or organized criticality or processes related to accumulation and release of energy.processes related to accumulation and release of energy.
�� Grand minimaGrand minima can be classified into two different types: short can be classified into two different types: short minima of minima of Maunder typeMaunder type and long minima of and long minima of SpSpöörerrer typetype..
�� Duration of Duration of grand maximagrand maxima exponentially distributed exponentially distributed �� leaving a leaving a grand maximumgrand maximum is a random process, unlike for is a random process, unlike for grand minimagrand minima
Ti-44 activity:
measure-ments vs.
model
95%95%4.4 (11)4.4 (11)M05M05--AA
4%4%20.5 (11)20.5 (11)M05M05--MM
97%97%2.44 (8)2.44 (8)S04S04
98%98%7.55(17)7.55(17)GSNGSN
Confid. levelConfid. levelχχ2 2 (DoF)(DoF)ModelModel
3
4
5
6
7
8
9
1750 1800 1850 1900 1950 2000
44Ti a
ctiv
ity (dpm
/kg) GSN
S04
M05-A
M05-M
Ti-44
/kg
)
Preliminary Preliminary results!results!
New data are New data are currently being currently being finalized and finalized and
analyzedanalyzed
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