IV Reunión Española de Física Solar y Heliosférica
Presente y futuro: infraestructura observacional y explotación científica
Alcalá de Henares, 19-21 Jun 2013
Observaciones solares de
tiempos pretéritos: un reto para
la heliofísica de hoy
J. M. Vaquero
Centro Universitario de Mérida
Universidad de Extremadura, Spain
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3
Reasons Why the SSN Needs Reexamination
• It’s used… for important aplications:
– Long-term solar variability.
– Solar dynamo modeling.
– Climate change.
• We have two Sunspot Numbers.
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The ratio of the Group to Zurich SSN has two
significant discontinuities
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180
160
292
140
120
219
100
80
146
60
40
73
G ro u p S u n s p o t N u m b e r
N u m b e r o f d a y s w ith re c o rd s
365
20
0
1610
0
1635
1660
1685
1710
1735
1760
1785
1810
1835
1860
1885
1910
1935
1960
1985
Year
Vaquero (2007) Adv. Spa. Res. 40, 929.
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180
15
G ro u p S u n s p o t N u m b e r
160
1 633
1 7 th C e n tu ry
12
140
1 8 th C e n tu ry
18 00
1 9 th C e n tu ry
9
2 0 th C e n tu ry
120
1807
6
1652
100
3
80
0
16 17
0
fit
1 635
1634
5
10
15
20
25
30
35
1 741
60
1 793
1 792
40
1 782
1633
20
0
0
10
20
30
40
50
60
70
80
90
1 00
A c tive d a ys (% )
Vaquero et al. (2012) Solar Phys. 277, 389
Relationship between GSN and AD for all available data from Hoyt & Schatten (1998). The inset presents
an enlarged version but restricted to values AD < 35%.
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Vaquero et al. (2011) ApJL 731, L24.
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80
H o yt & S c h a tte n (1 9 9 8 )
G ro u p S u n s p o t N u m b e r
70
T h is ta lk
60
50
40
“Great Gap”
30
20
10
0
1730
1732
1734
1736
1738
1740
1742
1744
1746
1748
1750
Year
Vaquero & Trigo (2013), in progress
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Can we detect the solar cycle in the
Hoyt & Schatten Database?
•
•
Hoyt & Schatten Database is
contaminated with “zero” values of SN
derived from solar-astrometric
observations (solar altitude, solar
radius, …).
As an example, we can cite the
observations made with the great
meridian lines (camera obscura).
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Can we detect the solar cycle in the
Hoyt & Schatten Database?
I have designed a "new" database (extracted from HS98). The
purpose is to use only reliable observations to pinpoint AD and NAD.
I have only chosen (for each year) observers with recorded AD.
HS98
HS98 modified
64 Observers
36 Observers
19358 days with records
4141 days with records
402 Active days
402 Active days
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Can we detect the solar cycle in the
Hoyt & Schatten Database?
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
400
350
120
A c tiv e D a y s (% )
300
100
250
80
200
60
150
40
100
20
50
0
1645
N u m b e r o f d a y s w ith re c o rd s
140
0
1650
1655
1660
1665
1670
1675
1680
1685
1690
1695
1700
Year
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Can we detect the solar cycle in the
Hoyt & Schatten Database?
60
Max
Max?
A c tiv e D a y s (% )
50
Max
40
Max
30
20
10
min
min
min
min
min
0
1645
1650
1655
1660
1665
1670
1675
1680
1685
1690
1695
Year
Using a 5-year moving-average window and assuming a hyper-geometrical probability distribution…
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Some conclusions
• In the last few years, three major changes in H&S98 database have
been proposed:
– Onset of Maunder Minimum (Vaquero et al., 2011).
– Solar Cycle -1 (Vaquero et al., 2007; Vaquero & Trigo, 2013)
– Lost solar cycle (Usoskin et al., 2009; Zolotova & Ponyavin, 2011).
• There is interesting lost solar information that is preserved in
archives and libraries. We need a “Sunspot/Solar Historical Archive”.
• Maunder minimum was a period of very low sunspot numbers as
Hoyt & Schatten stated. However, their values probably are
understimated because they used astrometric observation records
(including camera obscura records!). Most likely, the solar cycle is
present in sunspot data.
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Observaciones solares de tiempos pretéritos: un reto para la