Revisiting the Sunspot Number A 400-Year Perspective on the Solar Cycle

被引:506
作者
Clette, Frederic [1 ]
Svalgaard, Leif [2 ]
Vaquero, Jose M. [3 ]
Cliver, Edward W. [4 ]
机构
[1] Observ Royal Belgique, World Data Ctr SILSO, B-1180 Brussels, Belgium
[2] Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA
[3] Univ Extremadura, Dept Fis, Merida, Spain
[4] Natl Solar Observ, Sunspot, NM 88349 USA
关键词
Sun; Sunspots; Sunspot Number; Solar cycle; Solar activity; KINEMATIC DYNAMO MODELS; LONG-TERM VARIATIONS; TOTAL IRRADIANCE; MAUNDER MINIMUM; MAGNETIC-FLUX; RECONSTRUCTION; INDEX; SUN; RELIABILITY; VALUES;
D O I
10.1007/s11214-014-0074-2
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Our knowledge of the long-term evolution of solar activity and of its primary modulation, the 11-year cycle, largely depends on a single direct observational record: the visual sunspot counts that retrace the last 4 centuries, since the invention of the astronomical telescope. Currently, this activity index is available in two main forms: the International Sunspot Number initiated by R. Wolf in 1849 and the Group Number constructed more recently by Hoyt and Schatten (Sol. Phys. 179:189-219, 1998a, 181:491-512, 1998b). Unfortunately, those two series do not match by various aspects, inducing confusions and contradictions when used in crucial contemporary studies of the solar dynamo or of the solar forcing on the Earth climate. Recently, new efforts have been undertaken to diagnose and correct flaws and biases affecting both sunspot series, in the framework of a series of dedicated Sunspot Number Workshops. Here, we present a global overview of our current understanding of the sunspot number calibration. After retracing the construction of those two composite series, we present the new concepts and methods used to self-consistently re-calibrate the original sunspot series. While the early part of the sunspot record before 1800 is still characterized by large uncertainties due to poorly observed periods, the more recent sunspot numbers are mainly affected by three main inhomogeneities: in 1880-1915 for the Group Number and in 1947 and 1980-2014 for the Sunspot Number. After establishing those new corrections, we then consider the implications on our knowledge of solar activity over the last 400 years. The newly corrected series clearly indicates a progressive decline of solar activity before the onset of the Maunder Minimum, while the slowly rising trend of the activity after the Maunder Minimum is strongly reduced, suggesting that by the mid 18th century, solar activity had already returned to levels equivalent to those observed in recent solar cycles in the 20th century. We finally conclude with future prospects opened by this epochal revision of the Sunspot Number, the first one since Wolf himself, and its reconciliation with the Group Number, a long-awaited modernization that will feed solar cycle research into the 21st century.
引用
收藏
页码:35 / 103
页数:69
相关论文
共 157 条
[1]   For how long will the current grand maximum of solar activity persist? [J].
Abreu, J. A. ;
Beer, J. ;
Steinhilber, F. ;
Tobias, S. M. ;
Weiss, N. O. .
GEOPHYSICAL RESEARCH LETTERS, 2008, 35 (20)
[2]  
[Anonymous], 1937, HEVELIUS FLAMSTEED H
[3]  
[Anonymous], 2002, Journal of the American Association of Variable Star Observers
[4]  
[Anonymous], 1997, The Role of the Sun in Climate Change
[5]  
[Anonymous], 2014, SPACE SCI REV
[6]   Digitization of sunspot drawings by Staudacher in 1749-1796 [J].
Arlt, R. .
SOLAR PHYSICS, 2008, 247 (02) :399-410
[7]   Sunspot positions and sizes for 1825-1867 from the observations by Samuel Heinrich Schwabe [J].
Arlt, R. ;
Leussu, R. ;
Giese, N. ;
Mursula, K. ;
Usoskin, I. G. .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2013, 433 (04) :3165-3172
[8]   The sunspot observations by Samuel Heinrich Schwabe [J].
Arlt, R. .
ASTRONOMISCHE NACHRICHTEN, 2011, 332 (08) :805-814
[9]   The solar observations at Armagh Observatory in 1795-1797 [J].
Arlt, R. .
ASTRONOMISCHE NACHRICHTEN, 2009, 330 (04) :311-316
[10]   The Butterfly Diagram in the Eighteenth Century [J].
Arlt, R. .
SOLAR PHYSICS, 2009, 255 (01) :143-153