scholarly journals Sunspot number recalibration: The ~1840–1920 anomaly in the observer normalization factors of the group sunspot number

2017 ◽  
Vol 7 ◽  
pp. A12 ◽  
Author(s):  
Edward W. Cliver
Keyword(s):  
Sunspot Number ◽  
Group Sunspot ◽  
Group Sunspot Number ◽  
Normalization Factors

scholarly journals Reconstruction of solar irradiance using the Group sunspot number

2007 ◽  
Vol 40 (7) ◽  
pp. 986-989 ◽  
Author(s):  
L. Balmaceda ◽  
N.A. Krivova ◽  
S.K. Solanki
Keyword(s):  
Sunspot Number ◽  
Solar Irradiance ◽  
Group Sunspot ◽  
Group Sunspot Number

scholarly journals Long-term solar activity explored with wavelet methods

2006 ◽  
Vol 24 (2) ◽  
pp. 769-778 ◽  
Author(s):  
H. Lundstedt ◽  
L. Liszka ◽  
R. Lundin ◽  
R. Muscheler
Keyword(s):  
Solar Activity ◽  
Production Rate ◽  
Sunspot Number ◽  
Maunder Minimum ◽  
High Solar Activity ◽  
Solar Modulation ◽  
Group Sunspot ◽  
Group Sunspot Number ◽  
Wavelet Methods

Abstract. Long-term solar activity has been studied with a set of wavelet methods. The following indicators of long-term solar activity were used; the group sunspot number, the sunspot number, and the 14C production rate. Scalograms showed the very long-term scales of 2300 years (Hallstat cycle), 900-1000 years, 400-500 years, and 200 years (de Vries cycle). Scalograms of a newly-constructed 14C production rate showed interesting solar modulation during the Maunder minimum. Multi-Resolution Analysis (MRA) revealed the modulation in detail, as well as peaks of solar activity not seen in the sunspot number. In both the group sunspot number scalogram and the 14C production rate scalogram, a process appeared, starting or ending in late 1700. This process has not been discussed before. Its solar origin is unclear. The group sunspot number ampligram and the sunspot number ampligram showed the Maunder and the Dalton minima, and the period of high solar activity, which already started about 1900 and then decreased again after mid 1990. The decrease starts earlier for weaker components. Also, weak semiperiodic activity was found. Time Scale Spectra (TSS) showed both deterministic and stochastic processes behind the variability of the long-term solar activity. TSS of the 14C production rate, group sunspot number and Mt. Wilson sunspot index and plage index were compared in an attempt to interpret the features and processes behind the long-term variability.

The Discontinuity Circa 1885 in the Group Sunspot Number

Solar Physics ◽  
2016 ◽  
Vol 291 (9-10) ◽  
pp. 2763-2784 ◽  
Author(s):  
E. W. Cliver ◽  
A. G. Ling
Keyword(s):  
Sunspot Number ◽  
Group Sunspot ◽  
Group Sunspot Number

scholarly journals Revised Group Sunspot Number Values for 1640, 1652, and 1741

Solar Physics ◽  
2013 ◽  
Vol 289 (3) ◽  
pp. 803-808 ◽  
Author(s):  
J. M. Vaquero ◽  
R. M. Trigo
Keyword(s):  
Sunspot Number ◽  
Group Sunspot ◽  
Group Sunspot Number

scholarly journals How well do we know the sunspot number?

2011 ◽  
Vol 7 (S286) ◽  
pp. 27-33 ◽  
Author(s):  
Leif Svalgaard
Keyword(s):  
Sunspot Number ◽  
Number Series ◽  
Group Sunspot ◽  
Group Sunspot Number ◽  
Grand Maximum

AbstractWe show that only two adjustments are necessary to harmonize the Group Sunspot Number with the Zürich Sunspot Number. The latter has been increased from the 1940s on to the present by 20% due to weighting of sunspot counts according to size of the spots and can be corrected by increasing the earlier values as well. The Group Sunspot Number before ~1885 is too low by ~50%. With these adjustments a single sunspot number series results. Of note is that there is no longer a distinct Modern Grand Maximum.

A comparison of the spectral characteristics of the Wolf Sunspot Number (R Z) and Group Sunspot Number (R G)

Solar Physics ◽  
2004 ◽  
Vol 223 (1-2) ◽  
pp. 305-318 ◽  
Author(s):  
H. H. Faria ◽  
E. Echer ◽  
N. R. Rigozo ◽  
L. E. A. Vieira ◽  
D. J. R. Nordemann ◽  
...  
Keyword(s):  
Sunspot Number ◽  
Spectral Characteristics ◽  
Group Sunspot ◽  
Group Sunspot Number

scholarly journals Historical sunspot records

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Rainer Arlt ◽  
José M. Vaquero
Keyword(s):  
Time Series ◽  
19Th Century ◽  
Sunspot Number ◽  
Final Part ◽  
Group Sunspot ◽  
Naked Eye ◽  
Sunspot Numbers ◽  
The 19Th Century ◽  
Physical Quantities

AbstractSunspot observations are available in fairly good numbers since 1610, after the invention of the telescope. This review is concerned with those sunspot observations of which longer records and drawings in particular are available. Those records bear information beyond the classical sunspot numbers or group sunspot numbers. We begin with a brief summary on naked-eye sunspot observations, in particular those with drawings. They are followed by the records of drawings from 1610 to about 1900. The review is not a compilation of all known historical sunspot information. Some records contributing substantially to the sunspot number time series may therefore be absent. We also glance at the evolution of the understanding of what sunspots actually are, from 1610 to the 19th century. The final part of the review illuminates the physical quantities that can be derived from historical drawings.

scholarly journals Several Populations of Sunspot Group Numbers – Resolving a Conundrum

2021 ◽  
Author(s):  
Leif Svalgaard
Keyword(s):  
Solar Activity ◽  
Sunspot Number ◽  
Degrees Of Freedom ◽  
18Th Century ◽  
Number Series ◽  
Solar Observations ◽  
Group Sunspot Number ◽  
Group Number ◽  
Working Groups

<p>The long-standing disparity between the sunspot number record and the Hoyt and Schatten (1998, H&S) Group Sunspot Number series was initially resolved by the Clette et al. (2014) revision of the sunspot number and the group number series. The revisions resulted in a flurry of dissenting group number series while the revised sunspot number series was generally accepted. Thus, the disparity persisted and confusion reigned, with the choice of solar activity dataset continuing to be a free parameter. A number of workshops and follow-up collaborative efforts by the community have not yet brought clarity. We review here several lines of evidence that validate the original revisions put forward by Clette et al. (2014) and suggest that the perceived conundrum no longer need to delay acceptance and general use of the revised series. We argue that the solar observations constitute several distinct populations with different properties which explain the various discontinuities in the series. This is supported by several proxies: diurnal variation of the geomagnetic field, geomagnetic signature of the strength of the heliomagnetic field, and variation of radionuclides. The Waldmeier effect shows that the sunspot number scale has not changed over the last 270 years and a mistaken scale factor between observers Wolf and Wolfer explains the disparity beginning in 1882 between the sunspot number and the H&S reconstruction of the group number. Observations with replica of 18th century telescopes (with similar optical flaws) validate the early sunspot number scale; while a reconstruction of the group number with monthly resolution (with many more degrees of freedom) validate the size of Solar Cycle 11 given by the revised series that the dissenting series fail to meet. Based on the evidence at hand, we urge the working groups tasked with producing community-vetted and agreed upon solar activity series to complete their work expeditiously.</p>

scholarly journals Sunspot observations by Hisako Koyama: 1945–1996

2019 ◽  
Vol 492 (3) ◽  
pp. 4513-4527 ◽  
Author(s):  
Hisashi Hayakawa ◽  
Frédéric Clette ◽  
Toshihiro Horaguchi ◽  
Tomoya Iju ◽  
Delores J Knipp ◽  
...  
Keyword(s):  
Sunspot Number ◽  
Digital Data ◽  
Future Research ◽  
Number Series ◽  
Long Duration ◽  
Baseline Shift ◽  
Group Sunspot Number ◽  
Primary Reference ◽  
Comprehensive Recovery

ABSTRACT Sunspot records are the only observational tracer of solar activity that provides a fundamental, multicentury reference. Its homogeneity has been largely maintained with a succession of long-duration visual observers. In this article, we examine observations of one of the primary reference sunspot observers, Hisako Koyama. By consulting original archives of the National Museum of Nature and Science of Japan (hereafter, NMNS), we retrace the main steps of her solar-observing career, from 1945 to 1996. We also present the reconstruction of a full digital data base of her sunspot observations at the NMNS, with her original drawings and logbooks. Here, we extend the availability of her observational data from 1947–1984 to 1945–1996. Comparisons with the international sunspot number (Version 2) and with the group sunspot number series show a good global stability of Koyama's observations, with only temporary fluctuations over the main interval 1947–1982. Identifying drawings made by alternate observers throughout the series, we find that a single downward baseline shift in the record coincides with the partial contribution of replacement observers mostly after 1983. We determine the correction factor to bring the second part (1983–1996) to the same scale with Koyama's main interval (1947–1982). We find a downward jump by 9 per cent after 1983, which then remains stable until 1995. Overall, the high quality of Koyama's observations with her life-long dedication leaves a lasting legacy of this exceptional personal achievement. With this comprehensive recovery, we now make the totality of this legacy directly accessible and exploitable for future research.

Sign in / Sign up

Export Citation Format

Share Document