Sunspot positions and sizes for 1825–1867 from the observations by Samuel Heinrich Schwabe

Arlt, R.; Leussu, Raisa; Giese, N.; Мурсула, К.; Usoskin, Ilya

doi:10.1093/mnras/stt961

Cited by 103 publications

(126 citation statements)

References 6 publications

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“…The dataset of sunspot group positions and sizes consists of three subsets: the revised version 1.3 of Schwabe data (Arlt 2011;Arlt et al 2013) for the period 1826-1867, the newly digitized Spörer data (Diercke et al 2015) for 1868-1874 (although these data are available from 1861-1894, we use them here only to fill the gap between Schwabe and RGO data), and the RGO/USAF/NOAA/SOON compilation 1 referred to collectively as the RGO data since 1875.…”

Section: Datamentioning

confidence: 99%

“…Accordingly, we did not apply any correction to this possible minor inconsistency. We only consider the high-quality Schwabe data with the quality tag 1, which means the highest possible accuracy for sunspot positions within the data (Arlt et al 2013). However, in some cases, particularly those related to the high-latitude spots, the accuracy of latitude determination may not be very high for Schwabe data, even for the best values were obtained from data with the formal quality tag.…”

Section: Datamentioning

confidence: 99%

“…Recently, the butterfly diagram has been studied for earlier times using digitized sunspot drawings of Staudacher (Arlt 2009), Schwabe (Arlt et al 2013), and Spörer (Diercke et al 2015). The latter two datasets now enable us to compose a continuous butterfly diagram since 1826, extending the RGO-based diagram by almost 50 years.…”

Section: Introductionmentioning

confidence: 99%

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Wings of the butterfly: Sunspot groups for 1826–2015

Leussu

Usoskin

Pavai

et al. 2017

A&A

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The spatio-temporal evolution of sunspot activity, the so-called Maunder butterfly diagram, has been continously available since 1874 using data from the Royal Greenwich Observatory, extended by SOON network data after 1976. Here we present a new extended butterfly diagram of sunspot group occurrence since 1826, using the recently digitized data from Schwabe (1826Schwabe ( -1867 and Spörer (1866Spörer ( -1880. The wings of the diagram are separated using a recently developed method based on an analysis of long gaps in sunspot group occurrence in different latitude bands. We define characteristic latitudes, corresponding to the start, end, and the largest extent of the wings (the F, L, and H latitudes). The H latitudes (30 • -45 • ) are highly significantly correlated with the strength of the wings (quantified by the total sum of the monthly numbers of sunspot groups). The F latitudes (20 • -30 • ) depict a weak tendency, especially in the southern hemisphere, to follow the wing strength. The L latitudes (2 • -10 • ) show no clear relation to the wing strength. Overall, stronger cycle wings tend to start at higher latitudes and have a greater wing extent. A strong (5-6)-cycle periodic oscillation is found in the start and end times of the wings and in the overlap and gaps between successive wings of one hemisphere. While the average wing overlap is zero in the southern hemisphere, it is two to three months in the north. A marginally significant oscillation of about ten solar cycles is found in the asymmetry of the L latitudes. The new long database of butterfly wings provides new observational constraints to solar dynamo models that discuss the spatio-temporal distribution of sunspot occurrence over the solar cycle and longer.

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Section: Datamentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

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Wings of the butterfly: Sunspot groups for 1826–2015

Leussu

Usoskin

Pavai

et al. 2017

A&A

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“…The 11-year Schwabe activity cycle corresponds to distributions of sunspots that are approximately symmetrical about the solar equator (e.g. Arlt et al 2013). Strict symmetry is violated owing both to the quasi-random emergence of sunspots and to the chaotic behaviour of the overall cycle.…”

Section: Introductionmentioning

confidence: 99%

Supermodulation of the Sun's magnetic activity: the effects of symmetry changes

Weiss¹,

Tobias²

2015

Mon. Not. R. Astron. Soc.

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In this paper we argue that the solar activity record, as revealed by telescopic observations and proxy data from the abundances of cosmogenic isotopes, is consistent with the action of a deterministic nonlinear chaotic dynamo. In particular we claim that the long timescale 'super-modulation' apparent in the isotopic record can be ascribed to switching of the dynamo between two different modulational patterns. The first (which is currently in operation) involves deep grand minima and occasional changes in symmetry triggered by these minima. The second, which exhibits only weak modulation and no grand minima, arises as a consequence of symmetry breaking. These processes are demonstrated for highly idealized simple models of the nonlinear dynamo equations.

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“…All of the sunspot areas in the group are individually calculated and their sum will give the total area of the sunspot group [8], [9]. The area of the sunspot group A M , on the solar disk is calculated by…”

Section: Introductionmentioning

confidence: 99%

A digital method to calculate the true areas of sunspot groups

Çakmak

2014

Exp Astron

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The areas of sunspots are the most prominent feature of the development of sunspot groups. Since the size of sunspot areas depend on the strength of the magnetic field, accurate measurements of these areas are important. In this study, a method which allows to measure true areas of the sunspots is introduced. A Stonyhurst disk is created by using a computer program and is coincided with solar images. By doing this, an accurate heliographic coordinate system is formed. Then, the true area of the whole sunspot group is calculated in square degrees with the aid of the heliographic coordinates of each picture element forming the image of the sunspot group. This technique's use is not limited with sunspot areas only. The areas of the flare and filaments observed on the chromospheric disk can also be calculated with the same method. In addition to this, it is possible to calculate the area of any occurrence on the solar disk, whether it is related to an activity or not.

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Sunspot positions and sizes for 1825–1867 from the observations by Samuel Heinrich Schwabe

Cited by 103 publications

References 6 publications

Wings of the butterfly: Sunspot groups for 1826–2015

Wings of the butterfly: Sunspot groups for 1826–2015

Supermodulation of the Sun's magnetic activity: the effects of symmetry changes

A digital method to calculate the true areas of sunspot groups

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