An Overview of Sunspot Observations in 1727–1748

Hayakawa, Hisashi; Hattori, Kentaro; Sôma, Mitsuru; Iju, Tomoya; Besser, Bruno P.; Kosaka, Shunsuke

doi:10.3847/1538-4357/ac6671

Cited by 12 publications

(7 citation statements)

References 52 publications

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“…Many of the data sets that have been recently uncovered and analyzed (e.g., Carrasco et al (2018b; for Hallaschka), for Wargentin), Nogales et al (2020; for Oriani), Hayakawa et al (2021e; for Johann Christoph Müller)) provide information (counts and/or drawings) for both S and G and thus can be applied to revisions of S N as well as to G N . As a manifestation of the increasing focus on recovery and archival of sunspot drawings, several recent works have constructed butterfly diagrams for historical observers (e.g., Leussu et al, 2017;Neuhäuser, Arlt, and Richter, 2018;Hayakawa, Besser, and Iju, 2020;Hayakawa et al, 2022a;Vokhmyanin, Arlt, and Zolotova, 2021; see Figure 9 below).…”

Section: Data Recovery and Revisionmentioning

confidence: 99%

“…Figure 8 shows that the 1730s and 1740s are the weakest link in the sunspot-number time series. Substantial attention has been focused on this data-poor interval (Section 2.2.1(c)) by Hayakawa et al (2022a) which is critical to connect Staudacher to the Maunder Minimum (Section 2.2.1(b); the low end of the lever arm for TSI reconstruction and climate-change studies; Solanki et al, 2013) and all preceding years, including those for which the sunspot record must be inferred from cosmogenic radionuclides.…”

Section: Galileo To Staudacher: Encompassing the Maunder Minimummentioning

confidence: 99%

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Recalibration of the Sunspot-Number: Status Report

et al. 2023

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We report progress on the ongoing recalibration of the Wolf sunspot number ($S_{\mathrm{N}}$ S N ) and group-sunspot number ($G_{\mathrm{N}}$ G N ) following the release of version 2.0 of $S_{\mathrm{N}}$ S N in 2015. This report constitutes both an update of the efforts reported in the 2016 Topical Issue of Solar Physics and a summary of work by the International Space Science Institute (ISSI) International Team formed in 2017 to develop optimal $S_{\mathrm{N}}$ S N and $G_{\mathrm{N}}$ G N reconstruction methods while continuing to expand the historical sunspot-number database. Significant progress has been made on the database side while more work is needed to bring the various proposed $S_{\mathrm{N}}$ S N and (primarily) $G_{\mathrm{N}}$ G N reconstruction methods closer to maturity, after which the new reconstructions (or combinations thereof) can be compared with (a) “benchmark” expectations for any normalization scheme (e.g., a general increase in observer normalization factors going back in time), and (b) independent proxy data series such as F10.7 and the daily range of variations of Earth’s undisturbed magnetic field. New versions of the underlying databases for $S_{\mathrm{N}}$ S N and $G_{\mathrm{N}}$ G N will shortly become available for years through 2022 and we anticipate the release of the next versions of these two time series in 2024.

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Section: Data Recovery and Revisionmentioning

confidence: 99%

Section: Galileo To Staudacher: Encompassing the Maunder Minimummentioning

confidence: 99%

Recalibration of the Sunspot-Number: Status Report

et al. 2023

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“…The last decade was marked by a rekindled interest in and extensive study of sunspot data, leading to a recovery of many new data, as well as corrections of existing records (e.g. Arlt et al 2013Arlt et al , 2016Vaquero et al 2016;Carrasco et al 2018Carrasco et al , 2019Carrasco et al , 2021aHayakawa et al 2020Hayakawa et al , 2021aHayakawa et al , 2022Vokhmyanin et al 2020;Bhattacharya et al 2021). Furthermore, various issues with the cross-calibration and compilation approaches of records of individual observers have been realised (Clette & Lefèvre 2016Lockwood et al 2016;Usoskin et al 2016b), leading to new techniques and several alternative GSN series (Usoskin et al 2016c(Usoskin et al , 2021aWillamo et al 2017;Chatzistergos et al 2017;Svalgaard & Schatten 2016;Cliver & Ling 2016) as well as version 2 of ISN (ISNv2 Clette & Lefèvre 2016).…”

Section: Sunspot Recordsmentioning

confidence: 99%

Long-term changes in solar activity and irradiance

Chatzistergos¹,

Krivova²,

Yeo³

2023

Preprint

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The Sun is the main energy source to Earth, and understanding its variability is of direct relevance to climate studies. Measurements of total solar irradiance (TSI) exist since 1978, but this is too short compared to climate-relevant time scales. Coming from a number of different instruments, these measurements require a cross-calibration, which is not straightforward, and thus several composite records have been created. All of them suggest a marginally decreasing trend since 1996. Most composites also feature a weak decrease over the entire period of observations, which is also seen in observations of the solar surface magnetic field and is further supported by Ca ii K data. Some inconsistencies, however, remain and overall the magnitude and even the presence of the long-term trend remain uncertain. Different models have been developed, which are used to understand the irradiance variability over the satellite period and to extend the records of solar irradiance back in time. Differing in their methodologies, all models require proxies of solar magnetic activity as input. The most widely used proxies are sunspot records and cosmogenic isotope data on centennial and millennial time scale, respectively. None of this, however, offers a sufficiently good, independent description of the long-term evolution of faculae and network responsible for solar brightening. This leads to significant uncertainties in the amplitude of the long-term changes in solar irradiance. Here we review recent efforts to improve irradiance reconstructions on time scales longer than the solar cycle and to reduce the existing uncertainty in the magnitude of the long-term variability. In particular, we highlight the potential of using 3D magnetohydrodynamical simulations of the solar atmosphere as input to more physical irradiance models and of historical full-disc Ca ii K observations encrypting direct facular information back to 1892.

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“…We have identified 547 days of sunspot observations that were included in his summary manuscript (MS Akc.1985/15) and his correspondence with Bode, apart from his close-up sketches for specific sunspot groups. Using the Waldmeier classification (see Kiepenheuer, 1953), we counted the sunspot groups in his records (Hayakawa et al, 2023) and compared them with the V16 database (Fig. 2) and contemporary longterm observers (Fig.…”

Section: Karl Von Lindener and His Observationsmentioning

confidence: 99%

Karl von Lindener’s sunspot observations during 1800–1827: Another long-term dataset for the Dalton Minimum

Hayakawa,

Arlt,

Iju

et al. 2023

J. Space Weather Space Clim.

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On a centennial timescale, solar activity oscillates quasi-periodically and also tends to get into a low-activity period. The Dalton Minimum (c.a. 1790s–1820s) was one of such low-activity periods that had been captured in telescopic sunspot observations. However, it has been challenging to analyse the Dalton Minimum, as contemporary source records remained mostly unpublished and almost inaccessible for the scientific community. Recent studies have established reliable datasets for sunspot group number, sunspot number, and sunspot positions. This study further analyzes independent Silesian sunspot observations from 1800 to 1827 archived in a manuscript the Library WrocławUniversity (Ms AKC.1985/15), complements it with the metadata for the observer Karl Christian Reinhold von Lindener. We identified 547 days of sunspot observations in these records and derived the sunspot group number, individual sunspot number, and sunspot positions between 1800 and 1827. The results of this study have significantly revised the von Lindener’s sunspot group number, which was only known for 517 days in scientific databases, and remove contamination from general descriptions. Using our results, we extend investigations into individual sunspots and derived their positions. In our analysis, we locate von Lindener’s sunspot positions in both solar hemispheres and contrast the Dalton Minimum with the Maunder Minimum, adding further independent credits to the previous results for Derfflinger and Prantner’s datasets. Sunspot positions are also slightly biased towards the northern solar hemisphere in early Solar Cycle 6 (1812 – 1813). The high-latitude sunspot positions indicate the onset of Solar Cycle 7 as early as June 1822.

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An Overview of Sunspot Observations in 1727–1748

Cited by 12 publications

References 52 publications

Recalibration of the Sunspot-Number: Status Report

Recalibration of the Sunspot-Number: Status Report

Long-term changes in solar activity and irradiance

Karl von Lindener’s sunspot observations during 1800–1827: Another long-term dataset for the Dalton Minimum

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