Full-disc Ca ii K observations—A window to past solar magnetism

Chatzistergos, Theodosios; Krivova, Natalie; Ermolli, I.

doi:10.3389/fspas.2022.1038949

Cited by 17 publications

(24 citation statements)

References 219 publications

(278 reference statements)

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“…We also notice considerable disagreement between the various series after 1970, even though all series show a decreasing trend over that period. The plage area series covers a shorter period (since 1892 Chatzistergos, 2017;Chatzistergos et al 2019aChatzistergos et al , 2022b than the sunspot data, but the derived cycle length record follows the one from sunspot data quite well. This is unsurprising, considering the relationship between sunspot and plage areas (e.g.…”

Section: Solar Cycle Length Seriesmentioning

confidence: 81%

Is there a link between the length of the solar cycle and Earth’s temperature?

Chatzistergos

2022

Rend. Fis. Acc. Lincei

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The Sun provides most of external energy to Earth’s system and thus has the potential of influencing it. Various studies reported a correlation between the solar cycle length and the northern hemisphere temperatures on Earth. Here, we reassess the cycle length record by incorporating the newly revised and updated sunspot number series as well as plage area composite, before comparing it to Earth temperature records. We find that cycle length series constructed from sunspot and plage data exhibit the same behaviour, both showing a downward trend after 1940. Our results suggest that the agreement between solar cycle lengths and temperatures found earlier is an artefact of (1) some arbitrary choices made by those studies when constructing the cycle length series as well as (2) a rather short time interval, to which the analyses were restricted. When considering the entire period of reliable sunspot and temperature data, these records diverge before about 1870 and after 1960. We also find a poor agreement between Earth temperatures and cycle length when using plage areas instead of sunspot data to derive cycle lengths. Our result of the divergence between cycle length series and Earth’s temperature after 1960 implies that the cycle length cannot be used to support a solar origin for the warming on Earth over the last 5 decades.

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Section: Solar Cycle Length Seriesmentioning

confidence: 81%

Is there a link between the length of the solar cycle and Earth’s temperature?

Chatzistergos

2022

Rend. Fis. Acc. Lincei

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“…To this aim, we have processed the complete series of Rome/PSPT observations with the methods by Chatzistergos et al (2018, which resulted to be more precise than other methods in the literature (see, e.g. Chatzistergos et al, 2022). We then segmented the obtained contrast images by assuming seven classes of solar features.…”

Section: Resultsmentioning

confidence: 99%

“…Finally, Rome/PSPT observations have also helped with the analysis of TSI and SSI measurements (e.g., Harder et al, 2019Harder et al, , 2022, and of the impact of solar spectral irradiance variability on Earth's atmosphere (e.g., Merkel et al, 2011;Ermolli et al, 2013). In addition, Rome/PSPT observations have been used as contextual data in the analysis of the small-scale processes revealed by high-resolution observations of the solar atmosphere (e.g., Ermolli et al, 2022).…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, an accurate identification and characterization of the various structures seen above the solar disk is an important step towards a better understanding of the solar irradiance changes. To this aim, we have processed the complete series of Rome/PSPT observations with the methods by Chatzistergos et al (2018, Chatzistergos et al, 2020a, which resulted to be more precise than other methods in the literature (see, e.g., Chatzistergos et al, 2022). We then segmented the obtained contrast images by assuming seven classes of solar features.…”

Section: Resultsmentioning

confidence: 99%

“…The observations recorded over the 27-year long period of regular Rome/PSPT operations have created a significant data archive consisting of more than 30,000 images of the full-disk photosphere and chromosphere and 1,5 Tb of data, 50% of which consisting of calibration series. Moreover, the Rome/PSPT is one of the few solar full-disk facilities currently operated, and which have made daily observations overlapping the historical time-series of data obtained with spectroheliographs at e.g., the Meudon, Coimbra, Kislovodsk, and Kharkiv observatories (e.g., Chatzistergos et al, 2022).…”

Section: Data Archivementioning

confidence: 99%

See 2 more Smart Citations

Rome Precision Solar Photometric Telescope: precision solar full-disk photometry during solar cycles 23–25

Ermolli

Giorgi

Chatzistergos

2022

Front. Astron. Space Sci.

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The Rome Precision Solar Photometric Telescope (Rome/PSPT) is a ground-based telescope engaged in precision solar photometry. It has a 27-year database of full-disk images of the photosphere and chromosphere beginning in 1996 and continuing to 2022. The solar images have been obtained daily, weather permitting, with approximately 2 arcsec/pixel scale in Ca II K line at 393.3 nm, G-band at 430.6 nm, and continuum in the blue and red parts of the spectrum at 409.4 nm and 607.2 nm, respectively. Regular observations were also performed at the green continuum at 535.7 nm for a period of about 18 months. Since the first-light, Rome/PSPT operations have been directed at understanding the source of short-and long-term solar irradiance changes, spanning from 1 min to several months, and from 1 year to a few solar cycles, respectively. However, Rome/PSPT data have also served to study a variety of other topics, including the photometric properties of solar disk features and of the supergranulation manifested by the chromospheric network. Moreover, they have been unique in allowing to connect series of historical and modern full-disk solar observations, especially the Ca II K line data. Here, we provide an overview of the Rome/PSPT telescope and of the solar monitoring carried out with it from its first light to the present, across solar cycles 23–25. We also briefly describe the main results achieved with Rome/PSPT data, and give an overview of new results being derived with the whole time series of observations covering the period 1996–2022.

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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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Full-disc Ca ii K observations—A window to past solar magnetism

Cited by 17 publications

References 219 publications

Is there a link between the length of the solar cycle and Earth’s temperature?

Is there a link between the length of the solar cycle and Earth’s temperature?

Rome Precision Solar Photometric Telescope: precision solar full-disk photometry during solar cycles 23–25

Recalibration of the Sunspot-Number: Status Report

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