Understanding the secular variability of solar irradiance: the potential of Ca II K observations | Journal of Space Weather and Space Climate

Topical Issue - Space Climate: Long-term effects of solar variability on the Earth’s environment

Open Access

Review

Issue		J. Space Weather Space Clim. Volume 14, 2024 Topical Issue - Space Climate: Long-term effects of solar variability on the Earth’s environment


Article Number		9
Number of page(s)		24
DOI		https://doi.org/10.1051/swsc/2024006
Published online		12 April 2024

Ambelu T, Falayi EO, Elemo EO, Oladosu O. 2011. Estimation of total solar irradiance from sunspot number. Latin-American J Phys Educ 5(4): 741–745. [Google Scholar]
Amdur T, Huybers P. 2023. A bayesian model for inferring total solar irradiance from proxies and direct observations: application to the ACRIM gap. J Geophys Res 128(15): e2023JD038941. https://doi.org/10.1029/2023JD038941. [CrossRef] [Google Scholar]
Arlt R, Vaquero JM. 2020. Historical sunspot records. Living Rev Sol Phys 17: 1. https://doi.org/10.1007/s41116-020-0023-y. [CrossRef] [Google Scholar]
Arvesen JC, Griffin RN Jr, Pearson BD Jr. 1969. Determination of extraterrestrial solar spectral irradiance from a research aircraft. Appl Opt 8(11): 2215–2232. https://doi.org/10.1364/AO.8.002215. [CrossRef] [Google Scholar]
Babcock HW, Babcock HD. 1955. The Sun’s magnetic field, 1952–1954. Astrophys J 121: 349–366. https://doi.org/10.1086/145994. [CrossRef] [Google Scholar]
Ball WT, Unruh YC, Krivova NA, Solanki S, Wenzler T, Mortlock DJ, Jaffe AH. 2012. Reconstruction of total solar irradiance 1974–2009. A&A 541: A27. https://doi.org/10.1051/0004-6361/201118702. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Barata T, Carvalho S, Dorotovič I, Pinheiro FJG, Garcia A, Fernandes J, Lourenço AM. 2018. Software tool for automatic detection of solar plages in the Coimbra Observatory spectroheliograms. Astron Comput 24: 70–83. https://doi.org/10.1016/j.ascom.2018.06.003. [CrossRef] [Google Scholar]
Beer J, McCracken K, von Steiger R. 2012. Cosmogenic radionuclides – theory and applications in the terrestrial and space environments. Physics of earth and space environments, 1st edn. Springer, Berlin, Heidelberg. [Google Scholar]
Berrilli F, Criscuoli S, Penza V, Lovric M. 2020. Long-term (1749–2015) variations of solar UV spectral indices. Sol Phys 295: 3. https://doi.org/10.1007/s11207-020-01603-5. [CrossRef] [Google Scholar]
Bertello L, Pevtsov A, Tlatov A, Singh J. 2016. Correlation between sunspot number and Ca II K emission index. Sol Phy 291: 2967–2979. https://doi.org/10.1007/s11207-016-0927-9. [CrossRef] [Google Scholar]
Bertello L, Pevtsov AA, Ulrich RK. 2020. 70 years of chromospheric solar activity and dynamics. Astrophys J 897: 181. https://doi.org/10.3847/1538-4357/ab9746. [CrossRef] [Google Scholar]
Bertello L, Ulrich RK, Boyden JE. 2010. The Mount Wilson Ca II K plage index time series. Sol Phys 264: 31–44. https://doi.org/10.1007/s11207-010-9570-z. [CrossRef] [Google Scholar]
Bhattacharya S, Lefèvre L, Hayakawa H, Jansen M, Clette F. 2023. Scale transfer in 1849: Heinrich Schwabe to Rudolf Wolf. Sol Phys 298(1): 12. https://doi.org/10.1007/s11207-022-02103-4. [CrossRef] [Google Scholar]
Brehm N, Bayliss A, Christl M, Synal H-A, Adolphi F, et al. 2021. Eleven-year solar cycles over the last millennium revealed by radiocarbon in tree rings. Nat Geosci 14: 10–15. https://doi.org/10.1038/s41561-020-00674-0. [CrossRef] [Google Scholar]
Brueckner GE, Bartoe J-DF. 1983. Observations of high-energy jets in the corona above the quiet sun, the heating of the corona, and the acceleration of the solar wind. Astrophys J 272: 329–348. https://doi.org/10.1086/161297. [CrossRef] [Google Scholar]
Bühler D, Lagg A, Solanki SK. 2013. Quiet Sun magnetic fields observed by Hinode: support for a local dynamo. A&A 555: A33. https://doi.org/10.1051/0004-6361/201321152. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Carrasco VMS, Nogales JM, Vaquero JM, Chatzistergos T, Ermolli I. 2021. A note on the sunspot and prominence records made by Angelo Secchi during the period 1871–1875. J Space Weather Space Clim 11: 51. https://doi.org/10.1051/swsc/2021033. [CrossRef] [EDP Sciences] [Google Scholar]
Chapman GA, Boyden JE. 1986. Solar irradiance variations derived from magnetograms. Astrophys J 302: L71. https://doi.org/10.1086/184640. [CrossRef] [Google Scholar]
Chapman GA, Cookson AM, Dobias JJ. 1996. Variations in total solar irradiance during solar cycle 22. J Geophys Res 101(A6): 13541–13548. https://doi.org/10.1029/96JA00683. [CrossRef] [Google Scholar]
Chapman GA, Cookson AM, Preminger DG. 2012. Comparison of TSI from SORCE TIM with SFO ground-based photometry. Sol Phys 276: 34–41. https://doi.org/10.1007/s11207-011-9867-6. [Google Scholar]
Chapman GA, Cookson AM, Preminger DG. 2013. Modeling total solar irradiance with san fernando observatory ground-based photometry: comparison with ACRIM, PMOD, and RMIB composites. Sol Phys 283: 295–305. https://doi.org/10.1007/s11207-013-0233-8. [CrossRef] [Google Scholar]
Chapman GA, Herzog AD, Laico DE, Lawrence JK, Templer MS. 1989. Photometric measurements of solar irradiance variations due to sunspots. Astrophys J 343: 547. https://doi.org/10.1086/167728. [CrossRef] [Google Scholar]
Chapman GA, Herzog AD, Lawrence JK, Walton SR, Hudson HS, Fisher BM. 1992. Precise ground-based solar photometry and variations of total irradiance. J Geophys Res 97(A6): 8211–8219. https://doi.org/10.1029/91JA03018. [CrossRef] [Google Scholar]
Chatterjee S, Banerjee D, Ravindra B. 2016. A butterfly diagram and carrington maps for century-long Ca II K spectroheliograms from the Kodaikanal observatory. Astrophys J 827(1): 87. https://doi.org/10.3847/0004-637X/827/1/87. [CrossRef] [Google Scholar]
Chatzistergos T. 2017. Analysis of historical solar observations and long-term changes in solar irradiance. PhD Thesis, Uni-edition, Georg-August Universität, Göttingen, Germany. https://doi.org/10.53846/goediss-6507. [Google Scholar]
Chatzistergos T. 2023. Is there a link between the length of the solar cycle and Earth’s temperature? Rend Lincei Sci Fis Nat 34: 11–21. https://doi.org/10.1007/s12210-022-01127-z. [CrossRef] [Google Scholar]
Chatzistergos T. 2024. A discussion of implausible total solar-irradiance variations since 1700. Sol Phys 299: 21. https://doi.org/10.1007/s11207-024-02262-6. [CrossRef] [Google Scholar]
Chatzistergos T, Ermolli I, Banerjee D, Barata T, Chouinavas I, et al. 2023a. Analysis of full-disc H alpha observations: Carrington maps and filament properties in 1909–2022. A&A 680: A15. https://doi.org/10.1051/0004-6361/202347536. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Ermolli I, Falco M, Giorgi F, Guglielmino SL, Krivova NA, Romano P, Solanki SK. 2019a. Historical solar Ca II K observations at the Rome and Catania observatories. Il Nuovo Cimento 42C: 5. https://doi.org/10.1393/ncc/i2019-19005-2. [Google Scholar]
Chatzistergos T, Ermolli I, Giorgi F, Krivova NA, Puiu CC. 2020a. Modelling solar irradiance from ground-based photometric observations. J Space Weather Space Clim 10: 45. https://doi.org/10.1051/swsc/2020047. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Ermolli I, Krivova NA, Barata T, Carvalho S, Malherbe J-M. 2022a. Scrutinising the relationship between plage areas and sunspot areas and numbers. A&A 667: A167. https://doi.org/10.1051/0004-6361/202244913. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Ermolli I, Krivova NA, Solanki SK. 2018a. Ca II K spectroheliograms for studies of long-term changes in solar irradiance. In: Long-term datasets for the understanding of solar and stellar magnetic cycles, vol. 340 of IAU Symposium, Banerjee D, Jiang J, Kusano K, Solanki S (Eds.) Cambridge University Press, Cambridge, UK. pp. 125–128. https://doi.org/10.1017/S1743921318001825. [Google Scholar]
Chatzistergos T, Ermolli I, Krivova NA, Solanki SK. 2019b. Analysis of full disc Ca II K spectroheliograms – II. Towards an accurate assessment of long-term variations in plage areas. A&A 625: A69. https://doi.org/10.1051/0004-6361/201834402. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Ermolli I, Krivova NA, Solanki SK. 2020. b. Historical solar Ca II K observations at the Kyoto and Sacramento Peak observatories. J Phys Conf Ser 1548: 012007. https://doi.org/10.1088/1742-6596/1548/1/012007. [CrossRef] [Google Scholar]
Chatzistergos T, Ermolli I, Krivova NA, Solanki SK, Banerjee D, et al. 2020c. Analysis of full-disc Ca II K spectroheliograms – III. Plage area composite series covering 1892–2019. A&A 639: A88. https://doi.org/10.1051/0004-6361/202037746. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Ermolli I, Solanki SK, Krivova NA. 2016. Exploiting four historical Ca II K spectroheliogram archives. In: Coimbra solar physics meeting: ground-based solar observations in the space instrumentation era. Astronomical Society of the Pacific Conference, vol. 504 of Astronomical Society of the Pacific Conference Series. Dorotovic I, Fischer CE, Temmer M (Eds.), San Francisco. pp. 227–231. [Google Scholar]
Chatzistergos T, Ermolli I, Solanki SK, Krivova NA. 2018b. Analysis of full disc Ca II K spectroheliograms – I. Photometric calibration and centre-to-limb variation compensation. A&A 609: A92. https://doi.org/10.1051/0004-6361/201731511. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Ermolli I, Solanki SK, Krivova NA, Banerjee D, Jha BK, Chatterjee S. 2019c. Delving into the historical Ca II K archive from the Kodaikanal Observatory: the potential of the most recent digitized series. Sol Phys 294: 145. https://doi.org/10.1007/s11207-019-1532-5. [CrossRef] [Google Scholar]
Chatzistergos T, Ermolli I, Solanki Sami K, Krivova Natalie A, Giorgi F, Yeo Kok L. 2019d. Recovering the unsigned photospheric magnetic field from Ca II K observations. A&A 626(1): A114. https://doi.org/10.1051/0004-6361/201935131. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Krivova NA, Ermolli I. 2022b. Full-disc Ca II K observations – a window to past solar magnetism. Front Astron Space Sci 9: 1038949. https://doi.org/10.3389/fspas.2022.1038949. [CrossRef] [Google Scholar]
Chatzistergos T, Krivova NA, Ermolli I, Yeo KL, Mandal S, Solanki SK, Kopp G, Malherbe J-M. 2021a. Reconstructing solar irradiance from historical Ca II K observations – I. Method and its validation. A&A 656: A104. https://doi.org/10.1051/0004-6361/202141516. [CrossRef] [EDP Sciences] [Google Scholar]
Chatzistergos T, Krivova NA, Ermolli I, Yeo KL, Solanki SK, Puiu CC, Giorgi F, Mandal S. 2021b. Reconstructing solar irradiance from Ca II K observations. Authorea. https://doi.org/10.1002/essoar.10505871.1. [Google Scholar]
Chatzistergos T, Krivova NA, Yeo KL. 2023b. Long-term changes in solar activity and irradiance. J Atmos Sol Terr Phys 252: 106150. https://org/10.1016/j.jastp.2023.106150. [CrossRef] [Google Scholar]
Chatzistergos T, Usoskin IG, Kovaltsov GA, Krivova NA, Solanki SK. 2017. New reconstruction of the sunspot group numbers since 1739 using direct calibration and “backbone” methods. A&A 602: A69. https://doi.org/10.1051/0004-6361/201630045. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Clette F, Lefèvre L, Bechet S, Ramelli R, Cagnotti M. 2021. Reconstruction of the sunspot number source database and the 1947 Zurich discontinuity. Sol Phys 296: 137. https://doi.org/10.1007/s11207-021-01882-6. [CrossRef] [Google Scholar]
Clette F, Lefèvre L, Chatzistergos T, Hayakawa H, Carrasco VMS, et al. 2023. Recalibration of the sunspot-number: status report. Sol Phys 298: 44. https://doi.org/10.1007/s11207-023-02136-3. [CrossRef] [Google Scholar]
Cook JW, Brueckner GE, Vanhoosier ME. 1980. Variability of the solar flux in the far ultraviolet 1175–2100 Å. J Geophys Res 85(A5): 2257–2268. https://doi.org/10.1029/JA085iA05p02257. [CrossRef] [Google Scholar]
Criscuoli S. 2016. Angular Dependence of the Facular-Sunspot Coverage Relation as Derived by MDI Magnetograms. Sol Phys 291: 1957–1975. https://doi.org/10.1007/s11207-016-0947-5. [CrossRef] [Google Scholar]
Criscuoli S. 2019. Effects of continuum fudging on non-LTE synthesis of stellar spectra. I. Effects on estimates of UV continua and solar spectral irradiance variability. Astrophys J 872: 1. https://doi.org/10.3847/1538-4357/aaf6b7. [Google Scholar]
Criscuoli S, Marchenko S, DeLand M, Choudhary D, Kopp G. 2023. Understanding Sun-as-a-star variability of solar balmer lines. Astrophys J 951: 151. https://doi.org/10.3847/1538-4357/acd17d. [CrossRef] [Google Scholar]
Criscuoli S, Penza V, Lovric M, Berrilli F. 2018. The correlation of synthetic UV color versus Mg ii index along the solar cycle. Astrophys J 865: 22. https://doi.org/10.3847/1538-4357/aad809. [CrossRef] [Google Scholar]
Dasi-Espuig M, Jiang J, Krivova NA, Solanki SK, Unruh YC, Yeo KL. 2016. Reconstruction of spectral solar irradiance since 1700 from simulated magnetograms. A&A 590: A63. https://doi.org/10.1051/0004-6361/201527993. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Dewitte S, Crommelynck D, Joukoff A. 2004. Total solar irradiance observations from DIARAD/VIRGO. J Geophys Res Space Phys 109: A02102. https://doi.org/10.1029/2002JA009694. [CrossRef] [Google Scholar]
Dewitte S, Nevens S. 2016. The total solar irradiance climate data record. Astrophys J 830: 25. https://doi.org/10.3847/0004-637X/830/1/25. [CrossRef] [Google Scholar]
Dineva E, Pearson J, Ilyin I, Verma M, Diercke A, Strassmeier KG, Denker C. 2022. Characterization of chromospheric activity based on Sun-as-a-star spectral and disk-resolved activity indices. Astron Nachr 343: e223996. https://doi.org/10.1002/asna.20223996. [CrossRef] [Google Scholar]
Doerr H-P, Vitas N, Fabbian D. 2016. How different are the Liège and Hamburg atlases of the solar spectrum? A&A 590: A118. https://doi.org/10.1051/0004-6361/201628570. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Domingo V, Ermolli I, Fox P, Fröhlich C, Haberreiter M, et al. 2009. Solar surface magnetism and irradiance on time scales from days to the 11-year cycle. Space Sci Rev 145: 337–380. https://doi.org/10.1007/s11214-009-9562-1. [CrossRef] [Google Scholar]
Dudok de Wit T, Kopp G, Fröhlich C, Schöll M. 2017. Methodology to create a new total solar irradiance record: Making a composite out of multiple data records. Geophys Res Lett 44(3): 196–1203. https://doi.org/10.1002/2016GL071866. [Google Scholar]
Egeland R, Soon W, Baliunas S, Hall JC, Pevtsov AA, Bertello L. 2017. The Mount Wilson observatory S-index of the Sun. Astrophys J 835: 25. https://doi.org/10.3847/1538-4357/835/1/25. [CrossRef] [Google Scholar]
Egorova T, Schmutz W, Rozanov E, Shapiro AI, Usoskin I, Beer J, Tagirov RV, Peter T. 2018. Revised historical solar irradiance forcing. A&A 615: A85. https://doi.org/10.1051/0004-6361/201731199. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Ermolli I, Caccin B, Centrone M, Penza V. 2003. Modeling solar irradiance variations through full-disk images and semi-empirical atmospheric models. Mem Soc Astron Ital 74: 603–606. [Google Scholar]
Ermolli I, Chatzistergos T. 2023. Reconstructing solar irradiance over the period 1996–2022. In: EGU23, the 25th EGU General Assembly, Vienna, Austria and Online, 23–28 April. Available at https://doi.org/10.5194/egusphere-egu23-16293. [Google Scholar]
Ermolli I, Chatzistergos T, Giorgi F, Carrasco VMS, Aparicio AJP, Chinnici I. 2023. Solar Observations by Angelo Secchi. I. Digitization of original documents and analysis of group numbers over the period of 1853–1878. Astrophys J Suppl Ser 269: 53. https://doi.org/10.3847/1538-4365/ad0886. [CrossRef] [Google Scholar]
Ermolli I, Chatzistergos T, Krivova NA, Solanki SK. 2018. The potential of Ca II K observations for solar activity and variability studies. In: Long-term datasets for the understanding of solar and stellar magnetic cycles, vol. 340 of IAU Symposium. Banerjee D, Jiang J, Kusano K, Solanki S (Eds.) Cambridge University Press, Cambridge. pp. 115–120. https://doi.org/10.1017/S1743921318001849. [Google Scholar]
Ermolli I, Criscuoli S, Giorgi F. 2011. Recent results from optical synoptic observations of the solar atmosphere with ground-based instruments. Contrib Astron Obs Skalnaté Pleso 41: 73–84. [Google Scholar]
Ermolli I, Criscuoli S, Uitenbroek H, Giorgi F, Rast MP, Solanki SK. 2010. Radiative emission of solar features in the Ca II K line: comparison of measurements and models. A&A 535: A55. https://doi.org/10.1051/0004-6361/201014762. [CrossRef] [EDP Sciences] [Google Scholar]
Ermolli I, Giorgi F, Chatzistergos T. 2022. Rome Precision Solar Photometric Telescope: precision solar full-disk photometry during solar cycles 23–25. Front Astron Space Sci 9: 1042740. https://doi.org/10.3389/fspas.2022.1042740. [CrossRef] [Google Scholar]
Ermolli I, Marchei E, Centrone M, Criscuoli S, Giorgi F, Perna C. 2009a. The digitized archive of the Arcetri spectroheliograms. Preliminary results from the analysis of Ca II K images. A&A 499: 627–632. https://doi.org/10.1051/0004-6361/200811406. [CrossRef] [EDP Sciences] [Google Scholar]
Ermolli I, Matthes K, Dudok de Wit T, Krivova NA, Tourpali K, et al. 2013. Recent variability of the solar spectral irradiance and its impact on climate modelling. Atmos Chem Phys 13: 3945–3977. https://doi.org/10.5194/acp-13-3945-2013. [CrossRef] [Google Scholar]
Ermolli I, Shibasaki K, Tlatov A, van Driel-Gesztelyi L. 2014. Solar cycle indices from the photosphere to the corona: measurements and underlying physics. Space Sci Rev 186: 105–135. https://doi.org/10.1007/s11214-014-0089-8. [CrossRef] [Google Scholar]
Ermolli I, Solanki SK, Tlatov AG, Krivova NA, Ulrich RK, Singh J. 2009b. Comparison among Ca II K spectroheliogram time series with an application to solar activity studies. Astrophys J 698: 1000. https://doi.org/10.1088/0004-637X/698/2/1000. [CrossRef] [Google Scholar]
Finsterle W, Montillet JP, Schmutz W, Šikonja R, Kolar L, Treven L. 2021. The total solar irradiance during the recent solar minimum period measured by SOHO/VIRGO. Sci Rep 11(1): 7835. https://doi.org/10.1038/s41598-021-87108-y. [CrossRef] [Google Scholar]
Fligge M, Solanki SK. 1998. Long-term behavior of emission from solar faculae: steps towards a robust index. A&A 332: 1082–1086. [Google Scholar]
Fligge M, Solanki SK, Unruh YC. 2000. Modelling short-term spectral irradiance variations. Space Sci Rev 94: 139–144. https://doi.org/10.1023/A:1026706920261. [CrossRef] [Google Scholar]
Fontenla J, White OR, Fox PA, Avrett EH, Kurucz RL. 1999. Calculation of solar irradiances. I. Synthesis of the solar spectrum. Astrophys J 518: 480–499. https://doi.org/10.1086/307258. [CrossRef] [Google Scholar]
Fontenla JM, Landi E. 2018. Bright network, UVA, and the physical modeling of solar spectral and total irradiance in recent solar cycles. Astrophys J 861: 120. https://doi.org/10.3847/1538-4357/aac388. [CrossRef] [Google Scholar]
Foukal P. 1993. The curious case of the greenwich faculae. Sol Phys 148: 219–232. https://doi.org/10.1007/BF00645087. [CrossRef] [Google Scholar]
Foukal P. 1996. The behavior of solar magnetic plages measured from Mt. Wilson observations between 1915–1984. Geophys Res Lett 23: 2169–2172. https://doi.org/10.1029/96GL01356. [CrossRef] [Google Scholar]
Foukal P. 1998. Extension of the F10.7 Index to 1905 using Mt. Wilson Ca K Spectroheliograms. Geophys Res Lett 25: 2909–2912. https://doi.org/10.1029/98GL02057. [CrossRef] [Google Scholar]
Foukal P. 2002. A comparison of variable solar total and ultraviolet irradiance outputs in the 20th century. Geophys Res Lett 29: 2089. https://doi.org/10.1029/2002GL015474. [CrossRef] [Google Scholar]
Foukal P. 2012. A new look at solar irradiance variation. Sol Phys 279: 365–381. https://doi.org/10.1007/s11207-012-0017-6. [CrossRef] [Google Scholar]
Foukal P, Lean J. 1986. The influence of faculae on total solar irradiance and luminosity. Astrophys J 302: 826–835. https://doi.org/10.1086/164043. [CrossRef] [Google Scholar]
Foukal P, Lean J. 1988. Magnetic modulation of solar luminosity by photospheric activity. Astrophys J 19: 924. https://doi.org/10.1086/166297. [Google Scholar]
Fröhlich C. 2000. Observations of irradiance variations. Space Sci Rev 94: 15–24. https://doi.org/10.1023/A:1026765712084. [CrossRef] [Google Scholar]
Fröhlich C. 2006. Solar irradiance variability since 1978. Revision of the PMOD Composite during Solar Cycle 21. Space Sci Rev 125: 53–65. https://doi.org/10.1007/s11214-006-9046-5. [Google Scholar]
Fröhlich C. 2012. Total solar irradiance observations. Surv Geophy 33: 453–473. https://doi.org/10.1007/s10712-011-9168-5. [CrossRef] [Google Scholar]
Fröhlich C, Crommelynck DA, Wehrli C, Anklin M, Dewitte S, Fichot A, Finsterle W, Jiménez A, Chevalier A, Roth H. 1997. In-flight performance of the virgo solar irradiance instruments on Soho. Sol Phys 175: 267–286. https://doi.org/10.1023/A:1004929108864. [CrossRef] [Google Scholar]
Fröhlich C, Lean J. 1997. Total solar irradiance variations: the construction of a composite and its comparison with models. In: Correlated Phenomena at the Sun, in the Heliosphere and in Geospace. 31st ESLAB Symposium, ESTEC, The Netherlands. European Space Agency, ESA SP-415, 22–25 September . Wilson A (Ed.) ESA Publications Division, Noordwijk. p. 227. [Google Scholar]
Fröhlich C, Romero J, Roth H, Wehrli C, Andersen BN, et al. 1995. VIRGO: experiment for helioseismology and solar irradiance monitoring. Sol Phys 162: 101–128. https://doi.org/10.1007/BF00733428. [CrossRef] [Google Scholar]
Gray LJ, Beer J, Geller M, Haigh JD, Lockwood M, et al. 2010. Solar influences on climate. Rev Geophys 48: RG4001. https://doi.org/10.1029/2009RG000282. [Google Scholar]
Haigh JD. 2007. The Sun and the Earth’s climate. Living Rev Sol Phys 4: 2. https://doi.org/10.12942/lrsp-2007-2. [CrossRef] [Google Scholar]
Hale GE. 1892. Photographs of solar phenomena obtained with the spectroheliograph of the Kenwood Astro-Physical Observatory. A&A (formerly The Sidereal Messenger) 11: 235. [Google Scholar]
Hanaoka Y. 2013. Long-term synoptic observations of the Sun at the National Astronomical Observatory of Japan. J Phys Conf Ser 440: 012041. https://doi.org/10.1088/1742-6596/440/1/012041. [CrossRef] [Google Scholar]
Harder J, Béland S, Penton SV, Richard E, Weatherhead E, Araujo-Pradere E. 2022. SORCE and TSIS-1 SIM comparison: absolute irradiance scale reconciliation. Earth Space Sci 9: e2021EA002122. https://doi.org/10.1029/2021EA002122. [CrossRef] [Google Scholar]
Harder JW, Béland S, Snow M. 2019. SORCE-based solar spectral irradiance (SSI) record for input into chemistry-climate studies. Earth Space Sci 6: 2487. https://doi.org/10.1029/2019EA000737. [CrossRef] [Google Scholar]
Hickey JR, Stowe LL, Jacobowitz H, Pellegrino P, Maschhoff RH, House F, Vonder Haar TH. 1980. Initial solar irradiance determinations from nimbus 7 cavity radiometer measurements. Science 208: 281–283. https://doi.org/10.1126/science.208.4441.281. [NASA ADS] [CrossRef] [Google Scholar]
Hoyt DV, Schatten KH. 1998. Group sunspot numbers: a new solar activity reconstruction. Sol Phys 179: 189–219. https://doi.org/10.1023/A:1005007527816. [CrossRef] [Google Scholar]
Illarionov E, Arlt R. 2022. Reconstruction of the solar activity from the catalogs of the Zurich Observatory. Sol Phys 297: 79. https://doi.org/10.1007/s11207-022-02015-3. [CrossRef] [Google Scholar]
IPCC. 2021. Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Masson-Delmotte V, Zhai P, Pirani A, Connors S, Péan C, Berger S, Caud N, Chen Y, Goldfarb L, Gomis M, Huang M, Leitzell K, Lonnoy E, Matthews J, Maycock T, Waterfield T, Yelekçi O, Yu R, Zhou B (Eds.) Cambridge University Press, Cambridge, UK and New York, NY, USA. https://doi.org/10.1017/9781009157896. [Google Scholar]
Jha BK, Hegde M, Priyadarshi A, Mandal S, Ravindra B, Banerjee D. 2022. Extending the sunspot area series from Kodaikanal Solar Observatory. Front Astron Space Sci 9: 1019751. https://doi.org/10.3389/fspas.2022.1019751. [CrossRef] [Google Scholar]
Johannesson A, Marquette W, Zirin H. 1995. Reproduction of the Lyman \alpha irradiance variability from analysis of full-disk images in the CaII K-line. Sol Phys 161: 201–204. https://doi.org/10.1007/BF00732094. [CrossRef] [Google Scholar]
Johannesson A, Marquette WH, Zirin H. 1998. A 10-year set of CA II K-line filtergrams. Sol Phys 177: 265–278. https://doi.org/10.1023/A:1004940227692. [CrossRef] [Google Scholar]
Kahil F, Riethmüller TL, Solanki SK. 2017. Brightness of solar magnetic elements as a function of magnetic flux at high spatial resolution. Astrophys J Suppl Ser 229: 12. https://doi.org/10.3847/1538-4365/229/1/12. [CrossRef] [Google Scholar]
Kaiser Kudsk SG, Knudsen MF, Karoff C, Baittinger C, Misios S, Olsen J. 2022. Solar variability between 650 CE and 1900 – Novel insights from a global compilation of new and existing high-resolution 14C records. Quat Sci Rev 292: 107617. https://doi.org/10.1016/j.quascirev.2022.107617. [CrossRef] [Google Scholar]
Kakuwa J, Ueno S. 2021. Investigation of the long-term variation of solar Ca II K intensity. I. Density-to-intensity calibration formula for historical photographic plates. Astrophys J Suppl Ser 254: 44. https://doi.org/10.3847/1538-4365/abfbe3. [CrossRef] [Google Scholar]
Kakuwa J, Ueno S. 2022. Investigation of the long-term variation of solar Ca II K intensity. II. Reconstruction of solar UV irradiance. Astrophys J 928: 97. https://doi.org/10.3847/1538-4357/ac5963. [CrossRef] [Google Scholar]
Keil SL, Worden SP. 1984. Variations in the solar calcium K line 1976–1982. Astrophys J 276: 766–781. https://doi.org/10.1086/161663. [CrossRef] [Google Scholar]
Keller CU, Harvey JW, Giampapa MS. 2003. SOLIS: an innovative suite of synoptic solar instruments. In: Innovative Telescopes and Instrumentation for Solar Astrophysics, vol. 4853. Keil SL, Avakian SV, Society of Photo-optical Instrumentation Engineers (Eds.) University of Michigan. pp. 194–204. https://doi.org/10.1117/12.460373. [CrossRef] [Google Scholar]
Kopp G. 2016. Magnitudes and timescales of total solar irradiance variability. J Space Weather Space Clim 6: A30. https://doi.org/10.1051/swsc/2016025. [CrossRef] [EDP Sciences] [Google Scholar]
Kopp G. 2021. Science highlights and final updates from 17 years of total solar irradiance measurements from the SOlar Radiation and Climate Experiment/Total Irradiance Monitor (SORCE/TIM). Sol Phys 296: 133. https://doi.org/10.1007/s11207-021-01853-x. [CrossRef] [Google Scholar]
Kopp G, Lawrence G. 2005. The total irradiance monitor (TIM): instrument design. Sol Phys 230: 91–109. https://doi.org/10.1007/s11207-005-7446-4. [CrossRef] [Google Scholar]
Kren AC, Pilewskie P, Coddington O. 2017. Where does Earth’s atmosphere get its energy? J Space Weather Space Clim 7: A10. https://doi.org/10.1051/swsc/2017007. [CrossRef] [EDP Sciences] [Google Scholar]
Krivova NA. 2018. Solar irradiance variability and Earth’s climate: impacts and human adaptation. In: Climate changes in the holocene. Chiotis E (Ed.) CRC Press, Boca Raton, FL. pp. 107–120. https://doi.org/10.1201/9781351260244-4. [Google Scholar]
Krivova NA, Solanki SK, Fligge M, Unruh YC. 2003. Reconstruction of solar irradiance variations in cycle 23: Is solar surface magnetism the cause? A&A 399: L1–L4. https://doi.org/10.1051/0004-6361:20030029. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Krivova NA, Solanki SK, Hofer B, Wu C-J, Usoskin IG, Cameron R. 2021. Modelling the evolution of the Sun’s open and total magnetic flux. A&A 650: A70. https://doi.org/10.1051/0004-6361/202140504. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Krivova NA, Solanki SK, Wenzler T. 2009. ACRIM-gap and total solar irradiance revisited: Is there a secular trend between 1986 and 1996? Geophys Res Lett 36: L20101. https://doi.org/10.1029/2009GL040707. [CrossRef] [Google Scholar]
Lean JL. 2000. Short term, direct indices of solar variability. Space Sci Rev 94: 39–51. https://doi.org/10.1023/A:1026726029831. [CrossRef] [Google Scholar]
Lean JL. 2018. Estimating solar irradiance since 850 CE. Earth Space Sci 5: 133–149. https://doi.org/10.1002/2017EA000357. [CrossRef] [Google Scholar]
Lean JL, Coddington O, Marchenko SV, Machol J, DeLand MT, Kopp G. 2020. Solar irradiance variability: modeling the measurements. Earth Space Sci 7: e2019EA000645. https://doi.org/10.1029/2019EA000645. [CrossRef] [Google Scholar]
Lean JL, Cook J, Marquette W, Johannesson A. 1998. Magnetic sources of the solar irradiance cycle. Astrophys J 492: 390. https://doi.org/10.1086/305015. [CrossRef] [Google Scholar]
Lean JL, Repoff TP. 1987. A statistical analysis of solar flux variations over time scales of solar rotation: 1978–1982. J Geophys Res Atmos 92: 5555–5563. https://doi.org/10.1029/JD092iD05p05555. [CrossRef] [Google Scholar]
Lean JL, Skumanich A. 1983. Variability of the Lyman alpha flux with solar activity. J Geophys Res 88: 5751–5759. https://doi.org/10.1029/JA088iA07p05751. [CrossRef] [Google Scholar]
Lean JL, White OR, Livingston WC, Picone JM. 2001. Variability of a composite chromospheric irradiance index during the 11-year activity cycle and over longer time periods. J Geophys Res Space Phys 106: 10645–10658. https://doi.org/10.1029/2000JA000340. [CrossRef] [Google Scholar]
Lee RB III, Gibson MA, Wilson RS, Thomas S. 1995. Long-term total solar irradiance variability during sunspot cycle 22. J Geophys Res Space Phys 100: 1667–1675. https://doi.org/10.1029/94JA02897. [CrossRef] [Google Scholar]
Lefèbvre S, Ulrich RK, Webster LS, Varadi F, Javaraiah J, Bertello L, Werden L, Boyden JE, Gilman P. 2005. The solar photograph archive of the Mount Wilson Observatory. A resource for a century of digital data. Mem Soc Astron Ital 76: 862–867. [Google Scholar]
Lites BW, Centeno R, McIntosh SW. 2014. The solar cycle dependence of the weak internetwork flux. Publ Astron Soc Japan 66(SP1): S4. https://doi.org/10.1093/pasj/psu082. [CrossRef] [Google Scholar]
Livingston W, Wallace L. 2003. The Sun’s immutable basal quiet atmosphere. Sol Phys 212: 227–237. https://doi.org/10.1023/A:1022994002653. [CrossRef] [Google Scholar]
Livingston W, Wallace L, White OR, Giampapa MS. 2007. Sun-as-a-star spectrum variations 1974–2006. Astrophys J 657: 1137. https://doi.org/10.1086/511127. [CrossRef] [Google Scholar]
Livingston WC, Harvey J, Pierce AK, Schrage D, Gillespie B, Simmons J, Slaughter C. 1976. Kitt Peak 60-cm vacuum telescope. Appl Opt 15: 33–39. https://doi.org/10.1364/AO.15.000033. [CrossRef] [Google Scholar]
Lockwood M, Ball WT. 2020. Placing limits on long-term variations in quiet-Sun irradiance and their contribution to total solar irradiance and solar radiative forcing of climate. Proc R Soc A: Math Phys Eng Sci 476: 20200077. https://doi.org/10.1098/rspa.2020.0077. [Google Scholar]
Lockwood M, Fröhlich C. 2008. Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature. II. Different reconstructions of the total solar irradiance variation and dependence on response time scale. Proc R Soc A: Math Phys Eng Sci 464: 1367–1385. https://doi.org/10.1098/rspa.2007.0347. [Google Scholar]
Loukitcheva M, Solanki SK, White SM. 2009. The relationship between chromospheric emissions and magnetic field strength. A&A 497: 273–285. https://doi.org/10.1051/0004-6361/200811133. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Lourenço A, Carvalho S, Barata T, Garcia A, Carrasco V, Peixinho N. 2019. Solar observations at the Coimbra Astronomical Observatory. Open Astron 28: 165–179. https://doi.org/10.1515/astro-2019-0015. [CrossRef] [Google Scholar]
Machol J, Snow M, Woodraska D, Woods T, Viereck R, Coddington O. 2019. An improved lyman-alpha composite. Earth Space Sci 6: 2263–2272. https://doi.org/10.1029/2019EA000648. [CrossRef] [Google Scholar]
Malherbe J-M. 2023. 130 years of spectroheliograms at Paris-Meudon observatories (1893–2023). J Hist Astron 54: 274–315. https://doi.org/10.1177/00218286231184193. [CrossRef] [Google Scholar]
Mandal S, Krivova NA, Solanki SK, Sinha N, Banerjee D. 2020. Sunspot area catalog revisited: daily cross-calibrated areas since 1874. A&A 640: A78. https://doi.org/10.1051/0004-6361/202037547. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Marchenko SV, Lean JL, DeLand MT. 2022. Relationship between total solar irradiance and magnetic flux during solar minima. Astrophys J 936: 158. https://doi.org/10.3847/1538-4357/ac8a98. [CrossRef] [Google Scholar]
Matthes K, Funke B, Andersson ME, Barnard L, Beer J, et al. 2017. Solar forcing for CMIP6 (v3.2). Geosci Model Dev 10: 2247–2302. https://doi.org/10.5194/gmd-10-2247-2017. [CrossRef] [Google Scholar]
Mauceri S, Coddington O, Lyles D, Pilewskie P. 2019. Neural network for solar irradiance modeling (NN-SIM). Sol Phys 294: 160. https://doi.org/10.1007/s11207-019-1555-y. [CrossRef] [Google Scholar]
Meftah M, Hauchecorne A, Irbah A, Cessateur G, Bekki S, Damé L, Bolsée D, Pereira N. 2016. Solar spectral irradiance at 782 nm as measured by the SES sensor onboard picard. Sol Phys 291(4): 1043–1057. https://doi.org/10.1007/s11207-016-0885-2. [CrossRef] [Google Scholar]
Mironova IA, Aplin KL, Arnold F, Bazilevskaya GA, Harrison RG, Krivolutsky AA, Nicoll KA, Rozanov EV, Turunen E, Usoskin IG. 2015. Energetic particle influence on the Earth’s atmosphere. Space Sci Rev 194: 1–96. https://doi.org/10.1007/s11214-015-0185-4. [CrossRef] [Google Scholar]
Mishra DK, Routh S, Jha BK, Chatzistergos T, Basu J, Chatterjee S, Banerjee D, Ermolli I. 2024. Differential rotation of the solar chromosphere: a century-long perspective from Kodaikanal Solar Observatory Ca II K data. Astrophys J 961: 40. https://doi.org/10.3847/1538-4357/ad1188. [CrossRef] [Google Scholar]
Montillet J-P, Finsterle W, Kermarrec G, Sikonja R, Haberreiter M, Schmutz W, Dudok de Wit T. 2022. Data fusion of total solar irradiance composite time series using 41 years of satellite measurements. J Geophys Res Atmos 127: e2021JD036146. https://doi.org/10.1029/2021JD036146. [CrossRef] [Google Scholar]
Mordvinov AV, Karak BB, Banerjee D, Chatterjee S, Golubeva EM, Khlystova AI. 2020. Long-term evolution of the Sun’s magnetic field during cycles 15–19 based on their proxies from Kodaikanal Solar Observatory. Astrophys J 902: L15. https://doi.org/10.3847/2041-8213/abba80. [CrossRef] [Google Scholar]
Morrill J. 2005. Calculating solar UV spectral irradiance using observed spectral radiance and full disk Ca II K images. Mem Soc Astron Ital 76: 850–855. [Google Scholar]
Morrill JS, Floyd L, McMullin D. 2011a. The solar ultraviolet spectrum estimated using the Mg II index and Ca II K disk activity. Sol Phys 296: 253–267. https://doi.org/10.1007/s11207-011-9708-7. [CrossRef] [Google Scholar]
Morrill JS, Floyd L, Ulrich R, Weaver S, McMullin D. 2011b. Estimating the Mg ii index from 1961 through 1981 using Ca II K images from the Mt Wilson Observatory. Sol Phys 270: 109–124. https://doi.org/10.1007/s11207-011-9724-7. [CrossRef] [Google Scholar]
Murabito M, Ermolli I, Chatzistergos T, Jafarzadeh S, Giorgi F, Voort LRVD. 2023. Investigating the effect of solar ambient and data characteristics on Ca II K observations and line profile measurements. Astrophys J 947: 18. https://doi.org/10.3847/1538-4357/acc529. [CrossRef] [Google Scholar]
Muscheler R, Adolphi F, Herbst K, Nilsson A. 2016. The revised sunspot record in comparison to cosmogenic radionuclide-based solar activity reconstructions. Sol Phys 291: 3025–3043. https://doi.org/10.1007/s11207-016-0969-z. [Google Scholar]
Muscheler R, Joos F, Beer J, Müller SA, Vonmoos M, Snowball I. 2007. Solar activity during the last 1000 yr inferred from radionuclide records. Quat Sci Rev 26: 82–97. https://doi.org/10.1016/j.quascirev.2006.07.012. [Google Scholar]
Neckel H. 1999. Spectral atlas of solar absolute disk-averaged and disk-center intensity from 3290 to 12510 Å (Brault and Neckel, 1987) now available from Hamburg observatory FTP site. Sol Phys 184: 421. https://doi.org/10.1023/A:1017165208013. [CrossRef] [Google Scholar]
Nèmec N-E, Shapiro AI, Işık E, Sowmya K, Solanki SK, Krivova NA, Cameron RH, Gizon L. 2022. Faculae cancel out on the surfaces of active suns. Astrophys J Lett 934: L23. https://doi.org/10.3847/2041-8213/ac8155. [CrossRef] [Google Scholar]
Oranje BJ. 1982. A selective solar irradiance spectrometer. A&A 109: 32–36. [Google Scholar]
Oranje BJ. 1983. The Ca II K emission from the sun as a star. I – Observational parameters. A&A 122: 88–94. [Google Scholar]
Oster L, Schatten KH, Sofia S. 1982. Solar irradiance variations due to active regions. Astrophys J 256: 768–779. https://doi.org/10.1086/159949. [CrossRef] [Google Scholar]
Owens MJ, Forsyth RJ. 2013. The heliospheric magnetic field. Living Rev Sol Phys 10: 5. https://doi.org/10.12942/lrsp-2013-5. [CrossRef] [Google Scholar]
Pal PS, Verma M, Rendtel J, Manrique SJG, Enke H, Denker C. 2020. Solar observatory Einstein Tower: data release of the digitized solar full-disk photographic plate archive. Astron Nachr 341: 1–13. https://doi.org/10.1002/asna.202013791. [CrossRef] [Google Scholar]
Pap JM, Marquette WH, Donnelly RF. 1991. Modelling solar irradiances using ground-based measurements. Adv Space Res 11: 271–274. https://doi.org/10.1016/0273-1177(91)90391-V. [CrossRef] [Google Scholar]
Penza V, Berrilli F, Bertello L, Cantoresi M, Criscuoli S. 2021. Prediction of sunspot and plage coverage for solar cycle 25. Astrophys J Lett 922: L12. https://doi.org/10.3847/2041-8213/ac3663. [CrossRef] [Google Scholar]
Penza V, Berrilli F, Bertello L, Cantoresi M, Criscuoli S, Giobbi P. 2022. Total solar irradiance during the last five centuries. Astrophys J 937: 84. https://doi.org/10.3847/1538-4357/ac8a4b. [CrossRef] [Google Scholar]
Penza V, Caccin B, Ermolli I, Centrone M, Gomez MT. 2003. Modeling solar irradiance variations through PSPT images and semiempirical models. In: Solar variability as an input to the Earth’s environment. International Solar Cycle Studies (ISCS) Symposium, 23–28 June 2003, Tatranská Lomnica, Slovak Republic. ESA SP-535. Wilson A (Ed.) ESA Publications Division, Noordwijk. pp. 299–302. [Google Scholar]
Pesnell WD, Thompson BJ, Chamberlin PC. 2012. The solar dynamics observatory (SDO). Sol Phys 275: 3–15. https://doi.org/10.1007/s11207-011-9841-3. [Google Scholar]
Pilewskie P, Kopp G, Richard E, Coddington O, Sparn T, Woods T. 2018. TSIS-1 and continuity of the total and spectral solar irradiance climate data record. In: Vol. 20 of Proceedings from the 20th EGU General Assembly, Vienna, Austria, 4–13 April. [Google Scholar]
Preminger DG, Walton SR, Chapman GA. 2002. Photometric quantities for solar irradiance modeling. J Geophys Res Space Phys 107: 1354. https://doi.org/10.1029/2001JA009169. [CrossRef] [Google Scholar]
Puiu CC. 2019. Modeling solar irradiance variations on timescales from day to solar cycle with ground-based observations. Master’s thesis. University of Rome, Sapienza. [Google Scholar]
Rottman GJ, Barth CA, Thomas RJ, Mount GH, Lawrence GM, Rusch DW, Sanders RW, Thomas GE, London J. 1982. Solar spectral irradiance, 120 to 190 nm, October 13, 1981–January 3, 1982. Geophys Res Lett 9: 587–590. https://doi.org/10.1029/GL009i005p00587. [CrossRef] [Google Scholar]
Rozanov E, Calisto M, Egorova T, Peter T, Schmutz W. 2012. Influence of the precipitating energetic particles on atmospheric chemistry and climate. Surv Geophy 33: 483–501. https://doi.org/10.1007/s10712-012-9192-0. [CrossRef] [Google Scholar]
Rozanov E, Callis L, Schlesinger M, Yang F, Andronova N, Zubov V. 2005. Atmospheric response to NO_y source due to energetic electron precipitation. Geophys Res Lett 32: L14811. https://doi.org/10.1029/2005GL023041. [CrossRef] [Google Scholar]
Samain D, Simon PC. 1976. Solar flux determination in the spectral range 150–210 nm. Sol Phys 49: 33–41. https://doi.org/10.1007/BF00221483. [CrossRef] [Google Scholar]
Scafetta N. 2023. Empirical assessment of the role of the Sun in climate change using balanced multi-proxy solar records. Geosci Front 14: 101650. https://doi.org/10.1016/j.gsf.2023.101650. [CrossRef] [Google Scholar]
Schatten KH, Miller N, Sofia S, Endal AS, Chapman G. 1985. The importance of improved facular observations in understanding solar constant variations. Astrophys J 294: 689–696. https://doi.org/10.1086/163339. [CrossRef] [Google Scholar]
Scherrer PH, Schou J, Bush RI, Kosovichev AG, Bogart RS, et al. 2012. The helioseismic and magnetic imager (HMI) investigation for the solar dynamics observatory (SDO). Sol Phys 275: 207–227. https://doi.org/10.1007/s11207-011-9834-2. [CrossRef] [Google Scholar]
Schmutz WK. 2021. Changes in the total solar irradiance and climatic effects. J Space Weather Space Clim 11: 40. https://doi.org/10.1051/swsc/2021016. [CrossRef] [EDP Sciences] [Google Scholar]
Schou J, Scherrer PH, Bush RI, Wachter R, Couvidat S, et al. 2012. Design and ground calibration of the helioseismic and magnetic imager (HMI) instrument on the solar dynamics observatory (SDO). Sol Phys 275: 229–259. https://doi.org/10.1007/s11207-011-9842-2. [CrossRef] [Google Scholar]
Schrijver CJ, Harvey KL. 1989. The distribution of solar magnetic fluxes and the nonlinearity of stellar flux-flux relations. Astrophys J 130: 481–488. https://doi.org/10.1086/167721. [CrossRef] [Google Scholar]
Shapiro AI, Schmutz W, Rozanov E, Schoell M, Haberreiter M, Shapiro AV, Nyeki S. 2011. A new approach to the long-term reconstruction of the solar irradiance leads to large historical solar forcing. A&A 529: A69. https://doi.org/10.1051/0004-6361/201016173. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Shapiro AI, Solanki SK, Krivova NA, Cameron RH, Yeo KL, Schmutz WK. 2017. The nature of solar brightness variations. Nat Astron 1: 612–616. https://doi.org/10.1038/s41550-017-0217-y. [CrossRef] [Google Scholar]
Shapiro AI, Solanki SK, Krivova NA, Schmutz WK, Ball WT, Knaack R, Rozanov EV, Unruh YC. 2014. Variability of Sun-like stars: reproducing observed photometric trends. A&A 569: A38. https://doi.org/10.1051/0004-6361/201323086. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Sindhuja G, Singh J. 2015. Temporal variation of Ca II K Line profile of the sun during the solar cycle 22 and 23. J Astrophys Astron 36: 81–101. https://doi.org/10.1007/s12036-015-9330-4. [CrossRef] [Google Scholar]
Sinnhuber M, Funke B. 2020. Energetic electron precipitation into the atmosphere. In: The dynamic loss of Earth’s radiation belts. Jaynes AN, Usanova ME (Eds.) Elsevier. pp. 279–321. [CrossRef] [Google Scholar]
Sinnhuber M, Nieder H, Wieters N. 2012. Energetic particle precipitation and the chemistry of the mesosphere/lower thermosphere. Surv Geophy 33: 1281–1334. https://doi.org/10.1007/s10712-012-9201-3. [CrossRef] [Google Scholar]
Skumanich A, Smythe C, Frazier EN. 1975. On the statistical description of inhomogeneities in the quiet solar atmosphere. I – Linear regression analysis and absolute calibration of multichannel observations of the Ca/+/ emission network. Astrophys J 200: 747–764. https://doi.org/10.1086/153846. [CrossRef] [Google Scholar]
Snow M, McClintock WE, Woods TN, Elliott JP. 2022. SOLar-stellar irradiance comparison experiment II (SOLSTICE II): End-of-mission validation of the SOLSTICE Technique. Sol Phys 297: 55. https://doi.org/10.1007/s11207-022-01984-9. [CrossRef] [Google Scholar]
Sofia S, Oster L, Schatten K. 1982. Solar irradiance modulation by active regions during 1980. Sol Phys 80: 87–98. https://doi.org/10.1007/BF00153425. [CrossRef] [Google Scholar]
Solanki SK. 2003. Sunspots: an overview. Astron Astrophys Rev 11: 153–286. https://doi.org/10.1007/s00159-003-0018-4. [CrossRef] [Google Scholar]
Solanki SK, Fligge M. 1998. Solar irradiance since 1874 revisited. Geophys Res Lett 25: 341–344. https://doi.org/10.1029/98GL50038. [CrossRef] [Google Scholar]
Solanki SK, Inhester B, Schüssler M. 2006. The solar magnetic field. Rep Prog Phys 69: 563–568. https://doi.org/10.1088/0034-4885/69/3/R02. [CrossRef] [Google Scholar]
Solanki SK, Krivova NA, Haigh JD. 2013. Solar irradiance variability and climate. Ann Rev Astron Astrophys 51: 311–351. https://doi.org/10.1146/annurev-astro-082812-141007. [CrossRef] [Google Scholar]
Solanki SK, Unruh YC. 2013. Solar irradiance variability. Astron Nachr 334: 145–150. https://doi.org/10.1002/asna.201211752. [CrossRef] [Google Scholar]
Sowmya K, Shapiro AI, Witzke V, Nèmec N-E, Chatzistergos T, Yeo KL, Krivova NA, Solanki SK. 2021. Modeling stellar Ca II H and K emission variations. I. Effect of inclination on the S-index. Astrophys J 914: 21. https://doi.org/10.3847/1538-4357/abf247. [CrossRef] [Google Scholar]
Steinegger M, Brandt PN, Haupt HF. 1996. Sunspot irradiance deficit, facular excess, and the energy balance of solar active regions. A&A 310: 635–645. [Google Scholar]
Steinhilber F, Abreu JA, Beer J, Brunner I, Christl M, et al. 2012. 9,400 years of cosmic radiation and solar activity from ice cores and tree rings. Proc Nat Acad Sci 109: 5967–5971. https://doi.org/10.1073/pnas.1118965109. [CrossRef] [Google Scholar]
Svalgaard L, Schatten KH. 2016. Reconstruction of the sunspot group number: the backbone method. Sol Phys 291: 2653–2684. https://doi.org/10.1007/s11207-015-0815-8. [CrossRef] [Google Scholar]
Tlatov AG, Pevtsov AA, Singh J. 2009. A new method of calibration of photographic plates from three historic data sets. Sol Phys 255: 239–251. https://doi.org/10.1007/s11207-009-9326-9. [CrossRef] [Google Scholar]
Usoskin IG, Kovaltsov GA, Lockwood M, Mursula K, Owens M, Solanki SK. 2016a. A new calibrated sunspot group series since 1749: statistics of active day fractions. Sol Phys 291: 2685–2708. https://doi.org/10.1007/s11207-015-0838-1. [CrossRef] [Google Scholar]
Usoskin IG, Gallet Y, Lopes F, Kovaltsov GA, Hulot G. 2016b. Solar activity during the Holocene: the Hallstatt cycle and its consequence for grand minima and maxima. A&A 585: A150. https://doi.org/10.1051/0004-6361/201527295. [CrossRef] [EDP Sciences] [Google Scholar]
Vaquero JM, Svalgaard L, Carrasco VMS, Clette F, Lefèvre L, Gallego MC, Arlt R, Aparicio AJP, Richard J-G, Howe R. 2016. A revised collection of sunspot group numbers. Sol Phys 291: 3061. https://doi.org/10.1007/s11207-016-0982-2. [CrossRef] [Google Scholar]
Vaquero JM, Vázquez M. 2009. The sun recorded through history: scientific data extracted from historical documents, vol. 361 of Astrophysics and Space Science Library. Springer New York, New York, NY. [Google Scholar]
Vieira LEA, Solanki SK. 2010. Evolution of the solar magnetic flux on time scales of years to millenia. A&A 509: A100. https://doi.org/10.1051/0004-6361/200913276. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Vieira LEA, Solanki SK, Krivova NA, Usoskin I. 2011. Evolution of the solar irradiance during the Holocene. A&A 531: A6. https://doi.org/10.1051/0004-6361/201015843. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Vogler FL, Brandt PN, Otruba W, Hanslmeier A. 2005. Solar irradiance variations modelled from Ca II K excess and magnetic field. Hvar Observatory Bulletin 29: 79–88. [Google Scholar]
Walton SR, Preminger DG, Chapman GA. 2003. A statistical analysis of the characteristics of sunspots and faculae. Sol Phys 213: 301–317. https://doi.org/10.1023/A:1023986901169. [CrossRef] [Google Scholar]
Wang YM, Lean JL. 2021. A new reconstruction of the sun’s magnetic field and total irradiance since 1700. Astrophys J 920: 100. https://doi.org/10.3847/1538-4357/ac1740. [CrossRef] [Google Scholar]
Warren HP, Mariska JT, Lean J, Marquette W, Johannesson A. 1996. Modeling solar extreme ultraviolet irradiance variability using emission measure distributions. Geophys Res Lett 23: 2207–2210. https://doi.org/10.1029/96GL01481. [CrossRef] [Google Scholar]
Wenzler T, Solanki SK, Krivova NA. 2009. Reconstructed and measured total solar irradiance: Is there a secular trend between 1978 and 2003? Geophys Res Lett 36: L11102. https://doi.org/10.1029/2009GL037519. [CrossRef] [Google Scholar]
White OR, Livingston W. 1978. Solar luminosity variation. II – Behavior of calcium H and K at solar minimum and the onset of cycle 21. Astrophys J 226: 679–686. https://doi.org/10.1086/156650. [CrossRef] [Google Scholar]
White OR, Livingston WC. 1981. Solar luminosity variation. III – Calcium K variation from solar minimum to maximum in cycle 21. Astrophys J 249: 798–816. https://doi.org/10.1086/159338. [CrossRef] [Google Scholar]
Willis DM, Wild MN, Appleby GM, Macdonald LT. 2016. The Greenwich photo-heliographic results (1874–1885): observing telescopes, photographic processes, and solar images. Sol Phys 291: 2553–2586. https://doi.org/10.1007/s11207-016-0894-1. [CrossRef] [Google Scholar]
Willson RC. 1997. Total solar irradiance trend during solar cycles 21 and 22. Science 26: 1963–1965. https://doi.org/10.1126/science.277.5334.1963. [CrossRef] [Google Scholar]
Willson RC, Gulkis S, Janssen M, Hudson HS, Chapman GA. 1981. Observations of solar irradiance variability. Science 211: 700–702. https://doi.org/10.1126/science.211.4483.700. [CrossRef] [Google Scholar]
Willson RC, Hudson HS. 1988. Solar luminosity variations in solar cycle 21. Nature 332: 810–812. https://doi.org/10.1038/332810a0. [NASA ADS] [CrossRef] [Google Scholar]
Willson RC, Mordvinov AV. 2003. Composite total solar irradiance time series show a secular 0.04%/decade trend. In: AGU Fall Meeting Abstracts. [Google Scholar]
Woods TN, Harder JW, Kopp G, Snow M. 2022. Solar-cycle variability results from the solar radiation and climate experiment (SORCE) mission. Sol Phys 297: 43. https://doi.org/10.1007/s11207-022-01980-z. [CrossRef] [Google Scholar]
Woods TN, Rottman GJ, Ucker GJ. 1993. Solar-Stellar irradiance comparison experiment 1. II – instrument calibrations. J Geophys Res 98: 10679–10694. https://doi.org/10.1029/93JD00463. [CrossRef] [Google Scholar]
Worden JR, Woods TN, Bowman KW. 2001. Far-ultraviolet intensities and center-to-limb variations of active regions and quiet sun using UARS SOLSTICE irradiance measurements and ground-based spectroheliograms. Astrophys J 560: 1020. https://doi.org/10.1086/323058. [CrossRef] [Google Scholar]
Wu C-J, Krivova NA, Solanki SK, Usoskin IG. 2018a. Solar total and spectral irradiance reconstruction over the last 9000 years. A&A 620: A120. https://doi.org/10.1051/0004-6361/201832956. [CrossRef] [EDP Sciences] [Google Scholar]
Wu CJ, Usoskin IG, Krivova N, Kovaltsov GA, Baroni M, Bard E, Solanki SK. 2018b. Solar activity over nine millennia: a consistent multi-proxy reconstruction. A&A 615: A93. https://doi.org/10.1051/0004-6361/201731892. [CrossRef] [EDP Sciences] [Google Scholar]
Xu H, Lei B, Li Z. 2021. A reconstruction of total solar irradiance based on wavelet analysis. Earth Space Sci 8: e2021EA001819. https://doi.org/10.1029/2021EA001819. [CrossRef] [Google Scholar]
Yeo KL, Ball WT, Krivova NA, Solanki SK, Unruh YC, Morrill J. 2015a. UV solar irradiance in observations and the NRLSSI and SATIRE-S models. J Geophys Res Space Phys 120: 6055–6070. https://doi.org/10.1002/2015JA021277. [CrossRef] [Google Scholar]
Yeo KL, Krivova NA, Solanki SK. 2015b. Solar cycle variation in solar irradiance. In: The solar activity cycle. Space Sciences Series of ISSI, vol. 53, Balogh A, Hudson H, Petrovay K, von Steiger R (Eds.), Springer, New York, NY. pp. 137–167. https://doi.org/10.1007/978-1-4939-2584-1_5 [Google Scholar]
Yeo KL, Krivova NA, Solanki SK. 2017a. EMPIRE: A robust empirical reconstruction of solar irradiance variability. J Geophys Res Space Phys 122: 3888–3914. https://doi.org/10.1002/2016JA023733. [CrossRef] [Google Scholar]
Yeo KL, Krivova NA, Solanki SK, Glassmeier KH. 2014. Reconstruction of total and spectral solar irradiance from 1974 to 2013 based on KPVT, SoHO/MDI, and SDO/HMI observations. A&A 570: A85. https://doi.org/10.1051/0004-6361/201423628. [NASA ADS] [CrossRef] [EDP Sciences] [Google Scholar]
Yeo KL, Solanki SK, Krivova NA. 2020a. How faculae and network relate to sunspots, and the implications for solar and stellar brightness variations. A&A 639: A139. https://doi.org/10.1051/0004-6361/202037739. [CrossRef] [EDP Sciences] [Google Scholar]
Yeo KL, Solanki SK, Krivova NA, Rempel M, Anusha LS, Shapiro AI, Tagirov RV, Witzke V. 2020b. The dimmest state of the Sun. Geophys Res Lett 47: e2020GL090243. https://doi.org/10.1029/2020GL090243. [CrossRef] [Google Scholar]
Yeo KL, Solanki SK, Norris CM, Beeck B, Unruh YC, Krivova NA. 2017b. Solar irradiance variability is caused by the magnetic activity on the solar surface. Phys Rev Lett 119: 091102. https://doi.org/10.1103/PhysRevLett.119.091102. [CrossRef] [Google Scholar]

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.